cssi/SciSciGPT-SciSciNet huggingface dataset:
Polyhedral Clinching Auctions and the AdWords Polytope

A central issue in applying auction theory in practice is the problem of dealing with budget-constrained agents. A desirable goal in practice is to design incentive compatible, individually rational, and Pareto optimal auctions while respecting the budget constraints. Achieving this goal is particularly challenging in the presence of nontrivial combinatorial constraints over the set of feasible allocations.Toward this goal and motivated by AdWords auctions, we present an auction for polymatroidal environments satisfying these properties. Our auction employs a novel clinching technique with a clean geometric description and only needs an oracle access to the submodular function defining the polymatroid. As a result, this auction not only simplifies and generalizes all previous results, it applies to several new applications including AdWords Auctions, bandwidth markets, and video on demand. In particular, our characterization of the AdWords auction as polymatroidal constraints might be of independent interest. This allows us to design the first mechanism for Ad Auctions taking into account simultaneously budgets, multiple keywords and multiple slots.We show that it is impossible to extend this result to generic polyhedral constraints. This also implies an impossibility result for multiunit auctions with decreasing marginal utilities in the presence of budget constraints.
London: A Multi-Century Struggle for Sustainable Development in an Urban Environment

In this paper I sketch key episodes in the two thousand year history of interactions between society and environment that have shaped the City of London and its hinterlands. My purpose in writing it has been to provide an empirical puzzle for use in teaching and theorizing about the long term coevolution of social-environmental systems and the potential role of policy interventions in guiding that coevolution toward sustainability. I undertook it because while a lively body of theory has begun to emerge seeking to explain such coevolution, rich descriptive characterizations of how specific social-environmental systems have in fact changed over the long time periods (multi-decade to multi-century) relevant to sustainable development remain relatively rare. One result is that the field of sustainability science lacks a sufficient number of the rich empirical puzzles that any field of science needs to challenge its theorizing, modeling and predictions. This paper reflects the beginning of an effort to provide one such characterization on a topic central to sustainability: the long term development of cities and their hinterlands.
Sufficiency, separability and temporal probabilistic models

Suppose we are given the conditional probability of one variable given some other variables. Normally the full joint distribution over the conditioning variables is required to determine the probability of the conditioned variable. Under what circumstances are the marginal distributions over the conditioning variables sufficient to determine the probability of the conditioned variable? Sufficiency in this sense is equivalent to additive separability of the conditional probability distribution. Such separability structure is natural and can be exploited for efficient inference. Separability has a natural generalization to conditional separability. Separability provides a precise notion of hierarchical decomposition in temporal probabilistic models. Given a system that is decomposed into separable subsystems, exact marginal probabilities over subsystems at future points in time can be computed by propagating maxginal subsystem probabilities, rather than complete system joint probabilities. Thus, separability can make exact prediction tractable. However, observations can break separability, so exact monitoring of dynamic systems remains hard.
Correctness of component-based adaptation

Long running applications often need to adapt due to changing requirements or changing environment. Typically, such adaptation is performed by dynamically adding or removing components. In these types of adaptation, components are often added to or removed from multiple processes in the system. While techniques for such adaptations have been extensively discussed in the literature, there is a lack of systematic methods to ensure the correctness of dynamic adaptation. To redress this deficiency, in this paper, we propose a new method, based on the concept of proof lattice, for verifying correctness of dynamic adaptation in a distributed application. We use transitional-invariant lattice to verify correctness of adaptation. As an illustration of this method, we show how correctness of dynamic adaptation is obtained in the context of a message communication application.
The Cost Efficiency of Real Estate Investment Trusts: An Analysis with a Bayesian Stochastic Frontier Model

Using a stochastic frontier methodology that incorporates Bayesian statistics, this paper analyzes the cost efficiency of real estate investment trusts (REITs) by observing the deviations of the measured costs of individual REITs from a defined efficient cost frontier. Using 1995–1997 data, we extend the previous research in this area and measure REIT efficiency more precisely by isolating random measurement error from the overall deviations from the efficient cost frontier. We calculate the magnitude of each REIT's managerial inefficiency, the industry inefficiency, and returns to scale. In addition, we assess specific characteristics of REITs for their contribution to inefficiency by calculating the odds ratio that a REIT with a specific characteristic is more efficient than a REIT with an alternative characteristic. The results show that, for the years studied, REITs are relatively cost efficient with most REITs facing increasing returns to scale. Additionally, the REIT's use of debt and the REIT's management style significantly affect the cost performance of REITs during the aforementioned time period. Finally, diversification across property types, as measured, does not seem to influence REIT cost efficiency.
Does social security affect retirement and labor supply? : using the Chilean experience as an experiment

