cssi/SciSciGPT-SciSciNet huggingface dataset:
The Microstructure Approach to Exchange Rates

Historically, the fields of exchange-rate economics and microstructure finance have progressed independently of each other. Recent interaction, however, has given rise to a microstructure approach to exchange rates. This book focuses on the economics of financial information and how microstructure tools help to clarify the types of information most relevant to exchange rates. The microstructure approach views exchange rates from the perspective of the trading room, the place where exchange rates are actually determined. Emphasizing information economics over institutional issues, the approach departs from three unrealistic assumptions common to previous approaches: that all information relevant to exchange rates is publicly available, that all market participants are alike in their goals or in how they view information, and that how trading is organized is inconsequential for exchange rates. The book shows how exchange-rate behavior previously thought to be particularly puzzling can be explained using the microstructure approach. It contains a combination of theoretical and empirical work.
The Deadweight Loss of Coupon Remedies for Price Overcharges

Consumers injured by price overcharges often are awarded coupons that can be used for a limited period of time to purchase the good at a price below that which prevails after the overcharge has been eliminated. Coupon remedies cause a deadweight loss by inducing excessive consumption by consumers with relatively low demand during the remedy period. The magnitude of the loss can be comparable to that caused by the price overcharge. As demand variability goes to zero, the deadweight loss from coupon remedies goes to zero. Eliminating the expiration date for the use of coupons does not eliminate the loss.
Quantum Spin Systems

Thetheory ofquantumspinsystems isconcernedwith properties of quantum systems with an in-ﬁnite number of degrees of freedom that eachhave a ﬁnite-dimensional state space. Occasion-aly, oneis speciﬁcally interested in ﬁnitesystems.In the most common examples one has an n-dimensional Hilbert space associated with eachsite of a d-dimensional lattice.A model is normally deﬁned by describinga Hamiltonian or a family of Hamiltonians,which are self-adjoint operators on the Hilbertspace, and one studies their spectrum, the eigen-states, the equilibrium states, its dynamics, non-equilibrium stationary states etc.More particularly, the term “quantum spinsystem” often refers to such models where eachdegree of freedom is thought of as a spin variable,i.e., there are three basic observables represent-ing the components of the spin, S
Does Uncertainty Matter: An Application to the Willingness to Pay to Reduce Swimming Bans in Chicago

Using a survey of Chicago beachgoers, this research examines the effect of uncertain response options on the willingness to pay to reduce swimming bans. Various recoding options are tested and implemented, as well as multinomial model for choice. Estimates are compared to those from a dataset with certainty, as well as to those from revealed preference methods. The reasons and sources for uncertainty are explored and compared across samples.
Bandwidth Efficient Parallel Computation

We believe that for the next few years, the most pressing research question in parallel computation will concern communication bandwidth: Can we design fast algorithms for parallel computers that only support low bandwidth communication (such as most existing parallel computers). An alternative formulation of the question is, can we design parallel algorithms that have communication locality? While good locality preserving techniques are known for application problems with regular, predictable dataflow, few theoretical results have been developed for irregular problems e.g. problems involving sparse graphs, or problems that adapt to data distribution dynamically. And yet, since most existing parallel computers only offer low communication bandwidth, it is necessary to either develop techniques to live with low bandwidth, or provide arguments in favor of building parallel computers with high bandwidth communication systems.
Modeling Certainty-Adjusted Willingness to Pay for Ecosystem Service Improvement from Agriculture

The public demand for ecosystem services measured by willingness to pay (WTP) in contingent valuation studies provides important information for designing Payment-for-Ecosystem-Service (PES) programs. However, the hypothetical markets for contingent valuation and respondents’ unfamiliarity with certain ecosystem services may increase their preference uncertainty, which may increase variance and even cause bias in WTP estimates. Taking advantage of a unique stated preference data set that includes a follow-up question rating the respondent’s certainty level, this study evaluates alternative methods of modeling certainty-adjusted WTP for cleaner lakes and abated global warming. Results suggest that the incorporation of self-reported uncertainty into binary choice models significantly reduces the median WTP and appears to improve our understanding of the demand for ecosystem services.
Deposit Insurance: Actual and Good Practices

This paper demonstrates a well-designed deposit guarantee system can strengthen incentives for owners, managers, depositors and other creditors, borrowers, regulators and supervisors, and politicians. Borrowers should be aware that they will have to repay their loans if their bank fails and will be encouraged to keep their loans current where offsetting is limited to past-due loans. The performance of insurers, regulators, and supervisors as agents will improve where they know that they can take justifiable actions without political interference and will be held accountable for their actions to their principals. Despite the improvements, and possibly partly because there are issues in deposit insurance design that remain to be resolved, financial crises have been prevalent during the 1990s. This situation has forced a number of countries to offer a blanket guarantee to restore confidence and to allow the continued functioning of the financial system while the authorities take time to design a plan for the resolution of the crisis.
Decoupling, exponential sums and the Riemann zeta function

