cssi/SciSciGPT-SciSciNet huggingface dataset:
Fractal symbolic analysis

Modern compilers perform wholesale restructuring of programs to improve their efficiency. Dependence analysis is the most widely used technique for proving the correctness of such transformations, but it suffers from the limitation that it considers only the memory locations read and written by a statement, and does not assume any particular interpretation for the operations in that statement. Exploiting the semantics of these operations permits more transformations to be proved correct, and is critical for automatic restructuring of codes such as LU with partial pivoting.One approach to exploiting the semantics of program operations is symbolic analysis and comparison of programs. In principle, this technique is very powerful, but in practice, it is intractable for all but the simplest programs.In this paper, we propose a new form of symbolic analysis and comparison of programs which is appropriate for use in restructuring compilers. Fractal symbolic analysis compares a program and its transformed version by repeatedly simplifying these programs until symbolic analysis becomes tractable while ensuring that equality of the simplified programs is sufficient to guarantee equality of the original programs.Fractal symbolic analysis combines some of the power of symbolic analysis with the tractability of dependence analysis. We discuss a prototype implementation of fractal symbolic analysis, and show how it can be used to solve the long-open problem of verifying the correctness of transformations required to improve the cache performance of LU factorization with partial pivoting.
A pilot-scale distillation facility for digital computer control research

Abstract A new pilot-scale multicomponent distillation facility and associated computer control system are described. The control system design utilizes a hierarchical structure, with a microcomputer for direct digital control of secondary process variables and a general-purpose, real-time computer for high-level control of the primary variables. The facility is used for advanced process control research and real-time system instruction. Some typical results incorporating a new multivariable predictive control algorithm are presented.
Parts and differences

Part/whole is said in many ways: the leg is part of the table, the subset is part of the set, rectangularity is part of squareness, and so on. Do the various flavors of part/whole have anything in common? They may be partial orders, but so are lots of non-mereological relations. I propose an “upward difference transmission” principle: x is part of y if and only if x cannot change in specified respects while y stays the same in those respects.
Probabilistic analysis of Wiedemann's algorithm for minimal polynomial computation

Blackbox algorithms for linear algebra problems start with projection of the sequence of powers of a matrix to a sequence of vectors (Lanczos), a sequence of scalars (Wiedemann) or a sequence of smaller matrices (block methods). Such algorithms usually depend on the minimal polynomial of the resulting sequence being that of the given matrix. Here exact formulas are given for the probability that this occurs. They are based on the generalized Jordan normal form (direct sum of companion matrices of the elementary divisors) of the matrix. Sharp bounds follow from this for matrices of unknown elementary divisors. The bounds are valid for all finite field sizes and show that a small blocking factor can give high probability of success for all cardinalities and matrix dimensions.
A simplified scanning tunneling microscope for surface science studies

A compact, reliable scanning tunneling microscope (STM) is described which provides atomic scale resolution and is intended for surface science studies. The novel design features consist of a rigid contact between the sample and piezoelectric scanner, together with the use of a pivot and lever arm to achieve both coarse and fine mechanical motion. Topological images of the Si(111) 7 × 7 surface are presented showing some point and extended defects. The bias dependence of these topographs is demonstrated and briefly discussed.
Numerical Study of Flow and Temperature Stratifications in a Liquid Thermal Storage Tank

A two-dimensional, time-dependent mathematical model has been developed to investigate the flow and temperature stratification phenomena in a liquid thermal storage tank for a solar energy system. This model is based on the principles of both natural and forced convective heat transfer. To obtain the numerical solution for this set of nonlinear partial differential equations, an improved Alternative Direction Implicit (ADI) scheme was developed, which enables us to obtain solutions for very large Grashof and Reynolds numbers for the first time. In this analysis, we present the numerical results on the flow patterns and temperature distributions in a liquid storage tank for various Reynolds and Grashof numbers together with the numerical scheme.
Obscuration and origin of nuclear x-ray emission in Fr I radio galaxies