The paper explores the effects of the social security system over retirement and labor supply decision of individuals aged 55 to 65 in Chile. We use the 1998 CASEN survey elaborated by the Chilean government. Due to regulations established by the current social security law, two social security systems coexist on 1998: the .Pay-as-you-go. and the individual account system. This property of the dataset, allows us to disentangle the effects of those two systems over retirement and labor supply. The results show that social security may significantly affect retirement and labor supply decisions. The effects are mainly twofold. First, larger benefits may induce earlier retirement and lower labor supply and second, larger variance of benefits may induce later retirement and larger labor supply, due to a precautionary motive. This last effect seems to be important when analyzing the path of the Chilean retirement rates on the nineties.
Price roll-backs and path auctions: an approximation scheme for computing the market equilibrium

In this paper we investigate the structure of prices in approximate solutions to the market equilibrium problem. The bounds achieved allow a scaling approach for computing market equilibrium in the Fisher model. Our algorithm computes an exact solution and improves the complexity of previously known combinatorial algorithms for the problem. It consists of a price roll-back step combined with the auction steps of [11]. Our approach also leads to an efficient polynomial time approximation scheme. We also show a reduction from a flow problem to the market equlibrium problem, illustrating its inherent complexity.
On a Conjectured Formula for Quiver Varieties

In A.S. Buch and W. Fulton [i>Invent. i>Math. 135 (1999), 665–687] a formula for the cohomology class of a quiver variety is proved. This formula writes the cohomology class of a quiver variety as a linear combination of products of Schur polynomials. In the same paper it is conjectured that all of the coefficients in this linear combination are non-negative, and given by a generalized Littlewood-Richardson rule, which states that the coefficients count certain sequences of tableaux called factor sequences. In this paper I prove some special cases of this conjecture. I also prove that the general conjecture follows from a stronger but simpler statement, for which substantial computer evidence has been obtained. Finally I will prove a useful criterion for recognizing factor sequences.
Efficient Reachability Analysis of Hierarchical Reactive Machines

Hierarchical state machines is a popular visual formalism for software specifications. To apply automated analysis to such specifications, the traditional approach is to compile them to existing model checkers. Aimed at exploiting the modular structure more effectively, our approach is to develop algorithms that work directly on the hierarchical structure. First, we report on an implementation of a visual hierarchical language with modular features such as nested modes, variable scoping, mode reuse, exceptions, group transitions, and history. Then, we identify a variety of heuristics to exploit these modular features during reachability analysis. We report on an enumerative as well as a symbolic checker, and case studies.
Supply vs. Demand under an Affirmative Action Ban: Estimates from UC Law Schools

Affirmative action bans can reduce black enrollment not only by reducing black admission advantages (contracting demand) but also by reducing applications (contracting supply) from black students who can still gain admission but prefer alternative schools that still practice affirmative action. When affirmative action was banned at UC law schools, Berkeley's black applications and enrollment declined by almost half even as black admission rates rose relative to whites. I ask whether black enrollment at UC law schools would have markedly declined even if black supply had not contracted. I find in a large sample of students applying to law schools nationwide that black supply contractions were driven mostly or entirely by students unlikely to gain admission under the ban, yielding stronger post-ban black applicant pools. Holding applicant pools constant, I estimate that the ban reduced black admission rates at both Berkeley and UCLA by half. Hence, black enrollment would likely have plummeted even if black supply had not contracted—as could occur under a nationwide ban that eliminates affirmative-action-practicing alternatives.
An overview of HATS: a language independent high assurance transformation system

Transformations that are based on syntax directed rewriting systems can have a significant impact on the construction of high assurance systems. However, in order for a transformational approach to be useful to a particular problem domain, a (general) transformation system must be adapted to the notation of that particular domain. A transformation system that can be easily adapted to various domain notations has the potential of having a wide range of applicability. We discuss why transformation is attractive from a high assurance perspective, as well as some issues surrounding automated transformation within specific problem domains. We then give an overview of a language independent high assurance transformation system (HATS) that is being developed at Sandia National Laboratories.
Monotonicity and convexity of H/sup /spl infin// Riccati solutions in general case

State space formulas for H/sup /spl infin// optimal control problem involve two H/sup /spl infin// Riccati equations, whose solutions can be used to construct an optimal or suboptimal H/sup /spl infin// controller. This paper studies the existence of the solutions to the two H/sup /spl infin// Riccati equations in Glover-Doyle's formulation which is the most general one yet been considered, and shows that the solutions are nonincreasing convex functions in the domain of interest. The monotonicity and convexity of those H/sup /spl infin// Riccati solutions guarantee that the spectral radius of the product of those two Riccati solutions is also a nonincreasing convex function of /spl gamma/ in the domain of interest. According to these properties, a quadratically convergent algorithm is developed to compute the optimal H/sup /spl infin//.
Property as a Fundamental Constitutional Right? The German Example

