cssi/SciSciGPT-SciSciNet huggingface dataset:
Long-Run Price Elasticity of Trade Flows and the Trade Comovement Puzzle

In this paper we argue that modeling dynamic properties of trade elasticity in a unified framework is essential for understanding one of the fundamental questions that lies at the intersection of business cycle and trade theory: What role do international trade linkages play in transmitting shocks across borders? Analytically, we show that in a broad class of open economy macroeconomic models shock transmission crucially depends on dynamic properties of trade elasticity. We demonstrate how modeling the dynamics of trade elasticity is thus of critical importance for applications aiming to relate economic models to cross-sectional variation of business cycle moments in the data. In the context of such applications, our paper cautions against drawing conclusions from models relaying on a single (static) trade elasticity and advocate the use of models consistent with dynamic elasticity.
Selective Hydrocarbon Oxidation in Zeolites

Zeolites are highly selective catalysts for partial oxidation of hydrocarbons, but practical applications require faster release of the products.
Foreign bank participation in developing countries : what do we know about the drivers and consequences of this phenomenon?

Foreign bank participation has increased steadily across developing countries since the mid-1990s. This paper documents this trend and surveys the existing literature to explore the drivers and consequences of this phenomenon, paying particular attention to the differences observed across regions both in the degree of foreign bank participation and in the impact of this process. Local profit opportunities, the absence of barriers to entry, and the presence of mechanisms to mitigate information problems have been the main factors driving foreign bank entry across developing countries. In general, foreign bank participation has been shown to exert a positive influence on banking sector efficiency and competition. The weight of the evidence suggests that foreign bank presence does not endanger, but rather enhances banking sector stability. And although some case studies suggest that foreign bank entry limits access to finance, many cross-country studies offer evidence to the contrary.
Pion electric polarizability from lattice QCD

Electromagnetic polarizabilities are important parameters for understanding the interaction between photons and hadrons. For pions these quantities are poorly constrained experimentally since they can only be measured indirectly. New experiments at CERN and Jefferson Lab are planned that will measure the polarizabilities more precisely. Lattice QCD can be used to compute these quantities directly in terms of quark and gluons degrees of freedom, using the background field method. We present results for the electric polarizability for two different quark masses, light enough to connect to chiral perturbation theory. These are currently the lightest quark masses used in polarizability studies.
The frozen-field approximation and the Ginzburg-Landau equations of superconductivity.

The Ginzburg-Landau (GL) equations of superconductivity provide a computational model for the study of magnetic flux vortices in type-II superconductors. In this article it is shown through numerical examples and rigorous mathematical analysis that the GL model reduces to the frozen-field model when the charge of the Cooper pairs (the superconducting charge carriers) goes to zero while the applied field stays near the upper critical field.
Passive Firm Learning and Employment Projection Error

This paper analyzes establishment error in estimating employment targets in business startups and expansions. Passive firm learning models provide a testable hypothesis that, other things being equal, old establishments more accurately predict future employment targets than young businesses. Empirical evidence from 442 Ohio establishments implies that an increase of ten years in establishment age is associated with a decrease in employment projection error rate of between 11 and 13 percentage points.
A new approach to building web-based interfaces for healthcare consumers

Healthcare websites, that are influential in healthcare decision-making, must be evaluated for accuracy, readability and understandability by the average population. Most existing frameworks for designing and evaluating interactive websites focus on the utility and usability of the site. Although these are significant to the design of the basic site, they are not sufficient. We have developed an iterative framework that considers these attributes longitudinally as information and structural formats change over time. The result will be websites high in ‘consumer usability’.
Field Theory Correlators and String Theory

It appears that string-M-theory is the only viable candidate for a complete theory of matter. It must therefore contain both gravity and QCD. What is particularly surprising is the recent conjecture that strongly coupled QCD matrix elements can be evaluated though a duality with weakly coupled gravity. To date there has been no direct verification of this conjecture by Maldacena because of the difficulty of direct strong coupling calculations in gauge theories. We report here on some progress in evaluating a gauge-invariant correlator in the non-perturbative regime in two and three dimensions in SYM theories. The calculations are made using supersymmetric discrete light-cone quantization (SDLCQ). We consider a Maldacena-type conjecture applied to the near horizon geometry of a D1-brane in the supergravity approximation, solve the corresponding N = (8,8) SYM theory in two dimensions, and evaluate the correlator of the stress-energy tensor. Our numerical results support the Maldacena conjecture and are within 10–15% of the predicted results. We also present a calculation of the stress-energy correlator in N = 1 SYM theory in 2+1 dimensions. While there is no known duality relating this theory to supergravity, the theory does have massless BPS states, and the correlator gives important information about the BPS wave function in the non-perturbative regime.
The (q,t)-Gaussian process