We present X-ray observations of the nuclear region of 25 Fanaroff-Riley type I (FR I) radio galaxies from the 3CRR and B2 catalogs, using data from the Chandra and XMM-Newton archives. We find the presence of a X-ray central compact core (CCCX) in 13/25 sources; in 3/25 sources the detection of a CCCX is uncertain, while in the remaining 9/25 sources no CCCX is found. All the sources are embedded in a diffuse soft X-ray component, generally on kiloparsec scales, which is in agreement with the halo of the host galaxy and/or with the intracluster medium. The X-ray spectra of the cores are described by a power law with photon indices Γ = 1.1-2.6. In eight sources excess absorption over the Galactic value is detected, with rest-frame column densities N ~ 1020-1021 cm-2; thus, we confirm the previous claim, based on optical data, that most FR I radio galaxies lack a standard optically thick torus. We find significant correlations between the X-ray core luminosity and the radio and optical luminosities, suggesting that at least a fraction of the X-ray emission originates in a jet; however, the origin of the X-rays remains ambiguous. If the X-ray emission is entirely attributed to an isotropic, accretion-related component, we find very small Eddington ratios, Lbol/LEdd ~ 10-3 to 10-8, and we calculate the radiative efficiency to be η ~ 10-2 to 10-6 on the basis of the Bondi accretion rates from the spatial analysis. This suggests that radiatively inefficient accretion flows are present in the cores of low-power radio galaxies.
Modeling maintenance of long-term potentiation in clustered synapses: long-term memory without bistability.

Memories are stored, at least partly, as patterns of strong synapses. Given molecular turnover, how can synapses maintain strong for the years that memories can persist? Some models postulate that biochemical bistability maintains strong synapses. However, bistability should give a bimodal distribution of synaptic strength or weight, whereas current data show unimodal distributions for weights and for a correlated variable, dendritic spine volume. Thus it is important for models to simulate both unimodal distributions and long-term memory persistence. Here a model is developed that connects ongoing, competing processes of synaptic growth and weakening to stochastic processes of receptor insertion and removal in dendritic spines. The model simulates long-term (>1 yr) persistence of groups of strong synapses. A unimodal weight distribution results. For stability of this distribution it proved essential to incorporate resource competition between synapses organized into small clusters. With competition, these clusters are stable for years. These simulations concur with recent data to support the “clustered plasticity hypothesis” which suggests clusters, rather than single synaptic contacts, may be a fundamental unit for storage of long-term memory. The model makes empirical predictions and may provide a framework to investigate mechanisms maintaining the balance between synaptic plasticity and stability of memory.
The linearized system for isometric embeddings and its characteristic variety

Abstract In this paper we prove a conjecture of Bryant, Griffiths, and Yang concerning the characteristic variety for the determined isometric embedding system. In particular, we show that the characteristic variety is not smooth for any dimension greater than 4. This is accomplished by introducing a smaller yet equivalent linearized system, in an appropriate way, which facilitates analysis of the characteristic variety.
Revenue and Cost Uncertainty, Generalized Mean-Variance, and the Linear Complementarity Problem

Although their conclusion is not satisfactory (and is unacceptable to me), the comment by Dubman, Gunter, and Miller (DGM) is rather interesting and has given me the opportunity of rethinking the entire problem of generalized mean-variance since it was proposed in 1979. DGM make essentially two points: (a) The symmetric quadratic programming (SQP) model, as applied to risky output prices and input supplies, allows for an increase of input availabilities over and above the expected input quantities. This possibility is regarded by DGM as "contrary to the conventional assumptions of risk aversion" (p. 806). They think that a "wrong" sign is associated with the input risk adjustment term in the primal constraints. (b) The value of the objective function under input uncertainty and risk aversion is always higher than the corresponding value under risk neutrality. Again, DGM attribute this behavior of the model to the same "wrong" sign. But since changing the sign causes the collapse of the Karush-Kuhn-Tucker conditions, they conclude that the model is invalid for dealing with stochastic input supplies and recommend its abandonment in favor of traditional chance-constrained programming (p. 808).
The economics of a stock pollutant: Aldicarb on Long Island

This paper develops a dynamic model of groundwater contamination by the pesticide aldicarb on eastern Long Island. We estimate what the likely concentration would have been under static profit maximization and the marginal damage coefficient implied by the New York State health standard of 7 ppb. Based on our model, it appears that the concentration of aldicarb will not decline below 7 ppb until 1996 and that the shadow price of the current health standard is about $475,000 per year.
Error analysis by numerical simulation for a three-color pyrometer assuming a blackbody spectrum and a wavelength- and temperature-dependent emissivity

