cssi/SciSciGPT-SciSciNet huggingface dataset:
Water Demand Elasticities: Selection Effects in Meta-Analysis

A meta-analysis of reported water demand elasticities shows that publication selection bias results in water demand estimates that overstate price elasticities. The analysis uses panel data estimators to measure and adjust for publication bias. A random effects estimator is used to derive water demand elasticity estimates that are efficient and unbiased by selection effects. The sample mean elasticity for reported elasticities is -.37%. Once publication bias is removed, the mean elasticity estimate drops to -.08%. Indoor water demand is almost perfectly inelastic. Water demands and their elasticities are heterogeneous in specific uses and locations. Water demand elasticities vary by location, water use type, econometric approach and publication bias. Water use elasticities range up -1.48% for domestic irrigation demand in the southwestern US. Estimated elasticities are also higher when derived with discrete choice data and estimators.
Are Class Actions Unconstitutional

Are class actions unconstitutional? Many people defendants and conservative legislators, not to mention scholars at the American Enterprise Institute would like them to be. For opponents of the class action, Martin Redish's book Wholesale Justice* provides some of the most theoretically sophisticated arguments available. The book is a major contribution both to the scholarly literature on class actions and to the larger political debate about this powerful procedural device. The arguments it presents will surely be debated in courtrooms as well as classrooms.
Plunging into Darkness: Energy Deregulation Collides with Scarcity

In 1969, The Ralph Nader Study Group Report on the Interstate Commerce Commission and Transportation 1Link to the text of the note advocated the substantial deregulation of interstate trucking. The consumer group found that "rate bureaus" of horizontally organized private truckers served as legally authorized cartels to collusively fix shipping rates. The Interstate Commerce Commission (ICC) rubberstamped these regionally formulated industry-set prices. The agency reinforced an anticompetitive structure by issuing narrow licenses of convenience and necessity. These licenses specified the areas a trucker would serve, equipment to be used, commodities to be carried, and even routes to be traversed. A carrier might well have authority to carry photographic film but not developed pictures; rubber hose but not plastic tubing. Common carrier trucking was highly inefficient, with substantial mileage consisting of empty backhauls. And tariffs tended to be set high enough to assure the survival of the most inefficient carriers competing. Nor were assured portions of revenues directed at the "external benefits" often cited to justify industry-dominated public policies, such as safety, reliable availability, or service to rural areas. Trucking consists of relatively small units of production, which are obviously highly mobile. The barriers to entry to increase supply are low. Capacity can adjust to demand relatively quickly. In other words, it is not a high fixed threshold cost industry and not a natural monopoly that might warrant price regulation to prevent monopoly power pricing. The Nader Report was controversial in its time. Consumerists were considered "standard liberals," backers of government intervention in the marketplace. To that point, they had not supported deregulation, instead recommending additional governmental controls to ameliorate external costs flowing from dangerous products, misleading advertising, or other cited market abuses. A new thesis emerged from this and other work: Government used by commercial interests to restrict competition for private gain and public detriment could be the problem. In contrast, the marketplace could be the consumer's friend. But here is the problem: It is not always a faithful friend. Indeed, it occasionally needs a chaperone.
A High Performance Reconfigurable Elliptic Curve Processor for GF(2m)

This work proposes a processor architecture for elliptic curves cryptosystems over fields GF(2m). This is a scalable architecture in terms of area and speed that exploits the abilities of reconfigurable hardware to deliver optimized circuitry for different elliptic curves and finite fields. The main features of this architecture are the use of an optimized bit-parallel squarer, a digit-serial multiplier, and two programmable processors. Through reconfiguration, the squarer and the multiplier architectures can be optimized for any field order or field polynomial. The multiplier performance can also be scaled according to system's needs. Our results show that implementations of this architecture executing the projective coordinates version of the Montgomery scalar multiplication algorithmcan compute elliptic curve scalar multiplications with arbitrary points in 0.21 msec in the field GF(2167). A result that is at least 19 times faster than documented hardware implementations and at least 37 times faster than documented software implementations.
Economic growth, longevity and the epidemiological transition.