Abstract The ( q , t ) -Fock space F q , t ( H ) , introduced in this paper, is a deformation of the q -Fock space of Bozejko and Speicher. The corresponding creation and annihilation operators now satisfy the commutation relation a q , t ( f ) a q , t ( g ) ⁎ − q a q , t ( g ) ⁎ a q , t ( f ) = 〈 f , g 〉 H t N , a defining relation of the Chakrabarti–Jagannathan deformed quantum oscillator algebra. The moments of the deformed Gaussian element s q , t ( h ) : = a q , t ( h ) + a q , t ( h ) ⁎ are encoded by the joint statistics of crossings and nestings in pair partitions. The q = 0 t specialization yields a natural single-parameter deformation of the full Boltzmann Fock space of free probability, with the corresponding semicircular measure variously encoded via the Rogers–Ramanujan continued fraction, the t -Airy function, the t -Catalan numbers of Carlitz–Riordan, and the first-order statistics of the reduced Wigner process.
Wages and International Trade

In this Paper, I present direct micro-econometric evidence of the relation between individual wages of French workers and the import behaviour of their employing firms. First, a model shows that the impact of firms’ imports on workers’ wages not only comes from movements in the quasi-rent induced by competitive pressures but also from alterations of workers and firms threat points in the bargaining process induced by trade. To estimate this model, I use a unique matched employer-employee data source that contains information on firms’ inputs, including imports by type of product and by country of origin, as well as individual characteristics of a representative sample of workers employed at those firms. Because the quasi-rent - a firm-level variable - and seniority - a person-level variable directly affected by import competition are endogenous in the wage equation, I use export prices of US firms to various destinations as instruments. To summarize my results, I find a bargaining power below 0.20. I also show that workers’ wages deteriorate through competitive pressures. Two effects are at play. In industries where firms actively import finished goods, workers’ wage is decreased. But, firms own imports of the same goods ‘protect’ its workers through a hold-up effect. The total effect is negative for most workers. Highly educated workers appear to benefit from trade, in stark contrast with less educated workers. Also, very experienced workers, when still employed in manufacturing firms, appear to benefit from the hold-up effect but to be most affected by the firm’s competitor’s imports.
State space for planar Majorana zero modes

Zero modes arising from a planar Majorana equation in the presence of $N$ vortices require an $\mathcal{N}$-dimensional state space, where $\mathcal{N}={2}^{N/2}$ for $N$ even and $\mathcal{N}={2}^{(N+1)/2}$ for $N$ odd. The mode operators form a restricted $\mathcal{N}$-dimensional Clifford algebra.
Succinct malleable NIZKs and an application to compact shuffles

Depending on the application, malleability in cryptography can be viewed as either a flaw or — especially if sufficiently understood and restricted — a feature. In this vein, Chase, Kohlweiss, Lysyanskaya, and Meiklejohn recently defined malleable zero-knowledge proofs, and showed how to control the set of allowable transformations on proofs. As an application, they construct the first compact verifiable shuffle, in which one such controlled-malleable proof suffices to prove the correctness of an entire multi-step shuffle. Despite these initial steps, a number of natural problems remained: (1) their construction of controlled-malleable proofs relies on the inherent malleability of Groth-Sahai proofs and is thus not based on generic primitives; (2) the classes of allowable transformations they can support are somewhat restrictive. In this paper, we address these issues by providing a generic construction of controlled-malleable proofs using succinct non-interactive arguments of knowledge, or SNARGs for short. Our construction can support very general classes of transformations, as we no longer rely on the transformations that Groth-Sahai proofs can support.
Stochastically consistent caching and dynamic duty cycling for erratic sensor sources

We present a novel dynamic duty cycling scheme to maintain stochastic consistency for caches in sensor networks. To reduce transmissions, base stations often maintain caches for erratically changing sensor sources. Stochastic consistency guarantees the cache-source deviation is within a pre-specified bound with a certain confidence level. We model the erratic sources as Brownian motions, and adaptively predict the next cache update time based on the model. By piggybacking the next update time in each regular data packet, we can dynamically adjust the relaying nodes' duty cycles so that they are awake before the next update message arrives, and are sleeping otherwise. Through simulations, we show that our approach can achieve very high source-cache fidelity with low power consumption on many real-life sensor data. On average, our approach consumes 4-5 times less power than GAF [1], and achieves 50% longer network lifetime.
Inapproximability After Uniqueness Phase Transition in Two-Spin Systems

A two-state spin system is specified by a matrix A = [ A0,0 A0,1 A1,0 A1,1 ] = [ β 1 1 γ ] where β, γ ≥ 0. Given an input graph G = (V,E), the partition function ZA(G) of a system is defined as ZA(G) = ∑
Onion-shell model of cosmic ray acceleration in supernova remnants

A method is devised to approximate the spatially averaged momentum distribution function for the accelerated particles at the end of the active lifetime of a supernova remnant. The analysis is confined to the test particle approximation and adiabatic losses are oversimplified, but unsteady shock motion, evolving shock strength, and non-uniform gas flow effects on the accelerated particle spectrum are included. Monoenergetic protons are injected at the shock front. It is found that the dominant effect on the resultant accelerated particle spectrum is a changing spectral index with shock strength. High energy particles are produced in early phases, and the resultant distribution function is a slowly varying power law over several orders of magnitude, independent of the specific details of the supernova remnant.
Aerodynamic Characteristics of a Hypersonic Viscous Optimized Waverider at High Altitudes