A numerical method devised to test ratio pyrometers has been used to explore the fitting of a blackbody spectrum and an emissivity model that assumes linear wavelength dependence and arbitrary temperature dependence. The slope and intercept coefficients for the emissivity and the temperature form three unknowns. The equations for the output of the three channels can be solved simultaneously for the emissivity coefficients and the temperature at any given time using the corresponding measured channel outputs. The stability of the solution is tested as a function of the temperature and equipment characteristics.
Analysis of Iron and Magnet Losses in Surface-Permanent-Magnet Machines Resulting From Injection-Based Self-Sensing Position Estimation

This paper presents a systematic analysis of iron and magnet losses in surface-permanent-magnet (SPM) machines for the position estimation using high-frequency (HF) signal injection. Standard SPM machines with cylindrical rotors are analyzed. It is shown that the magnet eddy current loss due to the superimposed HF signal should be considered for SPM-machine injection-based position estimation. With a proper machine design, the resulting HF armature flux linkage in the magnet can convert to the HF leakage flux in the stator. The decreased magnet eddy current loss can be achieved, leading to better performance on both power conversion and injection-based position estimation. This paper includes the experimental evaluation of two SPM machines with different winding configurations.
Acoustic Emission Analysis of Nanoindentation-Induced Fracture Events

Monitoring of acoustic emission activity is employed to characterize the initiation and progression of local failure processes during nanoindentation-induced fracture. Specimens of various brittle materials are loaded with a cube-corner indenter and acoustic emission activity is monitored during the entire loading and unloading event using a transducer mounted inside the specimen holder. As observed from the nanoindentation and acoustic emission response, there are fundamental differences in the fracture behavior of the various materials. Post-failure observations are used to identify particular features in the acoustic emission signal that correspond to specific types of fracture events. Furthermore, analysis of the parametric and transient acoustic emission data is used to establish the crack-initiation threshold, crack-arrest threshold, and energy dissipation during failure. It is demonstrated that the monitoring of acoustic emission signals yields both qualitative and quantitative information regarding highly localized failure events in brittle materials.
Charm Production in Deep Inelastic Scattering from Threshold to High Q 2

Charm final states in deep inelastic scattering constitute ~ 25% of the inclusive cross-section at small x as measured at HERA. These data can reveal important information on the charm and gluon structure of the nucleon if they are interpreted in a consistent perturbative QCD framework which is valid over the entire energy range from threshold to the high energy limit. We describe in detail how this can be carried out order-by-order in PQCD in the generalized MSbar formalism of Collins (generally known as the ACOT approach), and demonstrate the inherent smooth transition from the 3-flavor to the 4-flavor scheme in a complete order αs calculation, using a Monte Carlo implementation of this formalism. This calculation is accurate to the same order as the conventional NLO F2 calculation in the limit Q/mc >> 1. It includes the resummed large logarithm contributions of the 3-flavor scheme (generally known in this context as the fixed-flavor-number or FFN scheme) to all orders of αsln (mc2/Q2). For the inclusive structure function, comparison with recent HERA data and the existing FFN calculation reveals that the relatively simple order-αs (NLO) 4-flavor (mc≠0) calculation can, in practice, be extended to rather low energy scales, yielding good agreement with data over the full measured Q2 range. The Monte Carlo implementation also allows the calculation of differential distributions with relevant kinematic cuts. Comparisons with available HERA data show qualitative agreement; however, they also indicate the need to extend the calculation to the next order to obtain better description of the differential distributions.
Biotechnology. The way ahead

The future for biotechnology looks very bright. Opportunities are increasing, largely because of advances in genetics and in computer-aided automation. In the past many biotechnology opportunities have arisen out of crisis-oriented problems. For example, acetone/butanol fermentations were developed to solve a need for acetone to manufacture cordite during World War I and penicillin fermentations evolved because of the need to develop antibiotics to prevent wound infections in World War II. It is felt that future opportunities will emerge largely from similar crises. These probably will involve chemical feedstock supply, alternative forms of energy, applications of genetics, health care and delivery problems, environmental concerns and computeraided automation.
Tagging of isobars using energy loss and time-of-flight measurements