This paper integrates investments in health to a standard growth model where physical and human capital investments are the combined engines of growth. It shows the existence of two distinct health regimes separated by an “epidemiological transition.’’ The various patterns of this transition identified in the epidemiological literature can be mapped into the model. The model also leads to the important hypothesis that the epidemiological transition may induce an economy to switch to a modern growth regime.
Fitness Inheritance in the Bayesian Optimization Algorithm

This paper describes how fitness inheritance can be used to estimate fitness for a proportion of newly sampled candidate solutions in the Bayesian optimization algorithm (BOA). The goal of estimating fitness for some candidate solutions is to reduce the number of fitness evaluations for problems where fitness evaluation is expensive. Bayesian networks used in BOA to model promising solutions and generate the new ones are extended to allow not only for modeling and sampling candidate solutions, but also for estimating their fitness. The results indicate that fitness inheritance is a promising concept in BOA, because population-sizing requirements for building appropriate models of promising solutions lead to good fitness estimates even if only a small proportion of candidate solutions is evaluated using the actual fitness function. This can lead to a reduction of the number of actual fitness evaluations by a factor of 30 or more.
Distributed constraint-based local search

Distributed computing is increasingly important at a time when the doubling of the number of transistors on a processor every 18 months no longer translates in a doubling of speed but instead a doubling of the number of cores. Unfortunately, it also places significant conceptual and implementation burden on programmers. This paper aims at addressing this challenge for constraint-based local search (CBLS), whose search procedures typically exhibit inherent parallelism stemming from multistart, restart, or population-based techniques whose benefits have been demonstrated both experimentally and theoretically. The paper presents abstractions that allows distributed CBLS programs to be close to their sequential and parallel counterparts, keeping the conceptual and implementation overhead of distributed computing minimal. A preliminary implementation in Comet exhibits significant speed-ups in constraint satisfaction and optimization applications. The implementation also scales well with the number of machines. Of particular interest is the observation that generic abstractions of CBLS and CP, such as models and solutions, and advanced control structures such as events and closures, play a fundamental role to keep the distance between sequential and distributed CBLS programs small. As a result, the abstractions directly apply to CP programs using multistarts or restarts procedures.
Nonconvexity of the set of hypergraph degree sequences

It is well known that the set of possible degree sequences for a simple graph on $n$ vertices is the intersection of a lattice and a convex polytope. We show that the set of possible degree sequences for a simple $k$-uniform hypergraph on $n$ vertices is not the intersection of a lattice and a convex polytope for $k \geq 3$ and $n \geq k+13$. We also show an analogous nonconvexity result for the set of degree sequences of $k$-partite $k$-uniform hypergraphs and the generalized notion of $\lambda$-balanced $k$-uniform hypergraphs.
A Simplified Approach to Threshold and Proactive RSA

We present a solution to both the robust threshold RSA and proactive RSA problems. Our solutions are conceptually simple, and allow for an easy design of the system. The signing key, in our solution, is shared at all times in additive form, which allows for simple signing and for a particularly efficient and straightforward refreshing process for proactivization. The key size is (up to a very small constant) the size of the RSA modulus, and the protocol runs in constant time, even when faults occur, unlike previous protocols where either the size of the key has a linear blow-up (at best) in the number of players or the run time of the protocol is linear in the number of faults. The protocol is optimal in its resilience as it can tolerate a minority of faulty players. Furthermore, unlike previous solutions, the existence and availability of the key throughout the lifetime of the system, is guaranteed without probability of error.
Inversion of DNA charge by a positive polymer via fractionalization of the polymer charge

Charge inversion of a DNA double helix by an oppositely charged flexible polyelectrolyte (PE) is widely used for gene delivery. It is considered here in terms of discrete charges of DNA. We concentrate on the worst scenario case when in the neutral state of the DNA-PE complex, each of the DNA charges is locally compensated by a PE charge and show that charge inversion exists even in this case. When an additional PE molecule is adsorbed by DNA, its charge gets fractionalized into monomer charges of defects (tails and arches) on the background of the perfectly neutralized DNA. These charges spread all over the DNA eliminating the self-energy of PE. Fractionalization leads to a substantial charge inversion of DNA.
Free Riding and Sales Strategies for the Internet

For many products, Internet sales can free ride oi of the promotional eiort exerted by brick and mortar retailers, leading manufacturers to attempt to control the availability and pricing of their products over the Internet. We examine three categories of products: fragrances, DVD players, and side-by-side refrigerators. Our evidence suggests that manufacturers that limit distribution in the physical world use various mechanisms to limit distribution online. In particular, these manufacturers generally prevent the sale of their products by Internet retailers that oier deep discounts. Furthermore, manufacturer websites tend to charge high prices, suggesting that manufacturers may internalize free rider issues. i. introduction While Internet sales total only about 1.0% of all retail sales in the United States, 1 the rapid growth of Internet commerce suggests that this sales channel will become a signi¢cant factor for many goods. Managing channel con£ict between brick and mortar retailers and Internet retailers is an important and growing problem faced by many manufacturers of branded goods. Manufacturers of branded goods have placed a variety of restrictions on their brick and mortar retailers in an eiort to control freeriding on the sales and promotional eiorts of retailers. The emergence of the Internet as a new distribution channel requires manufacturers to develop restrictions on Internet retailers to control free riding. In this paper, we investigate empirically the extent to which manufacturers of three types of branded goods appear to control the pricing and
Fundus Autofluorescence and Optical Coherence Tomographic Findings in Acute Zonal Occult Outer Retinopathy