The present paper addresses the applicability of the basic concept of waveriding at high altitudes, and the extent to which the large viscous forces degrade the aerodynamic performance of waveriders. The waverider under consideration was designed using a continuum flow methodology. It is shown that the lift-to-drag ratio of high-altitude/high-Knudsen-number waveriders can be expected to be significantly lower than their low altitude/low Knudsen number counterparts. The aerodynamic performance of a representative waverider which was optimized for a 90-km, Mach-25 application is studied for altitudes ranging from 97 km to 145 km and incidence angles of 0 to 30 deg. Typical values of the lift-to-drag ratio were computed to be in the range of 0 to 0.3. Friction forces are mostly responsible for this poor performance. Friction forces account for more than 93 percent of the drag and significantly reduce lift.
An integrated active power filter-ultracapacitor design to provide intermittency smoothing and reactive power support to the distribution grid

Grid integration of distributed energy resources (DERs) is increasing rapidly. Furthermore, smart grid technologies are making the grid more bi-directional providing opportunities to consumers to supply power back to the grid. Energy storage technologies like battery and ultracapacitor (UCAP) can be integrated through grid tied-inverters to support variable DERs such as solar and wind. In these cases, the energy storage with active power capability can improve grid performance by providing active and reactive power support. In this paper, the concept of providing active/reactive power support and renewable intermittency smoothing to the distribution grid by UCAPs is presented. UCAPs have higher number of charge-discharge cycles and higher terminal voltage per module when compared to batteries which make them ideal for providing grid support. The UCAP is integrated into the dc-link of the active power filter (APF) through a dc-dc converter. The dc-dc converter provides a stiff dc-link voltage which improves the performance of the grid tied-inverter. Design and control of both the dc-ac inverter and the dc-dc converter are very important in this regard and presented. The simulation model of the overall system is developed and results are compared to the results from experimental hardware setup.
Degree Scale Anisotropy: Current Status

The Cosmic Background Radiation gives us one of the few probes into the density perturbations in the early universe that should later lead to the formation of structure we now observe. Recent advances in degree scale anisotropy measurements have allowed us to begin critically testing cosmological models. Combined with the larger scale measurements from COBE we are now able to directly compare data and theory. These measurements promise future progress in understanding structure formation. Because of the extreme sensitivities needed (1–10 ppm) and the difficulties of foreground sources, these measurements require not only technological advances in detector and measurement techniques, but multi spectral measurements and careful attention to low level systematic errors. This field is advancing rapidly and is in a true discovery mode. Our own group has been involved in a series of eleven experiments over the last six years using the ACME (Advanced Cosmic Microwave Explorer) payload which has made measurements at angular scales from 0.3 to 3 degrees and over a wavelength range from 1 to 10 mm. The recent data from these and other measurements will be reviewed as well as some of the challenges and potential involved in these and future measurements.
Predictive quantile regression with persistent covariates: IVX-QR approach

This paper develops econometric methods for inference and prediction in quantile regression (QR) allowing for persistent predictors. Conventional QR econometric techniques lose their validity when predictors are highly persistent. I adopt and extend a methodology called IVX filtering (Magdalinos and Phillips, 2009) that is designed to handle predictor variables with various degrees of persistence. The proposed IVX-QR methods correct the distortion arising from persistent multivariate predictors while preserving discriminatory power. Simulations confirm that IVX-QR methods inherit the robust properties of QR. These methods are employed to examine the predictability of US stock returns at various quantile levels.
The reinforcing properties of ethanol are quantitatively enhanced in adulthood by peri-adolescent ethanol, but not saccharin, consumption in female alcohol-preferring (P) rats

Alcohol drinking during adolescence is associated in adulthood with heavier alcohol drinking and an increased rate of alcohol dependence. Past research in our laboratory has indicated that peri-adolescent ethanol consumption can enhance the acquisition and reduce the rate of extinction of ethanol self-administration in adulthood. Caveats of the past research include reinforcer specificity, increased oral consumption during peri-adolescence, and a lack of quantitative assessment of the reinforcing properties of ethanol. The current experiments were designed to determine the effects of peri-adolescent ethanol or saccharin drinking on acquisition and extinction of oral ethanol self-administration and ethanol seeking, and to quantitatively assess the reinforcing properties of ethanol (progressive ratio). Ethanol or saccharin access by alcohol-preferring (P) rats occurred during postnatal day (PND) 30–60. Animals began operant self-administration of ethanol or saccharin after PND 85. After 10 weeks of daily operant self-administration, rats were tested in a progressive ratio paradigm. Two weeks later, self-administration was extinguished in all rats. Peri-adolescent ethanol consumption specifically enhanced the acquisition of ethanol self-administration, reduced the rate of extinction for ethanol self-administration, and quantitatively increased the reinforcing properties of ethanol during adulthood. Peri-adolescent saccharin consumption was without effect. The data indicate that ethanol consumption during peri-adolescence results in neuroadaptations that may specifically enhance the reinforcing properties of ethanol during adulthood. This increase in the reinforcing properties of ethanol could be a part of biological sequelae that are the basis for the effects of adolescent alcohol consumption on the increase in the rate of alcoholism during adulthood.
Some problems for convex Bayesians