We establish a new decoupling inequality for curves in the spirit of [B-D1], [B-D2] which implies a new mean value theorem for certain exponential sums crucial to the Bombieri-Iwaniec method as developed further in [H]. In particular, this leads to an improved bound $|\zeta(\frac 12+it)|\ll t^{53/342+\varepsilon}$ for the zeta function on the critical line
Unsupervised Learning of Morphology Without Morphemes

The first morphological learner based upon the theory of Whole Word Morphology (Ford et al., 1997) is outlined, and preliminary evaluation results are presented. The program, Whole Word Morphologizer, takes a POS-tagged lexicon as input, induces morphological relationships without attempting to discover or identify morphemes, and is then able to generate new words beyond the learning sample. The accuracy (precision) of the generated new words is as high as 80% using the pure Whole Word theory, and 92% after a post-hoc adjustment is added to the routine.
Ultrafast-electron dynamics and recombination on the Ge(111)(2×1) π-bonded surface

Angle-resolved laser-photoemission spectroscopy has been used to study the ultrafast-electron scattering and recombination processes on the Ge(111) \ensuremath{\pi}-bonded (2\ifmmode\times\else\texttimes\fi{}1) surface with subpicosecond time resolution. Electrons photoexcited into the bulk Ge conduction band scatter into the unoccupied surface antibonding ${\mathrm{\ensuremath{\pi}}}^{\mathrm{*}}$ band whose minimum is at the J\ifmmode\bar\else\textasciimacron\fi{} point in the surface Brillouin zone. Rapid relaxation to the surface-band minimum is followed by a unique phonon-assisted process in which electrons recombine with bulk holes at the valence-band maximum, which we find to be the primary mechanism responsible for the decay of the transient ${\mathrm{\ensuremath{\pi}}}^{\mathrm{*}}$ population. Time-dependent measurements carried out at 300 and 120 K have been employed to determine the role of energetic phonons in the scattering processes. These processes are modeled with a set of rate equations, whose fits to the data yield scattering times used to determine a surface recombination velocity directly. Ultrafast surface-state hole dynamics are observed, and a renormalization of the surface band gap is studied as a function of electron density. The \ensuremath{\pi}-bonded states are fundamentally one dimensional in nature, and thus these results represent studies of band-gap renormalization in a one-dimensional system.
North of the Colour Line: Sleeping Car Porters and the Battle Against Jim Crow on Canadian Rails, 1880-1920

This paper analyses the evolution of Jim Crow employment patterns in the Canadian railway industry from the 1880s to World War I. It presents race as acentral organizing principle in employers' decision to hire black railwaymen for their sleeping and dining car departments. Canadian railway managers actively sought out African American, West Indian, and African Canadian labour, believing that they constituted an easily manipulated group of workers. White railroaders fought the introduction of black employees, arguing that they undermined white manhood and railway unionism. Trade union leaders demanded and won a racialized division of the workforce, locking black workers into low-waged service position when they had initially enjoyed a broader range of employment options. In effect, white railway trade unionists and their employers embraced segregation as a rational model for peaceful working conditions. Black railroaders, on the other hand, resisted the encroachment of segregationist policies by forming their own union, the Order of Sleeping Car Porters. They pressured for change by exposing the scope of Jim Crow practices in the railway industry and trade unionism. Resume Cet article analyse l'evolution des modeles d'emploi de Jim Crow dans l'industrie des chemins de fer canadiens des annees 1880 jusqu'a la Premiere Guerie Mondiale. Il presente la race comme un principe fondamental dans la decision des employeurs d'embaucher des travailleurs noirs pour les wagons-lits et les wagons-restaurants. Les chefs des chemins de fer canadiens recherchaient activement les Afro-Americains, les Antillais et les Afro-Canadiens, en pensant qu'ils faisaient partie d'un groupe de travailleurs faciles a manipuler. Les travailleurs blancs se sont battus contre l'embauche des employes noirs, en disant que ces derniers saperaient leur virilite et le syndicalisme aux chemins de fer. Les chefsdes syndicats ont demande et gagne une separation de la main-d'oeuvre selon larace, confinant les travailleurs noirs aux emplois peu remuneres alors qu'ils avaient initialement une gamme de possibilites d'emploi plus variee. En effet, les syndicalistes blancs et les employeurs ont soutenu la segregation comme modele rationnel des conditions de travail pacifiques. Les travailleurs noirs, en revanche, ont resiste aux politiques de segregation en formant leur propre syndicat, l'Ordre des travailleurs de wagons-lits. Ils ont fait des pressions pour obtenir des changements en rendant publiques les pratiques de Jim Crow dans l'industrie des chemins de fer et dans le mouvement syndical.
Research and development of optical measurement techniques for aerospace propulsion research: A NASA Lewis Research Center perspective