Purpose:The purpose of this study was to investigate the fundus autofluorescence and optical coherence tomography findings in eyes with acute zonal occult outer retinopathy (AZOOR).Methods:A retrospective observational case series of the fundus autofluorescence and spectral domain optical coherence
Mechanism Design with Limited Information: The Case of Nonlinear Pricing

We analyze the canonical nonlinear pricing model with limited information. A seller offers a menu with a finite number of choices to a continuum of buyers with a continuum of possible valuations. By revealing an underlying connection to quantization theory, we derive the optimal finite menu for the socially efficient and the revenue-maximizing mechanism. In both cases, we provide an estimate of the loss resulting from the usage of a finite n-class menu. We show that the losses converge to zero at a rate proportional to 1/n 2 as n becomes large.
Is Relational Exchange Possible in the Absence of Reputations and Repeated Contact

Experimental methods are used to study two central components of an incomplete contract: the ex post process of negotiation, which fixes contract terms and surplus shares in response to stochastic shocks, and the ex ante process of transaction-specific investment made in anticipation of future surplus shares. The 2 x 2 treatment design features either high or low discount rates in an alternating-offer bargaining setting, and transaction-specific investments that are either commonly observable or private information and thus unobservable. The analysis finds results consistent with the notion that despite random and anonymous matching of contracting parties, and the noncontractability of investments, parties index their surplus sharing agreements to transactionspecific investments when these investments are observable. Parties who invest relatively more tend to receive larger shares of ex post surplus, which in turn promotes additional investment and so overcomes part of the underinvestment problem inherent to these sort of sharing contracts. The analysis suggests that relational exchange is possible in settings where individual reputations and frequently repeated contact are absent, and thus supports Macneil's claim that social norms of equity are central to relational exchange.
Compiling constraint handling rules for efficient tabled evaluation

Tabled resolution, which alleviates some of Prolog's termination problems, makes it possible to create practical applications from high-level declarative specifications. Constraint Handling Rules (CHR) is an elegant framework for implementing constraint solvers from high-level specifications, and is available in many Prolog systems. However, applications combining the power of these two declarative paradigms have been impractical since traditional CHR implementations interact poorly with tabling. In this paper we present a new (set-based) semantics for CHR which enables efficient integration with tabling. The new semantics coincides with the traditional (multi-set-based) semantics for a large class of CHR programs. We describe CHRd, an implementation based on the new semantics. CHRd uses a distributed constraint store that can be directly represented in tables. Although motivated by tabling, CHRd works well also on non-tabled platforms. We present experimental results which show that, relative to traditional implementations, CHRd performs significantly better on tabled programs, and yet shows comparable results on non-tabled benchmarks.
Selling Your Torts: Creating a Market for Tort Claims and Liability

If an exchange between two parties is voluntary, it will not take place unless both believe they will benefit from it. Most economic fallacies derive from the neglect of this simple insight, from the tendency to assume that there is a fixed pie, that one party can gain only at the expense of another.
Combining Competing Language Understanding Approaches in an Intelligent Tutoring System

When implementing a tutoring system that attempts a deep understanding of students’ natural language explanations, there are three basic approaches to choose between; symbolic, in which sentence strings are parsed using a lexicon and grammar; statistical, in which a corpus is used to train a text classifier; and hybrid, in which rich, symbolically produced features supplement statistical training. Because each type of approach requires different amounts of domain knowledge preparation and provides different quality output for the same input, we describe a method for heuristically combining multiple natural language understanding approaches in an attempt to use each to its best advantage. We explore two basic models for combining approaches in the context of a tutoring system; one where heuristics select the first satisficing representation and another in which heuristics select the highest ranked representation.
The constitution of thalicarpine.

Reinvestigation on the constitution of thalicarpine, previously, isolated from Thalictrum and Hernandia species, was descrived. Ullmann condensation product of L-6'-bromolaudanosine and N-methyllaurotetanine was identified with natural thalicarpine. Accordingly, the revised constitution of thalicarpine was established to have the formula IX.
FOIL-D: Efficiently Scaling FOIL for Multi-relational Data Mining of Large Datasets

Multi-relational rule mining is important for knowledge discovery in relational databases as it allows for discovery of patterns involving multiple relational tables. Inductive logic programming (ILP) techniques have had considerable success on a variety of multi-relational rule mining tasks, however, most ILP systems do not scale to very large datasets. In this paper we present two extensions to a popular ILP system, FOIL, that improve its scalability. (i) We show how to interface FOIL directly to a relational database management system. This enables FOIL to run on data sets that previously had been out of its scope. (ii) We describe estimation methods, based on histograms, that significantly decrease the computational cost of learning a set of rules. We present experimental results that indicate that on a set of standard ILP datasets, the rule sets learned using our extensions are equivalent to those learned with standard FOIL but at considerably less cost.
Infrastructure gap in South Asia : infrastructure needs, prioritization, and financing