We discuss problems for convex Bayesian decision making and uncertainty representation. These include the inability to accommodate various natural and useful constraints and the possibility of an analog of the classical Dutch Book being made against an agent behaving in accordance with convex Bayesian prescriptions. A more general set-based Bayesianism may be as tractable and would avoid the difficulties we raise.
Compressed parameterized pattern matching

Pattern matching between traditional strings is well-defined for both uncompressed and compressed sequences. Prior to this work, parameterized pattern matching (p-matching) was defined predominately by the matching between uncompressed parameterized strings (p-strings) from the constant alphabet Σ and the parameter alphabet ?. In this work, we define the compressed parameterized pattern matching (compressed p-matching) problem to find all of the p-matches between a pattern P and text T, using only P and the compressed text T c . Initially, we present parameterized compression (p-compression) as a new way to losslessly compress data. Experimentally, we show that p-compression is competitive with various other standard compression schemes. Subsequently, we provide the compression and decompression algorithms. Next, two different approaches are developed to address the compressed p-matching problem: (1) using the recently proposed parameterized arithmetic codes (pAC) and (2) using the parameterized border array (p-border). Our general solution is independent of the underlying compression scheme. The results are further examined for catenate, Tunstall codes, Huffman codes, and LZSS.
Optimization of Constructive Solid Geometry Via a Tree-Based Multi-objective Genetic Algorithm

This paper presents the multi-objective evolutionary optimization of three-dimensional geometry represented via constructive solid geometry (CSG), a binary tree of boolean operations of solid primitives. NSGA-II is ex- tended for binary tree chromosomes with customized crossover and mutation operators tailored for the evolution of CSG trees and applied for two-objective shape optimization of indoor modular space truss joints. The results show suc- cess in generating a variety of shapes over the Pareto front. A selection of Pa- reto-optimal shapes are manufactured using a solid freeform fabrication proc- ess.
Stability versus maneuverability in hovering flight

Insects and birds are often faced by opposing requirements for agile and stable flight. Here, we explore the interplay between aerodynamic effort, maneuverability, and stability in a model system that consists of a Λ-shaped flyer hovering in a vertically oscillating airflow. We determine effective conditions that lead to periodic hovering in terms of two parameters: the flyer’s shape (opening angle) and the effort (flow acceleration) needed to keep the flyer aloft. We find optimal shapes that minimize effort. We then examine hovering stability and observe a transition from unstable, yet maneuverable, to stable hovering. Interestingly, this transition occurs at post-optimal shapes, that is, at increased aerodynamic effort. These results have profound implications on the interplay between stability and maneuverability in live organisms as well as on the design of man-made air vehicles.
Starcounts Redivivus. III. A Possible Detection of the Sagittarius Dwarf Spheroidal Galaxy at b = −40°

As part of the Selected Areas Starcounts Survey, a CCD survey to V > 21, we have obtained VI photometry of two fields at b = ?40? aligned roughly with an extrapolation of the major axis of the Sagittarius dwarf spheroidal galaxy. Comparison of the color-magnitude diagram (CMD) for some of these fields with the CMDs of fields reflected about the Galactic l = 0? meridian reveals an excess of stars at V0 = 17.85 and 0.9 < (V-I)0 < 1.1 in the (l, b) = (11?, -40?) field. The excess stars have colors consistent with the Sgr red clump, and deeper CMD imaging in these locations shows evidence of a main-sequence turnoff (MSTO) at V = 21, with the main sequence extending to the limit of our data (V = 24). The surface brightnesses we derive from either the potential excess of red clump stars or the apparent excess of MSTO stars are consistent with each other and with the results of other surveys at this latitude. No similar excess appears in our northern Galactic hemisphere fields near the (l, b) = (353?, +41?) field. We have obtained spectroscopy of all 30 candidate red clump stars in the range 0.9 < (V-I)0 < 1.1and 17.75 < V0 < 17.95. The radial velocity distribution of the stars, while dissimilar from expectations of Galactic structure models, does not show a contribution by stars near the Galactocentric radial velocity seen in other studies near the Sgr core. It is difficult to reconcile a photometric result that is consistent with other explorations of the Sagittarius stream with a radial velocity distribution that is apparently inconsistent. In a companion paper, we discuss how some of the discrepancies are resolved if our potential Sgr detection corresponds to a different Sgr tidal streamer than that detected by most other surveys.
High Temperature Expansion for a Driven Bilayer System