INTRODUCTION 000 I. THE BASIC LAW, THE SOZIALSTAAT, AND THE “IMAGE OF MAN” .....000 II. ARTICLE 14 AND THE ROLE OF PROPERTY 000 A. Property and Self-Development 000 B. Property as Dynamic and Social: The “Social Obligation” of Ownership 000 III. THE SOURCE AND MEANING OF CONSTITUTIONAL PROPERTY ........000 A. The Basic Law as the Source of Constitutional Property: Environmental Regulation 000 B. The Substantive Meaning of Property in German Constitutional Law: Welfare Benefits 000 IV. NORMATIVE IMPLICATIONS OF THE GERMAN EXPERIENCE 000 A. Are Constitutional Property Clauses Inherently AntiRedistributive? 000 B. Should Property Be Treated as a Fundamental Constitutional Right Under the American Constitution? 000 CONCLUSION 000
iForensics: Forensic Analysis of Instant Messaging on Smart Phones

Smart phones with Internet capability are growing in popularity, due to many of their useful capabilities. Among other handy features of smart phones, Instant Messaging (IM) is very popular due to the level of convenience it provides in interpersonal communications. As the usage of IM on smart phone is increasing rapidly, it is important to take measures in advance from forensic standpoint forecasting the potential use of it in cyber crimes such as the cyber stalking and cyber bullying. Although, current IM applications for smart phones are in most cases a downsized version of the one used on traditional computers, diverse structure of file systems and storage device on different smart phones pose unique challenges to forensic examiners for recovering digital evidences of a conversation under investigation. In this work, we study and report the forensic analysis of three different IMs: AIM, Yahoo! Messenger and Google Talk, (both client based and web based version) on Apple iPhone. Our results show that the forensic analysis of IMs on smart phones has significant value and needs further attention.
Supercharacter Theories Constructed by the Method of Little Groups

The “method of little groups” describes the irreducible characters of semidirect products with abelian normal subgroups in terms of the irreducible characters of the factor groups. We modify this method to construct supercharacter theories of semidirect products with abelian normal subgroups. In particular, we apply this construction to reproduce known supercharacter theories of several families of unipotent groups. We also utilize our method to construct a collection of new supercharacter theories of the unipotent upper-triangular matrices.
The matrix orthogonal decomposition problem in intensity-modulated radiation therapy

In this paper, we study an interesting matrix decomposition problem that seeks to decompose a “complicated” matrix into two “simpler” matrices while minimizing the sum of the horizontal complexity of the first sub-matrix and the vertical complexity of the second sub-matrix. The matrix decomposition problem is crucial for improving the “step-and-shoot” delivery efficiency in Intensity-Modulated Radiation Therapy, which aims to deliver a highly conformal radiation dose to a target tumor while sparing the surrounding normal tissues. Our algorithm is based on a non-trivial graph construction scheme, which enables us to formulate the decomposition problem as computing a minimum s-t cut in a 3-D geometric multi-pillar graph. Experiments on randomly generated intensity map matrices and on clinical data demonstrated the efficiency of our algorithm.
Supply and Social Cost Estimates for Biomass from Crop Residues in the United States

The components of social costsincluded in the supply analysis are cashoutlays and opportunity costs associated withharvest and alternative residue uses, potentialenvironmental damage that is avoided byexcluding unsuitable land, and costs in movingresidues from farms to processing plants. Regional estimates account for the growingconditions and crops of the main agriculturalareas of the United States. Estimates includethe main U.S. field crops with potential forresidue harvest: corn, wheat, sorghum, oats,barley, rice and cane sugar. The potentialcontribution of residues to U.S. energy needsis discussed.
Development and applications of optical interferometric micrometrology in the Angstrom and subangstrom range

The recent development of the scanning electron tunneling microscope and the atomic force microscope requires absolute standards for measurements in the angstrom and subangstrom range. Optical interferometry with lasers and multiple mode laser resonances can provide absolute measurements as the laser wavelengths are very accurately known. A key feature of such measurements is the use of piezoelectric crystals as translators of the highest accuracy for very small disturbances. However, the dimensional changes of these crystals resulting from electrical potential changes depend on many variables, among them the method of mounting, so that accurate calibrations are necessary. Starting from advances in optical metrology made by physicists trying to find gravity waves, advances which led to measurements down to 10 to the -5 A, the author designed and built a much simpler system for the angstrom range. The major limiting factors were mechanical vibrations, air currents, thermal changes and laser instabilities.
War Everywhere: Rights, National Security Law, and the Law of Armed Conflict in the Age of Terror

INTRODUCTION: AN OUTMODED LEGAL PARADIGM 676 I. BACKGROUND 687 A. The Law of Armed Conflict 687 B. National Security Law 695 C. The Assumption of Clear Boundaries 702 II. CHANGES: GLOBALIZATION AND ASYMMETRICAL THREAT 705 III. THE BREAKDOWN OF BOUNDARIES 711 A. “International” Versus “Internal” Armed Conflicts 711 B. Crime Versus Conflict 715 C. Geographical Boundaries 720 D. War Without End: Temporal Boundaries 725 E. We Are All at War: Distinctions Between Persons 729 F. The Boundaries Between National Security and Domestic Affairs...... 736 IV. IMPLICATIONS: WAR EVERYWHERE; RIGHTS NOWHERE 744 V. WHAT CAN BE DONE? HUMAN RIGHTS LAW AS A BASIS FOR CRITIQUE 746 VI. REINVENTING THE LAW OF ARMED CONFLICT 755 CONCLUSION 760
On Explicit Reflection in Theorem Proving and Formal Verification