Abstract The technique for tagging isobars in a mixed beam using differences in energy lost in an absorber by different isobars has been tested. As expected, isobar separation does improve by allowing more energy loss (thicker absorbers), but such gains could be realized only after achieving good absorber homogeneity. For heavy ions accelerated to low and moderate energies ( MeV / A ) , we found that when homogenous absorbers are used, the largest impediment to achieving good isobar separation rests with uncertainties in energy caused by straggling in the absorber. Measurements of beam energy loss and energy spread were shown to come close to predicted values when accounting for both collisional and charge-exchange contributions to the calculated energy straggling. Reliable prediction of energy straggling then allowed us to study the efficacy of this method for isobar separation when applied to different mass ranges and beam energies. Time-of-flight was used to measure energy loss since this method allows handling of counting rates in excess of 1 MHz and the demands on timing detector resolution and length of flight path were moderate for all cases under study here. Partial separation in a most difficult case, an analyzed beam of A=132 isobars at energies near 3 MeV / A has been demonstrated. The time-of-flight information can be added to the data stream for events of interest, as an additional parameter (tag) to the online data stream. Such event-by-event tagging enables one to study the effect of difference in isobaric mixture in the beam on the reaction outcome even when isobar separation is not complete.
A type system for object initialization in the Java bytecode language

In the standard Java implementation, a Java language program is compiled to Java bytecode. This bytecode may be sent across the network to another site, where it is then executed by the Java Virtual Machine. Since bytecode may be written by hand, or corrupted during network transmission, the Java Virtual Machine contains a bytecode verifier that performs a number of consistency checks before code is run. These checks include type correctness and, as illus-trated by previous attacks on the Java Virtual Machine, are critical for system security. In order to analyze existing bytecode verifiers and to understand the properties that should be verified, we develop a precise specification of statically correct Java bytecode, in the form of a type system. Our focus in this article is a subset of the bytecode language dealing with object creation and initialization. For this subset, we prove, that, for every Java bytecode program that satisfies our typing constraints, every object is initialized before it is used. The type system is easily combined with a previous system developed by Stata and Abadi for bytecode subroutines. Our analysis of subroutines and object initialization reveals a previously unpub-lished bug in the Sun JDK bytecode verifier.
Enol ether–olefin ring closing metathesis using the Grubbs ruthenium imidazole catalyst

Abstract This letter reports our successful use of the Grubbs ruthenium imidazole alkylidene catalyst in enol ether–olefin ring closing metathesis reactions.
The Cyclic Lot Scheduling Problem with Sequence-Dependent Setups

In this paper, we formulate the cyclic lot scheduling problem on a single facility with sequence-dependent setup costs and times and provide a heuristic solution procedure. A Lagrangian relaxation of the formulation leads to a partial separation of the embedded lot sizing and traveling salesman problems. The relaxation results in a new combinatorial problem related to the minimum spanning tree problem. The information about frequency of production, gained from the solution to this relaxation, is used to find heuristic solutions for the entire problem. Computational work on randomly generated problems shows that the problem becomes more difficult as the diversity in the sequence-dependent parameters increases.
FACTORS AFFECTING VEHICLE OCCUPANCY MEASUREMENT

Factors affecting vehicle occupancy measurement were examined with the aim of improving state and local vehicle occupancy monitoring programs. A comparison was conducted of five data sets looking at the effects on average vehicle occupancy (AVO) of time of day, day of week, road types, HOV lanes, locational differences, and traffic volume. It was found that AVO was higher in the afternoons, on Saturdays, and on HOV lanes. Inconsistent differences were found for the other variables, though there were considerable locational variations. Current vehicle occupancy monitoring programs do not generally take these factors into account and, most likely, produce biased estimates of AVO. Suggestions are made for using these factors in sample designs to represent regional and corridor-level vehicle occupancy levels.
A note on lattices in semi-stable representations

Let p be a prime, K a finite extension over \({{\mathbb Q}_p}\) and \({G = {\rm Gal}(\overline K /K)}\) . We extend Kisin’s theory on \({\varphi}\) -modules of finite E(u)-height to give a new classification of G-stable \({{\mathbb Z}1_p}\) -lattices in semi-stable representations.
Ceramic Dusting Corrosion of Yttria‐Stabilized Zirconia in Ultra High Temperature Reverse‐Flow Pyrolysis Reactors