Based directly on the microscopic lattice dynamics, a simple high temperature expansion can be devised for non-equilibrium steady states. We apply this technique to investigate the disordered phase and the phase diagram for a driven bilayer lattice gas at half filling. Our approximation captures the phases first observed in simulations, provides estimates for the transition lines, and allows us to compute signature observables of non-equilibrium dynamics, namely, particle and energy currents. Its focus on non-universal quantities offers a useful analytic complement to field-theoretic approaches.
Repression and punishment in North Korea : survey evidence of prison camp experiences

The penal system has played a central role in the North Korean government’s response to the country’s profound economic and social changes. Two refugee surveys—one conducted in China, one in South Korea—document its changing role. The regime disproportionately targets politically suspect individuals, particularly those involved in market-oriented economic activities. Levels of violence and deprivation do not appear to differ substantially between the infamous political prison camps, penitentiaries for felons, and labor camps used to incarcerate individuals for misdemeanors, including economic crimes. Substantial numbers of those incarcerated report experiencing deprivation with respect to food as well as public executions and other forms of violence. This repression appears to work; despite substantial cynicism about the North Korean system, refugees do not report signs of collective action aimed at confronting the regime. Such a system may also reflect ulterior motives. High levels of discretion with respect to arrest and sentencing and very high costs of detention, arrest and incarceration encourage bribery; the more arbitrary and painful the experience with the penal system, the easier it is for officials to extort money for avoiding it. These characteristics not only promote regime maintenance through intimidation, but may facilitate predatory corruption as well.
Identification and Estimation of Auctions with Incomplete Contracts: A Structural Analysis of California Highway Construction Projects

We introduce a structural model of procurement auctions with incomplete contracts, where a procurer chooses an initial project specification endogenously. The contract between the procurer and the winner of the auction is incomplete in that the two parties may agree to adopt a new feasible specification later, and negotiate an additional transfer via Nash Bargaining where both parties’ disagreement values depend on the auction price. In a Perfect Bayesian Equilibrium, contractors competing in the auction take account of such incompleteness while quoting prices. We show that the model primitives are non-parametrically identified and propose a feasible estimation procedure. Using data from highway procurement auctions in California, we estimate the structural elements that determine the hold-up due to incompleteness, and infer how a contractor’s bargaining power and the mark-up in the price quoted vary with its characteristics and the features of the construction project. We also find that ignoring the existence of contract incompleteness in the structural analysis of the bidding data leads to substantial over-estimation of the mark-ups in the prices.
The Effects of Asymmetric and Symmetric Fetal Growth Restriction on Human Capital Development

This paper explores the causal pathway by which poor fetal health translates into reducing educational attainment and earnings as an adult. Using insights from the medical literature, I decompose low birth weight infants into two distinct subtypes: a symmetric type, which is characterized by cognitive deficits, and an asymmetric type, which exhibits little to no cognitive problems. Using data from a longitudinal survey of newborns, I establish three results: First, there is empirical evidence of brain sparing in the asymmetric subtype, but not in the symmetric subtype. Second, despite differences in cognitive impairment, both subtypes exhibit similar impairment to physical health. And finally, there is evidence that the causes and timing of onset during pregnancy are different for asymmetric and symmetric growth restriction. The results indicate that differentiating between these subtypes may offer new opportunities to identify the underlying casual relationships between health and human capital development, as well as uncovering the "black box" mechanism behind the fetal origins hypothesis. These results also have broad implications for the timing of policy interventions aimed at pregnant women.
External-memory network analysis algorithms for naturally sparse graphs

In this paper, we present a number of network-analysis algorithms in the external-memory model. We focus on methods for large naturally sparse graphs, that is, n-vertex graphs that have O(n) edges and are structured so that this sparsity property holds for any subgraph of such a graph. We give efficient external-memory algorithms for the following problems for such graphs: 1. Finding an approximate d-degeneracy ordering. 2. Finding a cycle of length exactly c. 3. Enumerating all maximal cliques. Such problems are of interest, for example, in the analysis of social networks, where they are used to study network cohesion.
Action Recognition by Hierarchical Mid-Level Action Elements

Realistic videos of human actions exhibit rich spatiotemporal structures at multiple levels of granularity: an action can always be decomposed into multiple finer-grained elements in both space and time. To capture this intuition, we propose to represent videos by a hierarchy of mid-level action elements (MAEs), where each MAE corresponds to an action-related spatiotemporal segment in the video. We introduce an unsupervised method to generate this representation from videos. Our method is capable of distinguishing action-related segments from background segments and representing actions at multiple spatiotemporal resolutions. Given a set of spatiotemporal segments generated from the training data, we introduce a discriminative clustering algorithm that automatically discovers MAEs at multiple levels of granularity. We develop structured models that capture a rich set of spatial, temporal and hierarchical relations among the segments, where the action label and multiple levels of MAE labels are jointly inferred. The proposed model achieves state-of-the-art performance in multiple action recognition benchmarks. Moreover, we demonstrate the effectiveness of our model in real-world applications such as action recognition in large-scale untrimmed videos and action parsing.
Canonical Quantum Gravity with New Variables and Loops: A Report