If the South Asia region hopes to meet its development goals and not risk slowing down or even halting growth, poverty alleviation, and shared prosperity, it is essential to make closing its huge infrastructure gap a priority. Identifying and addressing gaps in the data on expenditure, access, and quality are crucial to ensuring that governments make efficient, practical, and effective infrastructure development choices. This study addresses this knowledge gap by focusing on the current status of infrastructure sectors and geographical disparities, real levels of investment and private sector participation, deficits and proper targets for the future, and bottlenecks to expansion. The findings show that the South Asia region needs to invest between US$1.7 trillion and US$2.5 trillion (at current prices) to close its infrastructure gap. If investments are spread evenly over the years until 2020, the region needs to invest between 6.6 and 9.9 percent of 2010 gross domestic product per year, an estimated increase of up to 3 percentage points from the 6.9 percent of gross domestic product invested in infrastructure by countries in the region in 2009. Given the enormous size of the region's infrastructure deficiencies, it will need a mix of investment in infrastructure stock and supportive reforms to close its infrastructure gap. One major challenge will be prioritizing investment needs. Another will be choosing optimal forms of service provision, including the private sector's role, and the decentralization of administrative functions and powers.
Biochemical production of other bioalcohols: biomethanol, biopropanol, bioglycerol, and bioethylene glycol.

Abstract: Bioethanol and biobutanol are the two most commonly discussed bioalcohols for fuel purposes. However, other alcohols can be produced from biomass. This chapter will introduce other bioalcohols and discuss their production. These bioalcohols include: biomethanol, biopropanol, bioglycerol, bioethylene glycol, as well as branched chain bioalcohols and other theoretical biofuels. It will compare the advantages and disadvantages of employing different fuels on the basis of both availability and ease of production as well as chemical, biological, and physical properties of these fuels.
A new NC-algorithm for finding a perfect matching in d -regular bipartite graphs when d is small

The perfect matching problem for general graphs reduces to the same for regular graphs. Even finding an NC algorithm for the perfect matching problem in cubic (3-regular) or 4-regular graphs will suffice to solve the general problem (see [DK 92]). For regular bipartite graphs an NC algorithm is already known [LPV 81], while [SW 96] give an NC algorithm for cubic-bipartite graphs. We present a new and conceptually simple parallel algorithm for finding a perfect matching in d-regular bipartite graphs. When d is small (polylogarithmic) our algorithm in fact runs in NC. In particular for cubic-bipartite graphs, our algorithm as well as its analysis become much simpler than the previously known algorithms for the same. Our techniques are completely different from theirs. Interestingly, our algorithm is based on a method used by [MV 00] for finding a perfect matching in planar-bipartite graphs. So, it is remarkable that, circumventing the planarity, we could still make the same approach work for a non-planar subclass of biparitite graphs.
Complex function sets improve symbolic discriminant analysis of microarray data

Our ability to simultaneously measure the expression levels of thousands of genes in biological samples is providing important new opportunities for improving the diagnosis, prevention, and treatment of common diseases. However, new technologies such as DNA microarrays are generating new challenges for variable selection and statistical modeling. In response to these challenges, a genetic programming-based strategy called symbolic discriminant analysis (SDA) for the automatic selection of gene expression variables and mathematical functions for statistical modeling of clinical endpoints has been developed. The initial development and evaluation of SDA has focused on a function set consisting of only the four basic arithmetic operators. The goal of the present study is to evaluate whether adding more complex operators such as square root to the function set improves SDA modeling of microarray data. The results presented in this paper demonstrate that adding complex functions to the terminal set significantly improves SDA modeling by reducing model size and, in some cases, reducing classification error and runtime. We anticipate SDA will be an important new evolutionary computation tool to be added to the repertoire of methods for the analysis of microarray data.
Bargaining Power in Relational Contracts: An Experimental Study

This paper provides experimental evidence of the economic impact from shifting bargaining power in relational contracts. I implement an experimental design that adjusts the bargaining power of sellers (agents) and the enforceability of the contract. I nd that the vast majority of contracts take the form of eciency wage contracts instead of contingent performance contracts when enforcement is partially incomplete and sellers have more bargaining power than buyers. The total contracted and actual compensation increase with the bargaining power of the sellers. However, sellers’ prots are found to increase only if a part of the total payment is third-party enforceable. In this case, observed surplus and eciency are lower than predictions. When no part of a contract is third-party enforceable, more cooperative relationships emerge, exhibiting higher quality provision resulting in higher surplus and eciency while rent sharing is lower. The result is explained by the stronger buyer’s deviation, conrming predictions derived in Cordero Salas (2010). The results here provide insight into the economic consequences of enacting policies that improve the bargaining conditions of weaker parties in market settings relying on self-enforcement from underdeveloped legal institutions.
Open loci of graded modules