The applied research effort required to develop new nonintrusive measurement techniques capable of obtaining the data required by aerospace propulsion researchers and of operating in the harsh environments encountered in research and test facilities is discussed and illustrated through several ongoing projects at NASA's Lewis Research Center. Factors including length of development time, funding levels, and collaborative support from fluid-thermal researchers are cited. Progress in developing new instrumentation via a multi-path approach, including NASA research, grant, and government-sponsored research through mechanisms like the Small Business Innovative Research program, is also described.
On quadratization of pseudo-boolean functions

Set functions, i.e., real mappings form the family of subsets of a finite set to the reals are known and widely used in discrete mathematics for almost a century, and in particular in the last 50 years. If we replace a finite set with its characteristic vector, then the same set function can be interpreted as a mapping from the set of binary vectors to the reals. Such mappings are called pseudo-Boolean functions and were introduced in the works of Peter L. Hammer in the 1960s, see the seminal book (Hammer and Rudeanu 1968). PseudoBoolean functions are different from set functions, only in the sense that their algebraic representation, a multilinear polynomial expression, is usually assumed to be available as an input representation:
The Solar Dynamo

The solar dynamo is the process by which the Sun's magnetic field is generated through the interaction of the field with convection and rotation. In this, it is kin to planetary dynamos and other stellar dynamos. Although the precise mechanism by which the Sun generates its field remains poorly understood in spite of decades of theoretical and observational work, recent advances suggest that solutions to this solar dynamo problem may be forthcoming. The two basic processes involved in dynamo activity are demonstrated and the Sun's activity effects are presented in this document, along with a historical perspective regarding solar dynamos and the efforts to understand and measure them.
High Energy Neutrino Astronomy: Towards Kilometer-Scale Detectors

After three decades of anticipation two high energy neutrino telescopes are taking data: one deployed in the clear deep waters of Lake Baikal, the other in the transparent Antarctic ice sheet under the geographic South Pole. Neutrinos from the Lake Baikal detector bode well for the flurry of R&D activities leading to the deployment of similar instruments in the Mediterranean. The AMANDA telescope announced first light, neutrinos actually. It is a telescope in the 104 m2 class envisaged by the DUMAND collaboration, and is producing results that validate plans for commissioning a kilometer-scale detector in Antarctic ice. Although high energy neutrino astronomy is a multidisciplinary science, gamma ray bursts and supermas-sive black holes have become its theoretical focus since recent astronomical observations revealed their potential as cosmic particle accelerators. These astronomical highlights are shared with particle physics, especially the potential of high energy telescopes to observe oscillating neutrinos. The recent Superkamiokande results have boosted atmospheric neutrinos from a calibration tool and a background for doing astronomy, to an opportunity to confirm the evidence for neutrino mass.
Numerical calculation of transonic flow past a swept wing by a finite volume method

The finite volume method for the numerical calculation of transonic flow past a swept wing was developed and its use for calculating the pressure distribution on the upper surface of a Onera m6 wing in Mach No. 0.84 flow and of a Douglas DC10 wing in M = 0.85 flow is illustrated. Calculated results are compared with experimental data. The results confirm the promise of the new method. It appears that it can be used to treat configurations of more or less arbitrary complexity, subject to limits set by the power of the available computers. The extension to new configurations is primarily a matter of devising mesh generating schemes, since the internal computations are essentially independent of the configuration, apart from the identification of which elements are the boundary elements. (LCL)
Towards flexible teamwork

Many AI researchers are today striving to build agent teams for complex, dynamic multi-agent domains, with intended applications in arenas such as education, training, entertainment, information integration, and collective robotics. Unfortunately, uncertainties in these complex, dynamic domains obstruct coherent teamwork. In particular, team members often encounter differing, incomplete, and possibly inconsistent views of their environment. Furthermore, team members can unexpectedly fail in fulfilling responsibilities or discover unexpected opportunities. Highly flexible coordination and communication is key in addressing such uncertainties. Simply fitting individual agents with precomputed coordination plans will not do, for their inflexibility can cause severe failures in teamwork, and their domain-specificity hinders reusability. Our central hypothesis is that the key to such flexibility and reusability is providing agents with general models of teamwork. Agents exploit such models to autonomously reason about coordination and communication, providing requisite flexibility. Furthermore, the models enable reuse across domains, both saving implementation effort and enforcing consistency. This article presents one general, implemented model of teamwork, called STEAM. The basic building block of teamwork in STEAM is joint intentions (Cohen & Levesque, 1991b); teamwork in STEAM is based on agents' building up a (partial) hierarchy of joint intentions (this hierarchy is seen to parallel Grosz & Kraus's partial Shared-Plans, 1996). Furthermore, in STEAM, team members monitor the team's and individual members' performance, reorganizing the team as necessary. Finally, decision-theoretic communication selectivity in STEAM ensures reduction in communication overheads of teamwork, with appropriate sensitivity to the environmental conditions. This article describes STEAM's application in three different complex domains, and presents detailed empirical results.
A Numerical Study of Shock Wave Refraction at a CO2/CH4 Interface