This is a brief and updated summary of a talk given at the International Conference on Gravitation and Cosmology that took place in Poona in December 1995. It is very brief and is mostly intended as a guide to current literature, or to keep people updated only in very broad terms on the latest developments in the subject.
Economic implications of moving toward global convergence on emission intensities

One key contentious issue in climate change negotiations is the huge difference in carbon dioxide (CO2) emissions per capita between more advanced industrialized countries and other nations. This paper analyzes the costs of reducing this gap. Simulations using a global computable general equilibrium model show that the average the carbon dioxide intensity of advanced industrialized countries would remain almost twice as high as the average for other countries in 2030, even if the former group adopted a heavy uniform carbon tax of $250/tCO2 that reduced their emissions by 57 percent from the baseline. Global emissions would fall only 18 percent, due to an increase in emissions in the other countries. This reduction may not be adequate to move toward 2050 emission levels that avoid dangerous climate change. The tax would reduce Annex I countries' gross domestic product by 2.4 percent, and global trade volume by 2 percent. The economic costs of the tax vary significantly across countries, with heavier burdens on fossil fuel intensive economies such as Russia, Australia, the United Kingdom and the United States.
Incompressible surfaces in link complements

We generalize a theorem of Finkelstein and Moriah and show that if a link L has a 2n-plat projection satisfying certain conditions, then its cornplement contains some closed essential surfaces. In most cases these surfaces remain essential after any totally nontrivial surgery on L. A link L in S3 has a 2n-plat projection for some n, as shown in Figure 1, where a box on the i-th row and j-th column consists of 2 vertical strings with an aij left-hand half twist; in other words, it is a rational tangle of slope 1/aij. See for example [BZ]. Let n be the number of boxes in the even rows, so there are n 1 boxes in the odd rows. Let m be the number of rows in the diagram. It was shown by Finkelstein and Moriah [FMi], [FM2] that if n > 3, m > 5, and if laijI > 3 for all i, j, then the link exterior E(L) = S3 IntN(L) contains some essential planar surfaces, which can be tubed on one side to obtain closed incompressible surfaces in E(K). In this note we will prove a stronger version of this theorem, showing that E(L) contains some essential surfaces if n > 3, the boxes at the two ends of the odd rows have IaijI > 3, and aij 0 for the boxes which are not on the ends of the rows. We allow aij = 0 for boxes at the ends of the even rows, and there is no restriction on m, the number of rows in the diagram. The argument here provides a much simpler proof to the above theorem of Finkelstein and Moriah. In [FM2] that theorem was applied to show that if L is a knot, then all surgeries on L contain essential surfaces. Corollary 2 below generalizes this to the case when L has multiple components, with a mild restriction that each component of L intersects some "allowable" spheres. We first give some definitions. Let a = a(al,... , am) be an arc running monotonically from the top to the bottom of the 2n-plat, such that ae. is disjoint from the boxes, and on the i-th row there are ai boxes on the left of oa. See Figure 1 for the arc ai(1, 1, 1, 2, 2). The arc ae is an allowable path if (i) each row has at least one box on each side of oa, and (ii) ae intersects L at m + 1 points (so ae intersects L once when passing from one row to another). Note that the leftmost allowable path is a(1,... , 1), which has on its left one box from each row. Given an allowable path a = a(ai,... , am), we can connect the two ends of ae by an arc 13 disjoint from the projection of L to form a circle, then cap it off by two disks, one on each side of the projection plane, to get a sphere S = S(ai,... , am), Received by the editors February 22, 2000 and, in revised form, March 27, 2000. 1991 Mathematics Subject Classification. Primary 57N10, 57M25.
Similar Efficacies of Selection Shape Mitochondrial and Nuclear Genes in Both Drosophila melanogaster and Homo sapiens

Deleterious mutations contribute to polymorphism even when selection effectively prevents their fixation. The efficacy of selection in removing deleterious mitochondrial mutations from populations depends on the effective population size (Ne) of the mitochondrial DNA and the degree to which a lack of recombination magnifies the effects of linked selection. Using complete mitochondrial genomes from Drosophila melanogaster and nuclear data available from the same samples, we reexamine the hypothesis that nonrecombining animal mitochondrial DNA harbor an excess of deleterious polymorphisms relative to the nuclear genome. We find no evidence of recombination in the mitochondrial genome, and the much-reduced level of mitochondrial synonymous polymorphism relative to nuclear genes is consistent with a reduction in Ne. Nevertheless, we find that the neutrality index, a measure of the excess of nonsynonymous polymorphism relative to the neutral expectation, is only weakly significantly different between mitochondrial and nuclear loci. This difference is likely the result of the larger proportion of beneficial mutations in X-linked relative to autosomal loci, and we find little to no difference between mitochondrial and autosomal neutrality indices. Reanalysis of published data from Homo sapiens reveals a similar lack of a difference between the two genomes, although previous studies have suggested a strong difference in both species. Thus, despite a smaller Ne, mitochondrial loci of both flies and humans appear to experience similar efficacies of purifying selection as do loci in the recombining nuclear genome.
In Situ Formation of an Oxygen-Evolving Catalyst in Neutral Water Containing Phosphate and Co2+