Let A = ⊕ i∈N A i be an excellent homogeneous Noetherian graded ring and let M = ⊕ n∈Z M n be a finitely generated graded A-module. We consider M as a module over A 0 and show that the (S k )-loci of M are open in Spec(A 0 ). In particular, the Cohen-Macaulay locus U 0 CM = {p ∈ Spec(A 0 ) | M p is Cohen-Macaulay} is an open subset of Spec(A 0 ). We also show that the (S k )-loci on the homogeneous parts M n of M are eventually stable. As an application we obtain that for a finitely generated Cohen-Macaulay module M over an excellent ring A and for an ideal I C A which is not contained in any minimal prime of M, the (S k )-loci for the modules M/I n M are eventually stable.
Intersection numbers in the curve complex via subsurface projections

A classical inequality which is due to Lickorish and Hempel says that the distance between two curves in the curve complex can be measured by their intersection number. In this paper, we show a converse version; the intersection number of two curves can be measured by the sum of all subsurface projection distances between them. As an application of this result, we obtain a coarse decreasing property of the intersection numbers of the multicurves contained in tight multigeodesics. Furthermore, by using this property, we give an algorithm for determining the distance between two curves in the curve complex. Indeed, such algorithms have also been found by Birman–Margalit–Menasco, Leasure, Shackleton, and Webb: we will briefly compare our algorithm with some of their algorithms, for detailed quantitative comparison of all known algorithms including our algorithm, we refer the reader to the paper of Birman–Margalit–Menasco [1].
Information Frictions in Trade

It is costly to learn about market conditions elsewhere, especially in developing countries. This paper examines how such information frictions affect trade. Using data on regional agricultural trade in the Philippines, I first document a number of observed patterns in trade flows and prices that suggest the presence of information frictions. I then incorporate information frictions into a perfect competition trade model by embedding a process whereby heterogeneous producers engage in a costly sequential search process to determine where to sell their produce. I show that introducing information frictions reconciles the theory with the observed patterns in the data. Structural estimation of the model finds that information frictions are quantitatively important: roughly half the observed regional price dispersion is due to information frictions. Furthermore, incorporating information frictions improves the out-of-sample predictive power of the model.
Crecimiento sustantivo y organización innovadora: nuevas categorías para la investigación en educación superior.

The existing international literature on higher education centers on the transition from elite to mass higher education, the changing relationship between ...
Dynamics of a Service Economy Driven by Random Transactions

Agents buy and sell services. All services are of equal quality. Buyers choose sellers at random. Monetary and fiscal policies are imposed by a central bank and a central government. Credit is supplied by a commercial banking system. Propensities to buy, sell, and lend depend on account balances, interest rates, tax rates and loan default rates. Computer simulations track weekly sales, loans, account balances, commercial bank profits, solvency and compliance with reserve requirements, and government debt. The model of this economy is fully specified by a computer program. The program allows the user to explore the effects of parameter changes. Monetary and fiscal policies are implemented by choices of parameters such as interest rates and reserve requirements, and government tax and spending rates. Credit supply, consumer confidence, and loan default rates strongly affect the behavior of the economy in terms of sales.
Multispectral multisensor image fusion using wavelet transforms

Fusion techniques can be applied to multispectral and higher spatial resolution panchromatic images to create a composite image that is easier to interpret than the individual images. Wavelet transform-based multisensor, multiresolution fusion was applied to Landsat thematic mapper multispectral and coregistrated higher resolution SPOT panchromatic images. The objective was to obtain increased spatial resolution, false color composite products to support the interpretation of land cover types wherein the spectral characteristics of the imagery are preserved to provide the spectral clues needed for interpretation. Since the fusion process should not introduce artifacts, a shift invariant implementation of the discrete wavelet transform (SIDWT) was used. These results were compared with those using the shift variant, discrete wavelet transform (DWT). Overall, the process includes a hue, saturation, and value color space transform to minimize color changes, and a reported point- wise maximum selection rule to combine transform coefficients. The performance of fusion based on the SIDWT and DWT was evaluated with a simulated TM 30-m spatial resolution test image and a higher resolution reference. Simulated imagery was made by blurring higher resolution color-IR photography with the TM sensors' point spread function. The SIDWT based technique produced imagery with fewer artifacts and lower error between fused images and the full resolution reference. Image examples with TM and SPOt 10-m panchromatic illustrate the reduction in artifacts due to the SIDWT based fusion.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Characteristics and Production Costs of U.S. Cotton Farms, 2007