We show that the stability requirement for a verification system yields the necessity of some sort of a reflection mechanism. However, the traditional reflection rule based on the Godel implicit provability predicate leads to a "reflection tower" of theories which cannot be formally verified. We found natural lower and upper bounds on a metatheory capable of establishing stability of a given verification system. The paper also introduces an explicit reflection mechanism which can be veri fied internally. This circumvents the reflection tower and provides a theoretical justification for the verification process. On the practical side, the paper gives specific recommendations concerning verification of inference rules and building a verifiable reflection mechanism for a theorem proving system.
Possibilistic qualification and default rules

We discuss the problems involved in representing default knowledge. We suggest that default knowledge can be captured by using possibility qualified statements. We investigate the representation of possibility qualified statements via the theory of approximate reasoning. We apply our representation scheme to some examples. In particular, we show that this scheme gives reasonable results for a knowledge base in which we have "normally Quakers are pacifists" and "normally republicans are not pacifists".
A publish / subscribe based architecture of an alert server to support prioritized and persistent alerts

This paper discusses the design and development of a publish/subscribe based distributed alert server whose requirements include: priority-based delivery, persistence, recovery, time-to-live and various other features The approach described in this paper provides a lightweight implementation that is general-purpose and can be used for a number of applications A new efficient sweeping algorithm is used to make sure alerts are delivered correctly and satisfy several requirements such as priority, sending existing alerts to new subscribers, and regular expression based subscription.
Role of Alternative Assets in Portfolio Construction

This article discusses the role of nontraditional assets in constructing a portfolio for long-term investors. Alternative investments can provide novel patterns of returns and increase diversification benefits. In turn, investors can apply leverage in conjunction with wide diversification to improve their risk-adjusted performance. The concepts are illustrated via popular categories of alternative investments. We focus on long-term investors who are able to rebalance their portfolios on a regular basis. Careful risk management is critical in this domain. Keywords: alternative investments; portfolio management; diversification; fixed mix; re-balancing gain
Two-Photon Entanglement and Quantum Reality

Abstract One of the most surprising consequences of quantum mechanics is the entanglement of two or more distant particles. In 1935, Einstein-Podolsky-Rosen suggested the first classic two-particle entangled state, and proposed a gedanken-experiment . What was surprising about the EPR state and the outcome of the EPR gedankenexperiment is the following: The value of an observable for neither single particle is determined. However, if one of the particles is measured to have a certain value for that observable, the other one is 100% determined. A simple yet fundamental question was then asked by EPR: “Does a single particle have definite value for an observable, in the course of its travel, regardless of whether we measure it or not?” Quantum mechanics answers: “No.” EPR thought: “It should!” In 1964, J. S. Bell proofed a theorem to show that an inequality must be obeyed by any theories that subject to Einstein's local realism. It is this work that made possible the real-life experimental testing. The progression from gedanken to real experiment in recent years has been greatly aided by the use of Spontaneous Parametric Down Conversion (SPDC). The distinctive entanglement quantum nature of the resulting two-photon state of SPDC has allowed us to demonstrate the “spooky” EPR phenomenon as well as the violation of Bell's inequalities. In addition to reviewing several recent experiments, we introduce a new concept of “biphoton” in this chapter, which may be considered as a different approach to challenge the EPR puzzle.
Structural Analysis of U.S. Appraiser Income

This study represents the first investigation of appraiser income at the national level. It is especially timely because it addresses the value of Appraisal Institute designations in a post-FIRREA ...
Romer v. Evans and Invidious Intent

Notwithstanding numerous scholarly claims to the contrary, the Supreme Court's decision in Romer v. Evans was based on the invalidated law's impermissible purpose. Fourteenth Amendment doctrine is designed to ferret out unconstitutional intent. Such impermissible intent was evident in the law challenged in Romer. Nonetheless, Romer is a hard case, and its precedential significance is unclear, particularly in light of Bowers v. Hardwick, which upheld the constitutionality of laws against homosexual sodomy. Laws that facially disadvantage gays will always reflect both impermissible prejudice and permissible moral judgements.
Germany's economic ills

Horst Siebert is known internationally as the head of the prestigious Kiel Institute of World Economics and as a professor of economics at Kiel University. Professor Siebert is distinguished also by the breadth of his interest in the public policy issues in Europe in general and in Germany in particular. His comments on German policy are widely read and his position as a member of the German Council of Economic Advisers has given him an important voice in policy circles.
Introduction to Holographic Superconductors