The utilization of solar energy on a large scale requires its storage. In natural photosynthesis, energy from sunlight is used to rearrange the bonds of water to oxygen and hydrogen equivalents. The realization of artificial systems that perform "water splitting" requires catalysts that produce oxygen from water without the need for excessive driving potentials. Here we report such a catalyst that forms upon the oxidative polarization of an inert indium tin oxide electrode in phosphate-buffered water containing cobalt (II) ions. A variety of analytical techniques indicates the presence of phosphate in an approximate 1:2 ratio with cobalt in this material. The pH dependence of the catalytic activity also implicates the hydrogen phosphate ion as the proton acceptor in the oxygen-producing reaction. This catalyst not only forms in situ from earth-abundant materials but also operates in neutral water under ambient conditions.
Room-temperature enantioselective C–H iodination via kinetic resolution

Asymmetric carbon-hydrogen (C-H) activation reactions often rely on desymmetrization of prochiral C-H bonds on the same achiral molecule, using a chiral catalyst. Here, we report a kinetic resolution via palladium-catalyzed enantioselective C-H iodination in which one of the enantiomers of a racemic benzylic amine substrates undergoes faster aryl C-H insertion with the chiral catalysts than the other. The resulting enantioenriched C-H functionalization products would not be accessible through desymmetrization of prochiral C-H bonds. The exceedingly high relative rate ratio (k(fast)/k(slow) up to 244), coupled with the subsequent iodination of the remaining enantiomerically enriched starting material using a chiral ligand with the opposite configuration, enables conversion of both substrate enantiomers into enantiomerically pure iodinated products.
Designing Computer Circuits with a Computer

The circuit to be considered is that of a transistor flipflop as shown in Figure 1. All polarities are chosen for NPN transistors. In this analysis, the transistor re, rb, and rc, will be assumed neglibible for simplicity. It will also be assumed that (equation) where α is the current gain of the transistor.
Aortic dissection: the tear that kills.

This deadly cardiac condition requires rapid identification and immediate medical intervention.
Saturn's rings: 3-mm low-inclination observations and derived properties

To determine a more precise brightness temperature and more accurate properties for Saturn's rings, 3.3 mm low inclination observations have been made at 90 GHz with the Aerospace 4.6 m radio telescope. A mean brightness temperature of 17 plus or minus 4 K has been determined by comparing the data with the variation of the inclination of the total flux from the planet and rings predicted by a simple model with uniformly bright A and B rings. Variation of the normal optical depth from 0.4 to 1.0 resulted in a total variation of about 1.5 K in A and B brightness. A portion of the brightness attributed to ring particle thermal emission has been determined to be at a temperature of 11 plus or minus 5 K. If the maximum particle radius (approximately 5 m) deduced from Voyager bistatic radar observations is correct, results indicate a particle distribution ranging between 1 cm and several meters radius of the form r exp -s with s = 3.3-3.6, or a material absorption coefficient ranging between 3 and 10 times lower than that of pure water ice at 85 K, or both. An increase in the porosity of the ice particles through a decrease in their density will not produce the observed particle albedo. If the rocky material is uniformly distributed, low ring brightness temperature would allow a silicate upper limit of approximately 10 percent by mass; however, the silicate material could be more abundant if it is separated from the icy material.
THE VECTOR VORTEX CORONAGRAPH: LABORATORY RESULTS AND FIRST LIGHT AT PALOMAR OBSERVATORY

High-contrast coronagraphy will be needed to image and characterize faint extrasolar planetary systems. Coronagraphy is a rapidly evolving field, and many enhanced alternatives to the classical Lyot coronagraph have been proposed in the past 10 years. Here, we discuss the operation of the vector vortex coronagraph, which is one of the most efficient possible coronagraphs. We first present recent laboratory results and then first light observations at the Palomar observatory. Our near-infrared H-band (centered at ~1.65 μm) and K-band (centered at ~2.2 μm) vector vortex devices demonstrated excellent contrast results in the lab, down to ~10^(–6) at an angular separation of ~3λ/d. On sky, we detected a brown dwarf companion 3000 times fainter than its host star (HR 7672) in the K_s band (centered at ~2.15 μm), at an angular separation of ~2.5λ/d. Current and next-generation high-contrast instruments can directly benefit from the demonstrated capabilities of such a vector vortex: simplicity, small inner working angle, high optical throughput (>90%), and maximal off-axis discovery space.
Symmetric functions, parabolic category O, and the Springer fiber

We prove that the center of a regular block of parabolic category O for the general linear Lie algebra is isomorphic to the cohomology algebra of a corresponding Springer fiber. This was conjectured by Khovanov [K]. We also find presentations for the centers of singular blocks, which are cohomology algebras of Spaltenstein varieties
CMBFAST for Spatially Closed Universes

We extend the cosmological linear perturbation theory code CMBFAST to closed geometries. This completes the implementation of CMBFAST to all types of geometries and allows the user to perform an unlimited search in the parameter space of models. This will be especially useful for placing confidence limits on cosmological parameters from existing and future data. We discuss some of the technical issues regarding the implementation.
Metallization of fluid hydrogen