This paper describes the numerical computation of a shock wave refracting at a gas interface. We study a plane shock in carbon dioxide striking a plane gas interface between the carbon dioxide and methane at angle of incidence α i . The primary focus here is the structure of the wave system as a function of the angle of incidence for a fixed (weak) incident shock strength. The computational results agree well with the shock polar theory for regular refraction including accurately predicting the transition between a reflected expansion and a reflected shock. They also yield a detailed picture of the transition from regular to irregular refraction and the development of a precursor wave system. In particular, the computations indicate that for the specific case studied the precursor shock weakens to become a band of compression waves as the angle of incidence increases in the irregular regime.
Black hole-neutron star binary merger calculations: GRB progenitors and the stability of mass transfer

We have calculated the first dynamical evolutions of merging black hole‐neutron star binaries that treat the combined spacetime in a nonperturbative general relativistic framework. Using the conformal flatness approximation, we have studied how the location of the tidal disruption radius with respect to the the black hole horizon and innermost stable circular orbit (ISCO) affects the qualitative evolution of the system. Based on simple arguments, we show that for a binary mass ratio q ≳ 0.24, tidal disruption occurs outside the ISCO, while the opposite is true for q ≲ 0.24. When tidal disruption occurs sufficiently far outside the ISCO, mass is transferred unstably from the neutron star to the black hole, resulting in the complete disruption of the neutron star. When tidal disruption occurs slightly within the ISCO, we find that some of the mass forms an extremely hot disk around the black hole. The resulting configurations in this case are excellent candidates for the progenitors of short‐hard gamma ray bursts.
Risks in pensions and annuities : efficient designs

This paper considers alternatives to disperse the accumulated pension rights during the liquidation phase or retirement. First, the paper classifies the risks that affect pensioners, discusses the defined benefit and defined contribution options, and classifies pension contracts according to the type of risk they transfer to worker. It considers fixed annuities, variable annuities, CREF annuities, and programmed withdrawal. This part is a description of the production function for pensions and annuities. Second, the paper offers a discussion of the restrictions that should be imposed by mandatory pension systems on the menu of pension contracts. One section discusses whether lump sum withdrawals should be allowed and the other discusses if there should be a mandate to annuitize wealth. The argument that the annuitization should be mandated to prevent adverse selection is rejected on the basis of Chilean evidence.
Gromov invariants for holomorphic maps from Riemann surfaces to Grassmannians

Two compactifications of the space of holomorphic maps of fixed degree from a compact Riemann surface to a Grassmannian are studied. It is shown that the Uhlenbeck compactification has the structure of a projective variety and is dominated by the algebraic compactification coming from the Grothendieck Quot Scheme. The latter may be embedded into the moduli space of solutions to a generalized version of the vortex equations studied by Bradlow. This gives an effective way of computing certain intersection numbers (known as “Gromov invariants”) on the space of holomorphic maps into Grassmannians. We carry out these computations in the case where the Riemann surface has genus one. Department of Mathematics, University of Utah, Salt Lake City, Utah 84112 E-mail address: bertram@math.utah.edu Department of Mathematics, Brown University, Providence, Rhode Island 02912 E-mail address: daskal@gauss.math.brown.edu Department of Mathematics, University of California, Irvine, California 92717 E-mail address: raw@math.uci.edu License or copyright restrictions may apply to redistribution; see http://www.ams.org/journal-terms-of-use
A new proof of Kunen’s inconsistency

Using elementary pcf, we show that there is no $j:V\to M,$ $M$ transitive, $j\lambda =\lambda >crit(j),$ $j^{\prime \prime}\lambda \in M.$
Comparison and Renaissance of Classic Line-of-balance and Linear Schedule Concepts for Construction Industry☆

Abstract Line-of-Balance (LOB) is a useful analytical tool for repetitive activities in construction projects, which allows showing which crew is assigned to what repetitive work unit of an activity. LOB is closely related to the linear scheduling method, but possesses some challenges: It must be clarified how it counts, as previous studies displayed an apparent measurement gap at the origin, implicitly representing that LOB starts at the first unit finish. Slopes in linear scheduling and LOB are different, even though both portray a measure of progress of an activity. This paper therefore tracks evolution and current use of LOB versus linear schedules. Its contribution to the body of knowledge is threefold: First, based on a literature review, LOB is found to be rooted in Activity-on-Arrow (AOA) diagrams, which makes it event-centered, not progress-centered. Differences in representing the start and productivity between LOB and linear scheduling are reviewed and explained both mathematically and graphically. Second, different LOB concepts are extracted and assessed to facilitate comparing LOB from its original use in manufacturing against the limited application of its objective chart in the construction industry. Third, a mathematical formulation based on singularity functions is developed, which can model staggering, continuity, and interruptability scenarios.
Batch Normalization: Accelerating Deep Network Training by Reducing Internal Covariate Shift