A reverse-flow reactor enables the pyrolysis of hydrocarbons, at temperatures ranging from 1500°C to 2000°C, to high-value petrochemical products through acetylene intermediate. Materials in the hottest regions of the reactor, exposed to such extreme temperatures, are subject to oxidative cycling over a period of several seconds between a regeneration (heat addition) step that is mildly oxidizing and a pyrolysis (cracking) step that is strongly reducing, accompanied by high carbon activity. Experimental results obtained from single crystal and polycrystalline yttria-stabilized zirconia (YSZ) ceramics of different porosities show that the pyrolysis reaction triggers the carburization of YSZ by diffusion of carbon through the lattice, the grain boundaries, and the pores. Subsequently graphite deposition occurs on the carburized surface. During the regeneration step, some of the graphite and (oxy)carbide are reoxidized. Corrosion advances in subsequent cycles by a repetition of oxide-carbide interconversion, carbon precipitation, and reoxidation steps. Since degradation involves the breakup of the bulk ceramic structure into powder or “dust” and is reminiscent of metal dusting corrosion observed in metallic materials in carbon-supersaturated environments, we name this corrosion “ceramic dusting.” Details of the corrosion mechanism and the steps leading to such degradation are discussed.
Thoracic surgery workforce: report of STS/AATS Thoracic Surgery Practice and Access Task Force--snapshot 2010.

Background The Society of Thoracic Surgeons (STS) and the American Association for Thoracic Surgery (AATS) have intermittently surveyed their combined membership. These manpower surveys have provided snapshots of thoracic surgery, documenting practice changes over time. At this critical time in US health care reform the physician workforce is of critical importance. This survey updates the data obtained from the 2000 and 2005 surveys. Methods The survey instrument was updated from the 2005 survey. It was received by 5265 surgeon members of the STS/AATS during November and December 2009. There was a superb 50% return rate. The data were entered into a comprehensive database. Perception Solutions, Inc, independently performed the analysis. Results The median age of the active US thoracic surgeons is 52.9 years. Women comprise 3.4% of adult cardiac, 5.2% of congenital heart, and 7.9% of general thoracic surgeons. The decision to pursue a career in thoracic surgery was made before or in medical school by 45.3% of surgeons. The majority of survey respondents had a mean of 8.7 years of residency training after medical school graduation. The cumulative average educational debt was $56,000. Overall career satisfaction was 46% (very or extremely satisfied). Database participation was 84%. Operative volume over the past 12 months decreased for 30% of surgeons. Malpractice premiums have steadily increased over the past 5 years from $55,947 to $59,673. The number of additional years the currently active US cardiothoracic surgeon plans to practice is 12.6 years. Therefore, the projected retirement age of the thoracic surgery workforce will be 65. This is consistent among all surgeons: adult cardiac, 66 years; congenital heart, 65 years; and general thoracic, 67 years. Conclusions These data give a clear profile of the specialty at this time. The major challenges remain length of training and educational debt of the thoracic surgeon. Case volume, scope of practice, malpractice costs, and career satisfaction remain major elements to provide a positive environment to recruit new surgeons in to the specialty. The resident pool has contracted while the workforce ages and retirement looms. Significant shortages may develop as the US population ages in the environment of health care reform.
Activation and deactivation mechanisms for thin-film iron-titanium hydrides

Abstract FeTi is an alloy capable of reversible hydrogen storage at reasonable temperatures and pressures; however, it requires an initial activation procedure and experiences losses in sorption capacity after a number of charge-discharge cycles. Previous investigations are unclear as to the mechanism involved so that a detailed investigation was warranted. Backscatter conversion electron Mossbauer spectroscopy (CEMS), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) were used to probe the entire 10 nm, the top 2 nm and the top monolayer respectively of FeTi thin films after fabrication and various annealing, reduction and oxidation treatments. Data from these analyses support an initial ultrahigh-vacuum activation mechanism whereby iron oxides present on the surface are reduced by metallic titanium species in underlying FeTi layers to produce TiO2 and metallic iron domains. Metallic iron domains are exposed to the gas phase and are capable of dissociating molecular hydrogen. The mechanism responsible for the gradual loss in sorption capacity (i.e. cyclic deactivation) occurs when FeTi decomposes into metallic iron and TiO2 by reaction of titanium with ppm levels of O 2 H 2 O impurities in the H2 charging gas. Each of these products is relatively inactive toward reversible hydrogen storage in comparison with FeTi and they gradually accumulate over a number of charge-discharge cycles. Both initial activation and cyclic deactivation involve decomposition of FeTi in the surface region. Surface coatings may be helpful in eliminating the above noted phenomena.
Identification of brief pauses in the fluent speech of stutterers and nonstutterers.