The electrical resistivity of liquid hydrogen has been measured at the high dynamic pressures, densities and temperatures that can be achieved with a reverberating shock wave. The resulting data are most naturally interpreted in terms of a continuous transition from a semiconducting to a metallic largely diatomic fluid, the latter at 140 GPa (nine–fold compression) and 3000 K. While the fluid at these conditions resembles common liquid metals by the scale of its resistivity of 500 μΩ cm, it differs by retaining a strong pairing character, and the precise mechanism by which a metallic state might be attained is still a matter of debate. Some evident possibilities include: (i) physics of a largely one–body character, such as a band–overlap transition; (ii) physics of a strong–coupling or many–body character, such as a Mott–Hubbard transition; and (iii) processes in which structural changes are paramount.
Dolbeault cohomology of a loop space

The loop space LP_1 of the Riemann sphere is an infinite dimensional complex manifold consisting of maps (loops) from S^1 to P_1 in some fixed C^k or Sobolev W^{k,p} space. In this paper we compute the Dolbeault cohomology groups H^{0,1}(LP_1).
A Neyman–Pearson Approach to Universal Erasure and List Decoding

When information is to be transmitted over an unknown, possibly unreliable channel, an erasure option at the decoder is desirable. Using constant-composition random codes, we propose a generalization of Csiszar and Korner's maximum mutual information (MMI) decoder with an erasure option for discrete memoryless channels. The new decoder is parameterized by a weighting function that is designed to optimize the fundamental tradeoff between undetected-error and erasure exponents for a compound class of channels. The class of weighting functions may be further enlarged to optimize a similar tradeoff for list decodersin that case, undetected-error probability is replaced with average number of incorrect messages in the list. Explicit solutions are identified. The optimal exponents admit simple expressions in terms of the sphere-packing exponent, at all rates below capacity. For small erasure exponents, these expressions coincide with those derived by Forney (1968) for symmetric channels, using maximum a posteriori decoding. Thus, for those channels at least, ignorance of the channel law is inconsequential. Conditions for optimality of the Csiszar-Korner rule and of the simpler empirical-mutual-information thresholding rule are identified. The error exponents are evaluated numerically for the binary symmetric channel.
Imaging of Interstitial Lung Disease

The pulmonary interstitium is affected by a broad group of diseases. Of roughly 150 diseases, only a small subset is encountered regularly. Idiopathic interstitial pneumonias, sarcoidosis, Langerhans cell histiocytosis (LCH), hypersensitivity pneumonitis, and pneumoconiosis are among the most common. The consensus statement on interstitial pneumonias further classifies interstitial lung diseases into idiopathic interstitial pneumonias, diffuse parenchymal lung disease from known causes (eg, collagen vascular diseases), granulomatous disease (sarcoidosis), and a miscellaneous group that includes lymphangioleiomyomatosis (LAM) and LCH [1]. This article presents the imaging findings in sarcoidosis, silicosis, asbestosis, LAM, LCH, collagen vascular diseases, hypersensitivity pneumonitis, and pulmonary alveolar proteinosis (PAP) (Table 1). The idiopathic interstitial pneumonias are discussed in the second article on imaging of interstitial lung disease.
Optimal Design of Anisotropic (Fiber-Reinforced) Flywheels

An analysis is given of the kinetic energy storage capacity of anisotropic flywheels. Using a uniform strain failure criteria, the optimal shapes of flywheels are determined as a function of the degree of anisotropy. Within this spectrum of shapes, practical design considerations are shown to favor the case where there is equal reinforcement in the radial and circumferential directions. Comparisons are made between the present solid-wheel-type design and the ring design and also between candidate materials.
Glueballs and the universal energy spectrum of tight knots and links

Systems of tightly knotted, linked, or braided flux tubes will have a universal mass-energy spectrum if the flux is quantized. We focus on a model of glueballs as knotted QCD flux tubes.
The Chilling Effect of Optimism: The Case of Final-Offer Arbitration

This article examines the incentive effects of final-offer arbitration (FOA) when disputants have optimistic (i.e., biased) beliefs about the arbitrator's settlement preferences. Optimism is shown to increase the divergence in Nash equilibrium final offers, and the divergence is largest under naive, rather than sophisticated, optimism. Therefore, though FOA rules were instituted to lessen the “chilling” effect of arbitration, FOA interacts with optimism to worsen the chilling effect. Data from controlled laboratory experiments confirm that optimism leads to more divergent final bargaining positions and higher dispute rates. These results highlight the role that de-biasing expectations can play in improving bargaining outcomes.
Efficient synthesis of triazoles from d-arabinose and l-fucose

Abstract The efficient synthesis of sugar-derived triazoles via a one-pot substitution–cyclization–oxidation procedure is presented. Starting from d -arabinose and l -fucose, triazole structures as potential enzyme inhibitors were obtained in six to eight steps.