Training Deep Neural Networks is complicated by the fact that the distribution of each layer's inputs changes during training, as the parameters of the previous layers change. This slows down the training by requiring lower learning rates and careful parameter initialization, and makes it notoriously hard to train models with saturating nonlinearities. We refer to this phenomenon as internal covariate shift, and address the problem by normalizing layer inputs. Our method draws its strength from making normalization a part of the model architecture and performing the normalization for each training mini-batch. Batch Normalization allows us to use much higher learning rates and be less careful about initialization, and in some cases eliminates the need for Dropout. Applied to a state-of-the-art image classification model, Batch Normalization achieves the same accuracy with 14 times fewer training steps, and beats the original model by a significant margin. Using an ensemble of batch-normalized networks, we improve upon the best published result on ImageNet classification: reaching 4.82% top-5 test error, exceeding the accuracy of human raters.
Optimal Solutions for a Class of Point Retrieval Problems

Let P be a set of n points in the Euclidean plane and let C be a convex figure. We study the problem of preprocessing P so that for any query point q, the points of P in C + q can be retrieved efficiently. If constant time suffices for deciding the inclusion of a point in C, we then demonstrate the existence of an optimal solution: the algorithm requires O(n) space and O(k + log n) time for a query with output size k. If C is a disk, the problem becomes the well-known fized radius neighbor problem, to which we thus provide the first known optimal solution.
Maximum lifetime broadcasting in wireless networks

Summary form only given. We consider the problem of broadcasting messages in a wireless energy-limited network so as to maximize network lifetime. An O(e log e) algorithm to construct a broadcast tree that maximizes the critical energy of the network following the broadcast is developed. Additionally, we propose two new greedy heuristics to construct minimum energy broadcast trees. We show how our maximum critical energy algorithm may be coupled with our proposed greedy heuristics as well as with the greedy heuristics proposed earlier in the literature for the construction of minimum energy broadcast trees. Extensive simulations performed by us show that this coupling improves network lifetime significantly (between 48.3% and 328.9%) when compared with network lifetime using the base greedy heuristics in isolation.
Language modeling and encryption on packet switched networks

The holy grail of a mathematical model of secure encryption is to devise a model that is both faithful in its description of the real world, and yet admits a construction for an encryption system that fulfills a meaningful definition of security against a realistic adversary. While enormous progress has been made during the last 60 years toward this goal, existing models of security still overlook features that are closely related to the fundamental nature of communication. As a result there is substantial doubt in this author's mind as to whether there is any reasonable definition of “secure encryption” on the Internet.
Intrinsic ultracontractivity, conditional lifetimes and conditional gauge for symmetric stable processes on rough domains

For a symmetric $\alpha$-stable process $X$ on $\mathbf{R}^{n}$ with $0 \lt \alpha \lt 2$, $n \geq 2$ and a domain $D \subset \mathbf{R}^{n}$, let $L^{D}$ be the infinitesimal generator of the subprocess of $X$ killed upon leaving $D$. For a Kato class function $q$, it is shown that $L^{d}+q$ is intrinsic ultracontractive on a Holder domain $D$ of order 0. Then this is used to establish the conditional gauge theorem for $X$ on bounded Lipschitz domains in $\mathbf{R}^{n}$. It is also shown that the conditional lifetimes for symmetric stable process in a Holder domain of order 0 are uniformly bounded.
On Einstein Algebras and Relativistic Spacetimes

In this paper, we examine the relationship between general relativity and the theory of Einstein algebras. We show that according to a formal criterion for theoretical equivalence recently proposed by Halvorson (2012, 2015) and Weatherall (2015), the two are equivalent theories.
On quantum cohomology rings of partial flag varieties

0. Introduction. The main goal of this paper is to give a unified description for the structure of the small quantum cohomology rings for all projective homogeneous spaces SLn(C)/P , where P is a parabolic subgroup. The quantum cohomology ring of a smooth projective variety, or more generally of a symplectic manifoldX, has been introduced by string theorists (see [Va] and [W1]). Roughly speaking, it is a deformation of the usual cohomology ring, with parameter space given byH ∗(X). The multiplicative structure of quantum cohomology encodes the enumerative geometry of rational curves on X. In the past few years, the highly nontrivial task of giving a rigorous mathematical treatment of quantum cohomology has been accomplished both in the realm of algebraic and symplectic geometry. In various degrees of generality, this can be found in [Beh], [BehM], [KM], [LiT1], [LiT2], [McS], and [RT], as well as in the surveys [FP] and [T]. If one restricts the parameter space to H 1,1(X), one gets the small quantum cohomology ring. This ring, in the case of partial flag varieties, is the object of the present paper. In order to state our main results, we first describe briefly the “classical” side of the story. We interpret the homogeneous space F := SLn(C)/P as the complex, projective variety, parametrizing flags of quotients of C of given ranks, say, nk > · · ·> n1. By a classical result of Ehresmann [E], the integral cohomology of F can be described geometrically as the free abelian group generated by the Schubert classes. These are the (Poincare duals of) fundamental classes of certain subvarieties w ⊂ F , one for each element of the subset S := S(n1, . . . ,nk) of the symmetric group Sn, consisting of permutations w with descents in {n1, . . . ,nk}. A description of the multiplicative structure is provided by yet another classical theorem, due to Borel [Bor], which gives a presentation forH ∗(F,Z). Specifically, let σ 1 1 , . . . ,σ 1 n1 ,σ 2 1 , . . . ,σ 2 n2−n1, . . . ,σ k+1 1 , . . . ,σ k+1 n−nk be n independent variables. Define An to be the block-diagonal matrix diag(D1,D2, . . . ,Dk+1), where
Conjugacy Length in Group Extensions