Research has indicated that the fluent speech of stutterers is different from normal speech. A previous experiment suggested that a part of the difference between the fluent speech of normals and s...
Characterizations of orthonormal scale functions: A probabilistic approach

The construction of a multiresolution analysis starts with the specification of a scale function. The Fourier transform of this function is defined by an infinite product. The convergence of this product is usually discussed in the context of L2(R).Here, we treat the convergence problem by viewing the partial products as probabilities, converging weakly to a probability defined on an appropriate sequence space. We obtain a sufficient condition for this convergence, which is also necessary in the case where the scale function is continuous. These results extend and clarify those of Cohen [2] and Hernandez et al. [4]. The method also applies to more general dilation schemes that commute with translations byZd.
Traffic-responsive signal timing for system-wide traffic control

Abstract A long-standing problem in traffic engineering is to optimize the flow of vehicles through a given road network. Improving the timing of the traffic signals at intersections in the network is generally the most powerful and cost-effective means of achieving this goal. However, because of the many complex aspects of a traffic system—human behavioral considerations, vehicle flow interactions within the network, weather effects, traffic accidents, long-term (e.g. seasonal) variation, etc.—it has been notoriously difficult to determine the optimal signal timing. This is especially the case on a system-wide (multiple intersection) basis. Much of this difficulty has stemmed from the need to build extremely complex models of the traffic dynamics as a component of the control strategy. This paper presents a fundamentally different approach for optimal signal timing that eliminates the need for such complex models. The approach is based on a neural network (or other function approximator) serving as the basis for the control law, with the weight estimation occurring in closed-loop mode via the simultaneous perturbation stochastic approximation (SPSA) algorithm. The neural network function uses current traffic information to solve the current (instantaneous) traffic problem on a system-wide basis through an optimal signal timing strategy. The approach is illustrated by a realistic simulation of a nine-intersection network within the central business district of Manhattan, New York.
Syntheses and antifungal activities of novel 3-amido bearing pseudomycin analogues.

As a result of our core SAR effort, we discovered a large number of 3-amido pseudomycin B (PSB) analogues (e.g., 4e LY448212 and 5b LY448731) that retain good in vitro and in vivo (IP) activities against Candida and Cryptococcus without inherent tail vein irritation. Several dimethylamino termini bearing 3-amides (e.g., 5b) also exhibited improved potency against Aspergillus in vitro. When evaluated in a two-week rat toxicology study, it was found that all animals receiving 4e (up to 75 mg/kg) were found to be normal. On the basis of these observations, we are convinced that it is possible to broaden the antifungal spectrum and improve the safety profile of pseudomycin analogues at the same time.
Alone at sea: Chile's presencial ocean policy

Chile has long been at the forefront of international efforts to extend the ocean jurisdiction of coastal state. Its 1947 unilateral declaration of a 200-mile fisher/whaling zone eventually led to the internationally recognised concept of an Exclusive Economic Zone (EEZ) now contained in the 1982 Law of the Sea Convention. Chile is now promoting a new concept, the Presencial Sea. This would give coastal states special interests in the high seas adjacent to EEZs, and the right to take certain unilateral actions in respect of these interests. The specifics of such a concept are still in a state of development, but Chile's own claim, contained in a 1991 national law, would represent a 500% increase over the area covered by the country's existing EEZ. Justification of the need for the concept was in part based on problems with straddling fisheries, but the 1995 UN Straddling Stocks Agreement now provides an answer to some of those issues. Despite Chile's former success in promoting the recognition of EEZs, the concept of a Presencial Sea would in practice create chaos rather than stability in international law, and would result in the unravelling rather than the evolution of ocean governance.
Longevity bias in cost‐effectiveness analysis

We use a simple lifetime utility maximization model to study the problem of medical resource allocation. This model leads to a welfare specification with a QALY (quality-adjusted life-year) component that captures an individual's preferences over both life expectancy and health status. The goal of medical cost-effectiveness analysis (CEA) is characterized as maximizing the QALY measure for a given total medical expenditure. We show that the CEA with such a goal has a longevity bias: the CEA-based division of a given total medical expenditure between extending life and improving health gives the former a larger share than is called for by welfare maximization. Copyright © 2007 John Wiley & Sons, Ltd.
Women’s Earnings Before and After Marital Dissolution: Evidence from Longitudinal Earnings Records Matched to Survey Data