These lectures give an introduction to the theory of holographic superconductors. These are superconductors that have a dual gravitational description using gauge/gravity duality. After introducing a suitable gravitational theory, we discuss its properties in various regimes: the probe limit, the effects of backreaction, the zero temperature limit, and the addition of magnetic fields. Using the gauge/gravity dictionary, these properties reproduce many of the standard features of superconductors. Some familiarity with gauge/gravity duality is assumed. A list of open problems is included at the end.
A new species of Carex section Abditispicae (Cyperaceae) from South America and additional notes on the section

Resumen en: Carex ruthsatzae of sect. Abditispicae (Cyperaceae) is newly described and illustrated from Bolivia. This species grows in high Andean moors, at elevati...
Simulating Plot: Towards a Generative Model of Narrative Structure

This paper explores the application of computer simulation techniques to the fields of literary studies and narratology by developing a model for plot structure and characterization. Using a corpus of 19th Century British novels as a case study, the author begins with a descriptive quantitative analysis of character names, developing a set of stylized facts about the way narratives allocate attention to their characters. The author shows that narrative attention in many novels appears to follow a “long tail” distribution.The author then constructs an explanatory model in NetLogo, demonstrating that basic assumptions about plot structure are sufficient to generate output consistent with the real novels in the corpus.
Investment Banking and Securities Issuance

This chapter analyzes the securities issuance process, focusing on initial public offerings (IPOs) and seasoned equity offerings (SEOs). The IPO literature documents three empirical patterns: 1) short-run underpricing; 2) long-run underperformance (although this is contentious); and 3) extreme time-series fluctuations in volume and underpricing. While the chapter mainly focuses on evidence from the USA, evidence from other countries is generally consistent with the USA patterns. A large literature explaining the short-run underpricing of IPOs exists, with asymmetric information models predominating. The SEO literature documents 1) negative announcement effects; 2) the setting of offer prices at a discount from the market price; 3) long-run underperformance; and 4) large fluctuations in volume. In addition to long-run underperformance relative to other stocks, there is some evidence that issuers succeed at timing their equity offerings for periods when future market returns are low. When examining a large class of corporate financing activities, including equity offerings, convertible bond offerings, bond offerings, open market repurchases, stock- and cash-financed mergers and acquisitions, and dividend increases or decreases, several patterns emerge. In general, the announcement effects are negative for activities that provide cash to the firm, and positive for activities that pay cash out of the firm. Furthermore, the market generally underreacts, in that long-run abnormal returns are usually of the same sign as the announcement effect. In spite of the large expenditure of resources on analyst coverage, there is little academic work emphasizing the importance of the marketing of financial securities. Only recently have papers begun to focus on the corporate financing implications if firms face variations in the cost of external financing due to the mispricing of securities by the market.
Spectra of Cayley graphs of complex reflection groups

Renteln proved that the eigenvalues of the distance matrix of a Cayley graph of a real reflection group with respect to the set of all reflections are integral and provided a combinatorial formula for some such spectra. We prove the eigenvalues of the distance, adjacency, and codimension matrices of Cayley graphs of complex reflection groups with connection sets consisting of all reflections are integral and provide a combinatorial formula for the codimension spectra for a family of monomial complex reflection groups.
Canonical Projective Embeddings of the Deligne–Lusztig Curves Associated to 2A2, 2B2, and 2G2

Canonical Projective Embeddings of the Deligne-Lusztig Curves Associated to 2 A 2 , 2 B 2 and 2 G 2 Daniel M. Kane May 15, 2015 Abstract The Deligne-Lusztig varieties associated to the Coxeter classes of the algebraic groups 2 A 2 , 2 B 2 and 2 G 2 are affine algebraic curves. We produce explicit projective models of the closures of these curves. Furthermore for d the Coxeter number of these groups, we find polynomials for each of these models that cut out the F q -points, the F q d -points and the F q d+1 - points, and demonstrate a relation satisfied by these polynomials. Introduction There are four kinds of finite groups of Lie type of rank 1. The associated Deligne-Lusztig varieties for the Coxeter classes of these groups all give affine algebraic curves. The completions of these curves have several applications in- cluding the representation theory of the associated group ([1, 5]), coding theory ([4]) and the construction of potentially interesting covers of P 1 ([3]). In this paper, we consider these curves associated to the groups G = 2 A 2 , 2 B 2 and 2 G 2 . The remaining curve is associated to G = A 1 and is P 1 , but we do not cover this case as it is easy and doesn’t follow many of the patterns found in the analysis of the other three cases. For each of these curves, we explicitly construct an embedding C ,→ P(W ) where W is a representation of G of dimension 3,5, or 14 respectively, and provide an explicit system of equations cutting out C. The curve associated to 2 A 2 is the Fermat curve. The curve associated to B 2 is also well-known though not immediately isomorphic to our embedding. Embeddings of the curve associated to 2 G 2 were not known until recently. In [6], they constructed an explicit curve with the correct genus, symmetry group and number of points. Later, in [2], Eid and Duursma use this description to independently arrive at the embedding we produce in this paper. ∗ University of California, San Diego, Department of Mathematics / Department of Computer Science and Engineering, 9500 Gilman Drive #0404, La Jolla, CA 92093 dakane@ucsd.edu
Path Integrals in the Physics of Lattice Polarons