Determining the length of short conjugators in a group can be considered as an effective version of the conjugacy problem. The conjugacy length function provides a measure for these lengths. We study the behavior of conjugacy length functions under group extensions, introducing the twisted and restricted conjugacy length functions. We apply these results to show that certain abelian-by-cyclic groups have linear conjugacy length function and certain semidirect products ℤd ⋊ ℤk have at most exponential (if k > 1) or linear (if k = 1) conjugacy length functions.
A database of world infrastructure stocks, 1950-95

The author describes an annual database of physical infrastructure stocks for a cross-section of 152 countries for 1950-95. The database contains six measures: kilometers of roads; kilometers of paved roads; kilometers of railway lines; number of telephones; number of telephone main lines; and KW of electricity generating capacity. The database includes some measures of infrastructure quality (percentage of roads in poor condition, percentage of local phone calls that are unsuccessful, percentage availability of diesel locomotives, and percentage of electricity lost from the system), but only for recent years. the author examines correlation patterns and reports regressions relating infrastructure stocks to country population, per capita GDP, land area, and the urbanization ration. The relationship between infrastructure and economic growth is examined in a preliminary way. The author reports that: nontransportation infrastructure stocks tend to increase one-for-one with population but increase more than proportionately with per capita GDP; geographic factors (area, urbanization ration) appear to affect the provision of nontransportation infrastructure in poor countries but not in rich countries; transportation infrastructure appears to increase less than proportionately with population, and increases with income only after a middle-income threshold has been reached; and geographic factors seem to influence the length of total roads and rail lines but not of paved roads. Panel unit root tests indicate that the log infrastructure stock per capita series are nonstationary and have a unit root. Cross-section growth regressions show our common worldwide estimated regression results for infrastructure stocks to be stable, long-run relationships. Preliminary regression results suggest that have a greater number of telephone main lines per capita has a positive effect on economic growth.
The diagnosis and management of non-alcoholic fatty liver disease: practice Guideline by the American Association for the Study of Liver Diseases, American College of Gastroenterology, and the American Gastroenterological Association

These recommendations are based on the following: (1) a formal review and analysis of the recently published world literature on the topic [Medline search up to June 2011]; (2) the American College of Physicians’ Manual for Assessing Health Practices and Designing Practice Guidelines; (3) guideline policies of the three societies approving this document; and (4) the experience of the authors and independent reviewers with regards to NAFLD. Intended for use by physicians and allied health professionals, these recommendations suggest preferred approaches to the diagnostic, therapeutic and preventive aspects of care. They are intended to be flexible and adjustable for individual patients. Specific recommendations are evidence-based wherever possible, and when such evidence is not available or inconsistent, recommendations are made based on the consensus opinion of the authors. To best characterize the evidence cited in support of the recommendations, the AASLD Practice Guidelines Committee has adopted the classification used by the Grading of Recommendation Assessment, Development, and Evaluation (GRADE) workgroup with minor modifications (Table 1). The strength of recommendations in the GRADE system is classified as strong (1) or weak (2). The quality of evidence supporting strong or weak recommendations is designated by one of three levels: high (A), moderate (B) or low-quality (C). This is a practice guideline for clinicians rather than a review article and interested readers can refer to several comprehensive reviews published recently.
Pricing American-style securities using simulation

Abstract We develop a simulation algorithm for estimating the prices of American-style securities, i.e., securities with opportunities for early exercise. Our algorithm provides both point estimates and error bounds for the true security price. It generates two estimates, one biased high and one biased low, both asymptotically unbiased and converging to the true price. Combining the two estimators yields a confidence interval for the true price. The proposed algorithm is especially attractive (compared with lattice and finite-difference methods) when there are multiple state variables and a small number of exercise opportunities. Preliminary computational evidence is given.
Predictors of role legitimacy and role adequacy of social workers working with substance-using clients.