This paper investigates the change in women’s earnings following marital dissolution from a longitudinal approach. Using unique data that matches the Survey of Income and Program Participation (SIPP) with Social Security longitudinal earnings records, we examine marital dissolution events occurring between 1985 and 2003. Results show significant increases in women’s labor market involvement and earnings following marital dissolutions over the past two decades. We find greater labor force involvement prior to the dissolution event among more recent divorcees; however, among those already in the labor force, the pattern of change in earnings associated with divorce has changed little over the examined period. Human capital and family characteristics were associated with the change in earnings after marital dissolution.
Collisional radiative recombination in high‐pressure noble gas mixtures

Rate coefficients are calculated for neutral‐assisted collisional radiative recombination in dense, weakly ionized rare‐gas mixtures using the quasiequilibrium model developed by Bates. It is shown that the recombination rate can be significantly altered by the presence of a buffer gas. In particular, the presence of helium can enhance the collisional radiative recombination rate coefficient of heavy rare gases by a factor of 5.
Topology of the causal boundary for standard static spacetimes

The topology of the causal boundary for standard static spacetimes—spacetimes time-invariantly conformal to a metric product of the Lorentz line and a Riemannian manifold—is studied in depth. As this is given in terms of a set of real-valued functions on the Riemannian factor, one could use a function-space topology, but physical reasons recommend a chronological topology instead. The function-space topology has a simple product structure, while the chronological topology might not. This paper examines when the chronological topology coincides with the function-space topology and when it has a simple product structure. A class of standard static spacetimes is examined, all of which yield a simple product structure for the causal boundary; the conformal class of these spacetimes includes classical spacetimes such as external Schwarzschild or Reissner–Nordstrom.
The importance of collaboration in comparative effectiveness research

Collaboration has been viewed as crucial to the production of the type of comparative effectiveness research (CER) needed to inform real-world decisions by patients, providers and health systems.
Braneless black holes

It is known that the naive version of D-brane theory is inadequate to explain the black hole entropy in the limit in which the Schwarzschild radius becomes larger than all compactification radii. We present evidence that a more consistent description can be given in terms of strings with rescaled tensions. We show that the rescaling can be interpreted as a redshift of the tension of a fundamental string in the gravitational field of the black hole. An interesting connection is found between the string level number and the Rindler energy. Using this connection, we reproduce the entropies of Schwarzschild black holes in arbitrary dimensions in terms of the entropy of a single string at the Hagedorn temperature.
Simulated impacts of irrigation on the atmospheric circulation over Asia

[1] We find that irrigation significantly affects Asian summer climate, according to model simulations using the Community Atmosphere Model (CAM3.0) coupled to the Community Land Model (CLM3.5). Irrigation over the major river basins in the Middle East and central Asia causes a decrease in sensible heat fluxes and an increase in latent heat fluxes in boreal summer. These changes in heat fluxes lead to a cooling of both the surface and the lower troposphere over the irrigated regions. This atmospheric cooling, in turn, results in a cooling of the layer-averaged temperature (thickness temperature) in the troposphere. The irrigation-induced cooling in the troposphere, therefore, significantly decreases the tropospheric geopotential height over the irrigated regions. Lower height in the upper troposphere alters the upper-level atmospheric circulation over the irrigated and surrounding regions in Asia. Cyclonic differences of atmospheric circulation are simulated around negative differences of height and positive differences of vorticity between the irrigated and control runs, and they result in a weakening of the upper-level anticyclonic circulation over the tropical to midlatitude African-Asian regions. These changes in atmospheric circulation lead to a weakening of the strong upper-level westerly jet (Asian jet) over eastern Europe, the Middle East, and central Asia in 40°N ∼ 55°N. The irrigation impacts on the atmospheric circulation and Asian jet in boreal summer are supported by a comparison with observations.
Secondary Chern-Euler forms and the law of vector fields