Agricultural Resource Management Survey (ARMS) data for 2007 highlight the production\r practices and costs related to the cotton enterprise, as well as the characteristics of\r U.S. cotton farm operations. Combining ARMS data with ERS cost-of-cotton production\r estimates for 2007 provides a 1-year snapshot of cotton producers. For instance, low-cost producers reported higher yields and lower levels of major inputs per planted cotton acre than mid- and high-cost producers in 2007. Southwest producers accounted for a larger share of the smaller U.S. cotton crop in 2007 due to their lower cotton production costs and lack of alternative crops. Most U.S. cotton is produced on very large diversified farm\r operations, with cotton often constituting a small share of these operations’ total acres. In contrast, producers with larger cotton enterprises in 2007 relied more on their cotton crop, making them vulnerable to changes in cotton prices or yields. These producers, however, were also more likely to offset greater risks by purchasing revenue insurance on cotton.
Fabrication of micro-magnetic traps for cold neutral atoms

Many proposals for quantum information processing require precise control over the motion of neutral atoms, as in the manipulation of coherent matter waves or the confinement and localization of individual atoms. Patterns of micron-sized wires, fabricated lithographically on a flat substrate, can conveniently produce large magnetic-field gradients and curvatures to trap cold atoms and to facilitate the production of Bose-Einstein condensates. The intent of this paper is to provide the researcher who has access to a standard clean-room enough information to design and fabricate such devices.
A New View of Baryon Symmetric Cosmology Based on Grand Unified Theories

It has been proposed by Heisenberg (1967) and Fritzsch and Minkowski (1975) that the fundamental Lagrangian of nature should be completely symmetric and that all observed asymmetries are due to asymmetries in the vacuum state. Thus, all asymmetries would arise from spontaneous symmetry breaking of the ultimate grand unified theory. The full symmetry of the theory is expected to hold in the interactions above some critical temperature Tc. Below that critical temperature, multiple vacuum states can be arrived at by the process of spontaneous symmetry breaking. Each “state” corresponds to a unique set of vacuum expectation-values of scalar fields (or their equivalent) which, having been randomly determined through a dynamical instability, themselves determine a new, selfcontained gauge-field theory. Thus, a theory of nature is arrived at randomly from a number of equally probable theories, the original Lagrangian not having uniquely determined the “low-temperature” physics which we observe at our accelerators.
Dip moveout of converted waves and parameter estimation in transversely isotropic media

For transverse isotropy with a vertical symmetry axis (VTI media), P-wave reflection data alone are insufficient for building velocity models in depth. Here, we show that all parameters of VTI media responsible for propagation of P- and SV-waves (the P-wave and S-wave vertical velocities VP0 and VS0 and the anisotropic parameters e and δ) can be obtained by combining P-wave traveltimes with the moveout of PS-waves converted at a horizontal and dipping interface. Using converted modes, rather than pure S-waves, avoids the need for expensive shear-wave excitation on land and makes the method suitable for offshore exploration. The inversion algorithm is based on a new analytic description of the dip moveout of PS-waves developed for symmetry planes of anisotropic media (and for any vertical plane in models with weak azimuthal anisotropy). The common-midpoint (CMP) traveltime–offset relationship, derived in a parametric form and represented through the components of the slowness vector of the P- and S-waves, makes it possible to compute the moveout curve of the PS-wave without two-point ray tracing. This formalism also leads to closed-form solutions for moveout attributes, such as the coordinates (xmin, tmin) of the traveltime minimum, the normal-moveout (NMO) velocity defined at x = xmin and the slope of the moveout curve (apparent slowness) at zero offset. The parameter-estimation algorithm operates with reflection moveout of P- and PS-waves from a horizontal and dipping reflector. The NMO velocities of P- and PS-waves from horizontal events and the ratio of the corresponding zero-offset traveltimes yield three equations for the four unknown medium parameters. The remaining parameter is found from an overdetermined system of equations that includes the P-wave NMO velocity and moveout attributes of the PS-wave for a dipping event. Numerical analysis shows that the PS-wave dip-moveout signature plays a crucial role in obtaining accurate estimates of the anisotropic parameters. The joint inversion of P and PS data provides the necessary information not only for P-wave depth imaging in VTI media, but also for the processing of PS-waves, including re-sorting of PS traces into common-reflection-point gathers and transformation to zero offset (TZO).
Does retirement improve health and life satisfaction