A path-integral approach to lattice polarons is developed. The method is based on exact analytical elimination of phonons and subsequent Monte Carlo simulation of self-interacting fermions. The analytical basis of the method is presented with emphasis on visualization of polaron effects, which path integrals provide. Numerical results on the polaron energy, mass, spectrum and density of states are given for short-range and long-range electron-phonon interactions. It is shown that certain long-range interactions significantly reduce the polaron mass, and anisotropic interactions enhance polaron anisotropy. The isotope effect on the polaron mass and spectrum is discussed. A path-integral approach to the Jahn-Teller polaron is developed. Extensions of the method to lattice bipolarons and to more complex polaron models are outlined.
The Distribution of Totients

This paper is a comprehensive study of the set of totients, i.e., the set of values taken by Euler's φ-function. The main functions studied are V(x), the number of totients ≤x, A(m), the number of solutions of φ(x)=m (the “multiplicity” of m), and V_k(x), the number of m ≤ x with A(m)=k. The first of the main results of the paper is a determination of the true order ofV(x) . It is also shown that for each k ≥ 1, if there is a totient with multiplicity k then V_k(x) ≫ V(x). Sierpinski conjectured that every multiplicity k ≥ 2 is possible, and we deduce this from the Primek -tuples Conjecture. An older conjecture of Carmichael states that no totient has multiplicity 1. This remains an open problem, but some progress can be reported. In particular, the results stated above imply that if there is one counterexample, then a positive proportion of all totients are counterexamples. The lower bound for a possible counterexample is extended to $$10 10 10 $$ and the bound lim inf_x→ ∞} V_1(x)/V(x) ≤ 10-5,000,000,000 is shown. Determining the order of V(x) and V_k(x) also provides a description of the “normal” multiplicative structure of totients. This takes the form of bounds on the sizes of the prime factors of a pre-image of a typical totient. One corollary is that the normal number of prime factors of a totient ≤x is c log log x, where c≈2.186. Lastly, similar results are proved for the set of values taken by a general multiplicative arithmetic function, such as the sum of divisors function, whose behavior is similar to that of Euler's function.
The X-ray Spectrum of the Jets in the SS 433 System Using the Chandra HETGS

Observations of SS 433 using the Chandra High Energy Transmission Grating Spectrometer are presented. Many lines of highly ionized elements are detected; all are detectably broadened by 2000–5000 km s−1 and the widths do not depend significantly on the characteristic emission temperature, suggesting that the emission occurs in a freely expanding region of constant collimation. Line ratios show that the base temperature of the jet is below 10 keV and may be closer to 2.5 keV. The X-ray luminosity during this observation was somewhat lower than average, which may be related to the lower jet temperature. The blue shifts of lines from low temperature gas are the same as those of high temperature gas, indicating that jet acceleration occurs closer to the compact object than ∼2 × 1011 cm, where the emission lines originate. The image from zeroth order shows extended emission at a scale of ∼2′, aligned in the direction of the radio jets.
Chiral Symmetry Outside Perturbation Theory

Within the overlap framework, I derive the main formulae one finds today in papers touting a “new approach” to the regularization of chiral gauge theories. My main objective is to clear up an unhealthy confusion about how many successful approaches to regulate chiral fermions on the lattice there really are: At the moment, there is only one, the overlap, and finding a genuinely different approach is an important and completely open problem.
Cyber-Security for the Controller Area Network (CAN) Communication Protocol

We propose a security mechanism to help prevent cyber-attacks (masquerade and replay) in vehicles with architecture based on Controller Area Network (CAN). We focus on CAN as it will likely continue being used in upcoming in-vehicle architectures. The CAN protocol contains no direct support for secure communications. Retrofitting the protocol with security mechanisms poses several challenges given the very limited data rates available (e.g., 500kbps) since bus utilization may significantly increase. In this paper, we focus on a security mechanism which keeps the bus utilization as low as possible. Through our experimental results, we show that our security mechanism can achieve high security levels while keeping communication overheads (e.g., bus load and message latency) at reasonable levels.
Low-lying zeros of families of elliptic curves