Role adequacy (feeling knowledgeable about one's work) and role legitimacy (believing that one has the right to address certain client issues) have long been key theoretical constructs regarding explanations why various helping professionals are reluctant to address drug misuse problems with clients. This study examines these concepts in a sample of social workers and social work students. Using regression analysis, it was determined that the social workers who had more clients with drug problems, had taken a course in drug work and had support for their role were more likely to feel legitimate in their work with drug-using clients. Training in drug use identification and intervention, being male, having more clients with drug problems and role support predicted role adequacy. Having a Master's degree, work setting and job function were not related to role adequacy or role legitimacy. Implications for social work education are discussed.
Molecular scaffolds with remote directing groups for selective palladium-catalyzed C–H bond functionalizations

Palladium-catalyzed C–H bond functionalizations using novel directing groups are described. The chiral directing group enables reactivity with high levels of site-specificity, achieving chemoselective, regioselective, and diastereoselective oxidations. The directing groups also feature aminal components, which allow in situ transacetalization and offer the potential for catalytic turnover of the organic frameworks. An X-ray crystal structure of a cyclometallated complex also provides information about the nature of the directing group.
A short, enantiospecific synthesis of a protected seco acid precursor to (R,R)-(−)-pyrenophorin

Abstract Described herein is a four-step enantiospecific synthesis of a protected seco acid precursor of (R,R)-(−)-pyrenophorin in 23% yield from a chiral β-ketoester 3 , which can be prepared in one step from ethyl acetoacetate by a standard procedure.
Microfluidics in the “Open Space” for Performing Localized Chemistry on Biological Interfaces

Local interactions between (bio)chemicals and biological interfaces play an important role in fields ranging from surface patterning to cell toxicology. These interactions can be studied using microfluidic systems that operate in the "open space", that is, without the need for the sealed channels and chambers commonly used in microfluidics. This emerging class of techniques localizes chemical reactions on biological interfaces or specimens without imposing significant "constraints" on samples, such as encapsulation, pre-processing steps, or the need for scaffolds. They therefore provide new opportunities for handling, analyzing, and interacting with biological samples. The motivation for performing localized chemistry is discussed, as are the requirements imposed on localization techniques. Three classes of microfluidic systems operating in the open space, based on microelectrochemistry, multiphase transport, and hydrodynamic flow confinement of liquids are presented.
Partisan Cycles in Congressional Elections and the Macroeconomy

In the postwar United States the president's party has always done worse in the midterm congressional elections than in the previous congressional election. Republican administrations exhibit below-average, and Democratic administrations above-average, economic growth in the first half of each term, whereas in the latter halves the two see equal growth. Our rational expectations model is consistent with these two regularities. In presidential elections, voters choose between two polarized candidates. They then use midterm elections to counterbalance the president's policies by strengthening the opposition in Congress. Since presidents of different parties are associated with different policies, our model predicts a (spurious) correlation between the state of the economy and elections. Our predictions contrast with those of retrospective voting models, in which voters reward the incumbent if the economy is doing well before the election. Our model performs empirically at least as well as, and often better than, alternative models.
On the fluctuations in consumption and market returns in the presence of labor and human capital: An equilibrium analysis

Abstract We examine the effects of human capital on consumption, stock market, and other fluctuations in a general equilibrium continuous-time model. A representative consumer–worker–investor derives utility from consumption and leisure. A representative firm demands labor as the sole input to a stochastic production technology, driven by general (possibly nonmultiplicative) shocks. For Cobb–Douglas utility and multiplicative shocks, labor is nonstochastic, and consumption and stock market volatility are equated, as under no human capital. Deviations from this are analyzed. For logarithmic utility and ‘constant elasticity of substitution’ production technology, cases are identified where the presence of labor causes consumption to be smoother than the stock market.
Improvement in the Thermoelectric Figure of Merit by La/Ag Cosubstitution in PbTe

The thermoelectric properties of La-doped and Ag/La codoped PbTe were investigated in the temperature range of 300 to ∼720 K. All samples crystallize in the NaCl-type structure without noticeable secondary phase and exhibit narrow bandgaps of 0.26−0.30 eV, typical of PbTe. La doping (≤5 at %) in PbTe significantly enhances the room temperature electrical conductivity to >5000 S/cm, indicating that La is an efficient electron donor. Hall coefficient data confirm the significant increase in electron carrier concentration from ∼2 × 1018 cm−3 at 300 K for PbTe to ∼5.3 × 1019 cm−3 for Pb0.99La0.01Te, and ∼1.7 × 1020 cm−3 for Pb0.95La0.05Te. Ag doping in Pb0.99La0.01Te has an opposite effect on the electron carrier concentration (∼2.0 × 1019 cm−3 at 300 K for Ag0.05Pb0.99La0.01Te and ∼1.5 × 1019 cm−3 for Ag0.1Pb0.99La0.01Te), consistent with the role of Ag as electron acceptor. The temperature dependence of mobility is discussed in detail using the physics of electron scattering and possible scattering mechanis...
Direct Numerical Simulations of Type Ia Supernovae Flames. I. The Landau-Darrieus Instability