We utilize panel data from the Health and Retirement Study to investigate the impact of retirement on physical and mental health, life satisfaction, and health care utilization. Because poor health can induce retirement, we instrument for retirement using eligibility for Social Security and employer-sponsored pensions and coverage by the Social Security earnings test. We find strong evidence that retirement improves reported health, mental health, and life satisfaction. In addition, we find evidence of improvements in functional limitations in the long run. Although the impact on life satisfaction occurs within the first 4 years of retirement, many of the improvements in health show up four or more years later, consistent with the view that health is a stock that evolves slowly. We find no evidence that the health improvements are driven by increased health care utilization. In fact, results suggest decreased utilization in some categories.
Mark-Up Distortions and Endogenous Misallocation

Income differences across countries are to a large degree driven by differences in aggregate TFP. Recently it has been argued that part of these differences are due to misallocation of factor across firms. In this paper we propose a structural model of this degree of misallocation. Our model is one where monopolistic competition across firms generates non-constant mark-ups, which reduce aggregate TFP relative to the competitive benchmark. Equilibrium mark-ups depend only on the distribution of firm-level productivity, which evolves endogenously according to a Schumpeterian process of creative destruction. This provides the link between the economy's innovation environment and the equilibrium degree of misallocation. In particular, the economy's entry intensity is a sufficient statistic for the invariant distribution of mark-ups and their TFP consequences. If entry is more intense, aggregate TFP is higher, as product market competition reduces the distorting effect of mark-ups. This provides a new channel how impediments to firm entry, like entry costs, reduce allocative efficiency, aggregate TFP and income per capita.
Design Considerations for Lightweight Space Radiators Based on Fabrication and Test Experience With a Carbon-Carbon Composite Prototype Heat Pipe

Summary This report discusses the design implications for spacecraftradiators made possible by the successful fabrication andproof-of-concept testing of a graphite-fiber-carbon-matrix com-posite (i.e., carbon-carbon (C-C)) heat pipe. The prototype heatpipe, or space radiator element, consists of a C-C compositeshell with integrally woven fins. It has a thin-walled furnace-brazed metallic (Nb- 1%Zr) liner with end caps for containmentof the potassium working fluid. A short extension of this liner,at increased wall thickness beyond the C-C shell, forms theheat pipe evaporator section which is in thermal contact withthe radiator fluid that needs to be cooled. During the fabricationprocess the C_ shell condenser section was exposed to anatomic oxygen (AO) ion source for a total AO fluence of4×102o atoms/cm 2, thereby raising its surface emissivity forheat radiation to a value of 0.85 to 0.90 at design operatingtemperatures of 700 to 800 K. The prototype heat pipe wasextensively tested from startup at ambient conditions, with theworking fluid initially in the frozen state, to a condensertemperature of nearly 700 K. Post-test inspection showed theheat pipe to be in excellent condition after several thermalcycles from ambient to operating temperature.The report also discusses the advantage of segmented spaceradiator designs utilizing heat pipe elements, or segments, intheir survivability to micrometeoroid damage. This survivabil-ity is further raised by the use of condenser sections withattached fins, which also improve the radiation heat transferrate. Since the problem of heat radiation from a fin does not lenditself to a closed analytical solution, a derivation of the govern-ing differential equation and boundary conditions is given inappendix A, along with solutions for rectangular and parabolicfin profile geometries obtained by use of a finite differencecomputer code written by the author.From geometric and thermal transport properties of the C-Ccomposite heat pipe tested, a specific radiator mass of 1.45 kg/m 2 can be derived. This is less than one-fourth the specific massof present day satellite radiators. Using composites with ultra-high conductivity would further reduce the area density ofspacecraft radiators, and utilizing alternate heat pipe fluids withcompatible liner materials would extend the C-C heat pipetechnology to a wide range of temperatures and applications.
Permutation Based Inference

Permutation tests were developed to free analysts of unwarranted assumptions about the mathematical form of response distributions and are nearly synonymous with nonparametric or distribution-free tests. Keywords: exchangeability; reference distribution; frequency-based inference; conditional tests
Configuration spaces of convex and embedded polygons in the plane

This paper concerns the topology of configuration spaces of linkages whose underlying graph is a single cycle. Assume that the edge lengths are such that there are no configurations in which all the edges lie along a line. The main results are that, modulo translations and rotations, each component of the space of convex configurations is homeomorphic to a closed Euclidean ball and each component of the space of embedded configurations is homeomorphic to a Euclidean space. This represents an elaboration on the topological information that follows from the convexification theorem of Connelly, Demaine, and Rote.
Wake interference for a heated oscillating cylinder

Penney and Jefferson (1966) have studied heat transfer from an oscillating, horizontal wire. The present investigation has the objective to determine the governing parameters which indicate when interaction between an oscillating circular cylinder and its wake will reduce the apparent heat transfer coefficient in quasi-steady conditions, taking into account, if possible, also the determination of the approximate magnitude of the reduction. A definition is provided of a nondimensional vertical mass flux, representing the induced flow due to heating of the stagnant fluid. It is hypothesized that the flux is related to a natural convection parameter which describes the heating of the wake. For oscillation of a circular cylinder in air under the conditions studied, it is found that the application of a cross-flow correlation in a quasi-steady, transient analysis predicts heat transfer parameters in close agreement with experiment over a certain range, provided interaction with the heated wake is avoided.
Solar radio emission.