The random matrix model predicts that many statistics associated to zeros of a family of L-functions can be modeled (or predicted) by the distribution of eigenval ues of large random matrices in one of the classical linear groups. If the statistics of a family of L-functions are modeled by the eigenvalues of the group G, then we say that G is the symmetry group (or symmetry type) associated to the family. The statistic of interest to us in this work is the density of zeros near the central point (also known as the 1-level density). The random matrix model predicts that the distribution of these zeros should be modeled by the eigenvalues nearest 1 for one of the symmetry types G (unitary, symplectic, and orthogonal). All of the different groups G have distinct behavior in this regard. Therefore, computing the 1-level density gives a theoretical way to predict the symmetry type of a family. The 1-level density has been studied for a wide variety of families of L-functions; see [R], [KSI], [ILS], [Mil] for example. It is standard to assume the Generalized Riemann Hypothesis (GRH) to study the 1-level density and we do so throughout this work. In particular, it is necessary to use GRH for the application of obtaining a bound on the average analytic rank from a density theorem. In some cases the use of GRH improves the range of the density theorem, which translates to an improved bound on the average rank. Besides these crucial applications of GRH, we have freely assumed GRH even when it could be removed with extra work since it simplifies arguments in some non essential places. It is especially interesting to investigate the 1-level density for families of L functions attached to elliptic curves over the rationals since zeros at the central point have important arithmetic information (by the conjecture of Birch and Swinnerton Dyer). These investigations have been the main focus of this work.
Annotation graphs and servers and multi-modal resources: infrastructure for interdisciplinary education, research and development

Annotation graphs and annotation servers offer infrastructure to support the analysis of human language resources in the form of time-series data such as text, audio and video. This paper outlines areas of common need among empirical linguists and computational linguists. After reviewing examples of data and tools used or under development for each of several areas, it proposes a common framework for future tool development, data annotation and resource sharing based upon annotation graphs and servers.
Molecular Mechanisms of IL-2 Gene Regulation Following Costimulation Through LFA-1

The integrin LFA-1 serves as an accessory molecule in T cell activation. In addition to its well-known role as an adhesion molecule, LFA-1 can contribute to T cell activation and up-regulation of IL-2 gene expression. However, the specific mechanisms by which LFA-1 influences T cell activation have not been elucidated. Therefore, we examined the impact of LFA-1:ICAM-1 interactions on transcriptional and posttranscriptional IL-2 gene regulation, using a costimulation-negative cell line transfected with MHC class II alone, or in combination with ICAM-1 or B7-1. IL-2 transcription was assessed utilizing transgenic mice expressing an IL-2 promoter luciferase reporter construct crossed to DO11.10 TCR-transgenic mice, and IL-2 mRNA stability was evaluated by real-time RT-PCR. Comparison of naive and previously activated T cells demonstrates a dramatic increase in IL-2-luciferase transcription in activated T cells that can, in part, be attributed to downstream signaling events. Costimulation through LFA-1 enhances transcription of the transgenic reporter construct across a wide Ag dose range, but does not affect IL-2 mRNA stability. In contrast, CD28 costimulation is clearly mediated through up-regulation of IL-2 transcription and through enhancement of mRNA stability. These results indicate that the primary pathway whereby engagement of LFA-1 through its ligand ICAM-1 up-regulates IL-2 gene expression is through enhanced IL-2 transcription, in the absence of any effect on IL-2 mRNA stabilization.
Low frequency electrical properties of selected dielectrics

It seems that each material had its own individual behavior and no generalized rules can be formulated from the data. For our own purposes the phenolic (curve 7) came closest to satisfy our requirement of a dissipation factor of unity. For any other specific use the material should be tested as close to the expected operating conditions as possible in view of the presently existing unpredictability of electrical behavior.
TLS Proxies: Friend or Foe?

We measure the prevalence and uses of TLS proxies using a Flash tool deployed with a Google AdWords campaign. We generate 2.9 million certificate tests and find that 1 in 250 TLS connections are TLS-proxied. The majority of these proxies appear to be benevolent, however we identify over 1,000 cases where three malware products are using this technology nefariously. We also find numerous instances of negligent, duplicitous, and suspicious behavior, some of which degrade security for users without their knowledge. Distinguishing these types of practices is challenging in practice, indicating a need for transparency and user awareness.
Chromosome abnormalities in leukemia.

The renewed interest in the study of chromosome abnormalities in hematologic malignancies, particularly in the leukemias, is the result of technical improvements which permit the precise identification of each human chromosome, and of parts of chromosomes as well. The information obtained raises a number of questions regarding the validity of older notions, such as the variability of the chromosome pattern (karyotype) in acute leukemia, or the rarity of associations of specific chromosome abnormalities with particular types of leukemia. One of the surprising observations of the last few years has been the frequent occurrence of consistent translocations in a variety of hematologic malignancies. The challenging questions at present are how and why nonrandom changes, particularly consistent translocations, occur.
MR signal abnormalities in memory disorder and dementia.