Planar flames are intrinsically unstable in open domains because of thermal expansion across the burning front, i.e., the Landau-Darrieus instability. This instability leads to wrinkling and growth of the flame surface and corresponding acceleration of the flame, until it is stabilized by cusp formation. We look at the Landau-Darrieus instability for C/O thermonuclear flames at conditions relevant to the late stages of a Type Ia supernova explosion. Two-dimensional direct numerical simulations of both single-mode and multimode perturbations using a low Mach number hydrodynamics code are presented. We show the effect of the instability on the flame speed as a function of both the density and domain size, demonstrate the existence of the small-scale cutoff to the growth of the instability, and look for the proposed breakdown of the nonlinear stabilization at low densities. The effects of curvature on the flame are quantified through measurements of the growth rate and computation of the corresponding Markstein number. While accelerations of a few percent are observed, they are too small to have any direct outcome on the supernova explosion.
THE SENSITIVITY OF FIRST-GENERATION EPOCH OF REIONIZATION OBSERVATORIES AND THEIR POTENTIAL FOR DIFFERENTIATING THEORETICAL POWER SPECTRA

Statistical observations of the epoch of reionization (EOR) power spectrum provide a rich data set for understanding the transition from the cosmic ‘‘dark ages’’ to the ionized universe we see today. EOR observations have become an active area of experimental cosmology, and three first-generation observatories—MWA, PAST, and LOFAR—are currently under development. In this paper we provide the first quantitative calculation of the threedimensional power spectrum sensitivity, incorporating thedesign parameters of a planned array. This calculation is then used to explore the constraints these first-generation observations can place on the EOR power spectrum. The results demonstrate the potential for upcoming power spectrum observations to constrain theories of structure formation and reionization. Subject headings: early universe — intergalactic medium — radio lines: general — techniques: interferometric Online material: color figure
Mode-Locking in Driven Disordered Systems as a Boundary-Value Problem

We study mode-locking in disordered media as a boundary-value problem. Focusing on the simplest class of mode-locking models that consists of a single driven overdamped degree-of-freedom, we develop an analytical method to obtain the shape of the Arnol’d tongues in the regime of low AC-driving amplitude or high AC-driving frequency. The method is exact for a scalloped pinning potential and easily adapted to other pinning potentials. It is complementary to the analysis based on the well-known Shapiro’s argument that holds in the perturbative regime of large driving amplitudes or low driving frequency where the effect of pinning is weak.
On blind identifiability of multipath channels using fractional sampling and second-order cyclostationary statistics

The problem of blind identifiability of digital communication multipath channels using fractionally spaced samples is considered. Fractionally sampled data are cyclostationary rather than stationary. The problem is cast into a mathematical framework of parameter estimation for a vector stationary process with single input (information sequence) and multiple outputs, by using a time-series representation of a cyclostationary process. A necessary and sufficient condition for channel identifiability from the correlation function of the vector stationary process is derived. This result provides an alternative but equivalent statement of an existing result. Using this result, it is shown that certain class of multipath channels cannot be identified from the second-order statistics irrespective of how the sampling rate is chosen. >
Blocked force investigation of a Terfenol-D transducer

ABSTRACT The output force-strain relationship typical of the performance of Terfenol-D transducers under varied operating conditions is examined to study transducer blocked force characteristics. The design and construction of a transducer for testing under controlled thermal, magnetic and mechanical load conditions are described. Results ofcompression tests at various applied magnetic fields and two initial mechanical stress states are used to generate loadlines and the blocked force characteristics ofthe transducer. Comparisons ofthe transducer's force and strain outputare made with published data. This test data is also used to examine the variability in Young's Modulus withapplied magnetic field, strain and stress.Keywords: blocked force, Terfenol-D, magnetostriction, transducer, load-line, Young's Modulus 1. INTRODUCTION Effective use of a transducer requires knowledge of its displacement and force outputs under a given input.Transducers utilizing the magnetostrictive alloy Terfenol-D are finding growing use, and a deeper grasp of theiroutput characteristics is needed to improve modeling and control. The following investigation of a Terfenol-Dtransducer is intended to shed some light on the response of Terfenol-D drivers under quasi-static conditions.Quasi-static changes in transducer displacement and force output for different applied magnetic field inputs will beexamined.As a starting point in the transducer analysis, consider the output characteristics of an ideal linear transducersketched in Figure 1. This represents a DC load line, where the transducer's ability to generate DC forces is linearlydependent on the displacement of the driving element. In particular, under no load (zero force produced) thetransducer's displacement is maximized, while as the strain produced tends toward zero the transducer's ability togenerate force is maximized. This maximum force may be termed as the "Blocked Force" rating ofthe transducer.Zero-DisplacementBlocked ForceMax-DisplacementNo-LoadDisplacement