The subject of solar radio emission is quite broad and has been reviewed repeatedly in articles and books (Wild et al., 1963; Kundu, 1965; Zheleznyakov, 1970; Wild and Smerd, 1972; Rosenberg, 1976; Smerd, 1976a; Kruger, 1979; Melrose, 1980a). In addition, recent conference proceedings include issue 9 of Radiophysics and Quantum Electronics 20 (1977) and ‘Radio Physics of the Sun’, IAU Symposium 86 (Reidel, Dordrecht, 1980). Entire books exist on specialized topics, and we shall refer to them as necessary.
Uniformity is Weaker than Semi-Uniformity for Some Membrane Systems

We investigate computing models that are presented as families of finite computing devices with a uniformity condition on the entire family. Examples of such models include Boolean circuits, membrane systems, DNA computers, chemical reaction networks and tile assembly systems, and there are many others. However, in such models there are actually two distinct kinds of uniformity condition. The first is the most common and well-understood, where each input length is mapped to a single computing device (e.g. a Boolean circuit) that computes on the finite set of inputs of that length. The second, called semi-uniformity, is where each input is mapped to a computing device for that input (e.g. a circuit with the input encoded as constants). The former notion is well-known and used in Boolean circuit complexity, while the latter notion is frequently found in literature on nature-inspired computation from the past 20 years or so. Are these two notions distinct? For many models it has been found that these notions are in fact the same, in the sense that the choice of uniformity or semi-uniformity leads to characterisations of the same complexity classes. In other related work, we showed that these notions are actually distinct for certain classes of Boolean circuits. Here, we give analogous results for membrane systems by showing that certain classes of uniform membrane systems are strictly weaker than the analogous semi-uniform classes. This solves a known open problem in the theory of membrane systems. We then go on to present results towards characterising the power of these semi-uniform and uniform membrane models in terms of NL and languages reducible to the unary languages in NL, respectively.
Use of a Satellite Multifrequency Radiometer to Determine Attenuation Suffered by a Satellite Radar

The SEASAT Active Scatterometer System (SASS) is a multibeam radar designed to measure two radar backscatter signals from the sea and from them determine the wind vector. When condensed water is present in clouds and rain, the return signal is attenuated by the atmosphere and must be corrected before a wind determination can be made. The SEASAT Scanning Multifrequency Microwave Radiometer (SMMR) provided the opportunity to measure the attenuation.
Voyager Design and Flight Loads Comparison

Estimates of flight loads for Voyager 1 and Voyager 2 are summarized. These member loads are obtained by using the measured flight accelerations at the launch vehicle/spacecraft interface as forcing functions for the Voyager mathematical model. The flight loads are compared to the Voyager design loads obtained from the shock spectra/impedance method and to the loads obtained using space vehicle transient loads analysis. Finally, based on these data, an assessment of the shock spectra/impedance loads method used for Voyager is presented. N the late summer of 1977, two spacecraft, Voyager A and B (later redesignated as Voyager 2 and Voyager 1, respectively) were successfully launched by the Titan-Centaur launch vehicle to begin their journeys to the planets Jupiter and Saturn. The slower Voyager 2, launched first, may be targeted on past Saturn to explore Uranus. During the powered flight of the Voyager space vehicle, the accelerations at the interface between the spacecraft and the launch vehicle were recorded as a function of time. Applying these interface accelerations to the base of the spacecraft structural model, the member loads can be evaluated. The member loads obtained by this method represent best estimates of the actual loads experienced by the spacecraft during the powered flight. In the context of this report these loads will be referred to as flight loads. The comparison of the flight loads to the design loads is the subject of this report. Such a comparison allows the evaluation of the loads methodology used to design the Voyager spacecraft and should prove valuable for future projects. The methodology for the establishment of spacecraft loads is strongly influenced by project constraints which include the cost, schedule, and allowable weight. The most rigorous approach is the transient loads analysis, which requires a composite mathematical model of the spacecraft and launch vehicle. The structural member loads for the entire composite structure are computed by applying the forcing functions, which represent various dynamic environments during the mission, to the composite model. Although this method, which was used to design the Viking Orbiter spacecraft,1'2 ideally leads to a lightweight design, it is costly and time consuming due to complex interfaces involving many organizations. To reduce complexity and cost, a shock spectra/impedance method 3 was used to design the Voyager spacecraft structural system. This method utilizes envelopes of shock spectra of launch vehicle accelerations obtained