MR imaging of the brain, performed in 86 normal subjects and 113 patients with objective memory disorder or dementia, demonstrated white- and gray-matter areas of high signal intensity on long TR images (short and long TE). Hyperintensities were analyzed with respect to size (on a scale of 0-3) and location: lesions were periventricular, subcortical, or cortical. The patients with memory disorder and dementia were categorized as having probable/possible Alzheimer disease, a combination of Alzheimer disease and multiinfarct cognitive disorder, or multiinfarct cognitive disorder alone on the basis of clinically determined Hachinski ischemic scores. Significant correlations were found between age and scores for periventricular lesions (r = .40, p less than .0005) and subcortical lesions (r = .39, p less than .0005) in normal subjects. Correlations were also found between the Hachinski ischemic score and scores for periventricular lesions (r = .21, p less than .01), subcortical lesions (r = .27, p less than .0002), and cortical lesions (r = .32, p less than .0005) in subjects with memory disorder/dementia. Comparing multiinfarct cognitive disorder, Alzheimer disease, and normal groups, the mean scores for periventricular lesions were 12.0 +/- 4.6, 7.6 +/- 4.8, and 3.4 +/- 2.6, while mean scores for subcortical lesions were 10.8 +/- 12.2, 4.1 +/- 6.4, and 0.8 +/- 1.2, respectively. Periventricular lesions were present in 99-100% of patients with Alzheimer disease and multiinfarct cognitive disorder. On the other hand, subcortical lesions, which were identified in 100% of patients with multiinfarct cognitive disorder, were present in only about half of the patients with Alzheimer disease.(ABSTRACT TRUNCATED AT 250 WORDS)
Approximations of random dispersal operators/equations by nonlocal dispersal operators/equations

Abstract This paper concerns the approximations of random dispersal operators/equations by nonlocal dispersal operators/equations. It first proves that the solutions of properly rescaled nonlocal dispersal initial–boundary value problems converge to the solutions of the corresponding random dispersal initial–boundary value problems. Next, it proves that the principal spectrum points of nonlocal dispersal operators with properly rescaled kernels converge to the principal eigenvalues of the corresponding random dispersal operators. Finally, it proves that the unique positive time periodic solutions of nonlocal dispersal KPP equations with properly rescaled kernels converge to the unique positive time periodic solutions of the corresponding random dispersal KPP equations.
The interactions of solitons in the Novikov–Veselov equation

Using the reality condition of the solutions, one constructs the real Pfaffian N-solitons solutions of the Novikov–Veselov (NV) equation using the function and the Schur identity. By the minor-summation formula of the Pfaffian, we can study the interactions of solitons in the NV equation from the Kadomtsev–Petviashvili (KP) equation’s point of view, that is, the totally non-negative Grassmannian. Especially, the Y-type resonance, O-type, and the P-type interactions of X-shape are investigated. Also, the maximum amplitude of the intersection of the line solitons and the critical angle is computed. In addition, one makes a comparison with the KP-(II) equation.
Violations of the Born rule in cool state-dependent horizons

The black hole information problem has motivated many proposals for new physics. One idea, known as state-dependence, is that quantum mechanics must be generalized to describe the physics of black holes, and that fixed linear operators do not provide the fundamental description of experiences for infalling observers. Instead, such experiences are to be described by operators with an extra dependence on the global quantum state. By generalizing a previous argument for firewalls in generic black holes, we show that any implementation of this idea strong enough to remove firewalls from generic states requires massive violations of the Born rule. We also demonstrate a sense in which such violations are visible to infalling observers involved in preparing the initial state of the black hole. We emphasize the generality of our results; no details of any specific proposal for state-dependence are required.
The Revivalism of Narrative: A Response to Recent Criticisms of Quantitative History

In his presidential address to the Social Science History Association Convention in November 1981, Robert William Fogel declared sanguinely that social scientific historians had won their battle for legitimacy within the historical profession in America, and that we should now stop feeling embattled, spend less effort proselytizing, and calmly go on with our substantive work. While his statistics on the occupational advancement of social scientific historians do indicate a degree of acceptance, and while his advice to worry less and pay attention to business will be followed (as that is what nearly all of us were doing anyway), I am less optimistic than Fogel, read the employment trends differently, and see more signs of a reaction against quantitative social scientific history-or what I like to refer to as QUASSH-than he does (Kousser, 1980). Perhaps Professor Fogel and I differ only temperamentally. As a former Marxist, he still retains a bit of faith in the inevitable triumph of progressive forces; as a former Methodist, I am unable to shake off the pessimism that is the psychological residue of the doctrine of original sin. In any case, whereas Fogel seems to think that most recent criticisms of QUASSH are so obviously flawed as to require no answer, I fear that some people, especially those with substantial investments in "history-as-it-used-to-be-done," may still be susceptible to false messiahs or, perhaps more precisely, false Jeremiahs.
Mobile Agents - The Right Vehicle for Distributed Sequential Computing

Distributed sequential computing (DSC) is computing with distributed data using a single locus of computation. In this paper we argue that computation mobility--the ability for the locus of computation to migrate across distributed memories and continue the computation as it meets the required data--facilitated by mobile agents with strong mobility is essential for scalable distributed sequential programs that preserve the integrity of the original algorithm.