The Law of Vector Fields is a term coined by Gottlieb for a relative Poincare-Hopf theorem. It was first proved by Morse (Mor29) and expresses the Euler characteristic of a manifold with boundary in terms of the indices of a generic vector field and the inner part of its tangential projection on the boundary. We give two elementary differential-geometric proofs of this topological theorem, in which secondary Chern-Euler forms (Che44) naturally play an essential role. In the first proof, the main point is to construct a chain away from some singularities. The second proof employs a study of the secondary Chern-Euler form on the boundary, which may be of independent interest. More precisely, we show by explicitly constructing a primitive that, away from the outward and inward unit normal vectors, the secondary Chern- Euler form is exact up to a pullback form. In either case, Stokes' theorem is used to complete the proof.
The welfare gains from pricing road congestion using automatic vehicle identification and on-vehicle meters

It is a widely accepted proposition that there is a general underpricing of auto travel in U.S. cities. Auto travel imposes a congestion externality with an efficient peak period level estimated at lo-23t per mile on urban freeways (Small 1121). 2* 3 But, for most urban auto travel, tolls consist almost entirely of the gasoline excise tax. At a fuel economy of 15 miles per gallon, the auto toll implied by the current high gas tax in the United States of 25e per gallon is only 1.7e per mile. This is much too low for most peak period travel and even underprices some off-peak travel. The purpose of this study is to estimate the welfare gains which are possible under different regimes for imposing higher auto tolls in urban areas. The three regimes studied are associated with a higher gas tax and systems called automatic vehicle identification and on-vehicle metering. The framework for the study is a model of a city whose shape is that of a wedge or pie-slice of a circle. The model’s features include:
EMITTANCE LIMITATION OF A CONDITIONED BEAM IN A STRONG FOCUSING FEL UNDULATOR

Various methods have been proposed to condition an electron beam in order to reduce its emittance effect and to improve the short-wavelength free electron laser (FEL) performance. In this paper, we show that beam conditioning does not result in a complete elimination of the emittance effect in an alternating-gradient focusing FEL undulator. Using a one-dimensional model and a three-dimensional simulation code, we derive a criteria for the emittance limitation of a perfectly conditioned beam that depends on the focusing structure.
Monolithically integrated low-power phototransceiver incorporating microcavity LEDs and multiquantum-well phototransistors

A low power GaAs-based monolithically integrated phototransceiver, consisting of a high gain phototransistor and a microcavity light-emitting diode, is demonstrated. The input and output wavelengths are 0.85 and 0.98 /spl mu/m, respectively. The phototransceiver exhibits an optical gain of 7 dB and power dissipation of 400 /spl mu/W for an input power of 1.5 /spl mu/W. The small signal modulation bandwidth is 80 MHz.
Modularity in the motion system: Independent oculomotor and perceptual processing of brief moving stimuli

In addition to motion perception per se, we utilize motion information for a wide range of brain functions. These varied functions place different demands on the visual system, and therefore a stimulus that provides useful information for one function may be inadequate for another. For example, the direction of motion of large high-contrast stimuli is difficult to discriminate perceptually, but other studies have shown that such stimuli are highly effective at eliciting directional oculomotor responses such as the ocular following response (OFR). Here, we investigated the degree of independence between perceptual and oculomotor processing by determining whether perceptually suppressed moving stimuli can nonetheless evoke reliable eye movements. We measured reflexively evoked tracking eye movements while observers discriminated the motion direction of large high-contrast stimuli. To quantify the discrimination ability of the oculomotor system, we used signal detection theory to generate associated oculometric functions. The results showed that oculomotor sensitivity to motion direction is not predicted by perceptual sensitivity to the same stimuli. In fact, in several cases oculomotor responses were more reliable than perceptual responses. Moreover, a trial-by-trial analysis indicated that, for stimuli tested in this study, oculomotor processing was statistically independent from perceptual processing. Evidently, perceptual and oculomotor responses reflect the activity of independent dissociable mechanisms despite operating on the same input. While results of this kind have traditionally been interpreted in the framework of perception versus action, we propose that these differences reflect a more general principle of modularity.
Inheritances and the Distribution of Wealth Or Whatever Happened to the Great Inheritance Boom

Using data from the Survey of Consumer Finances (SCF), we found that on average over the period from 1989 to 2007, about one fifth of American households at a given point of time reported a wealth transfer and these accounted for quite a sizeable figure, about a quarter of their net worth. Over the lifetime, about 30 percent of households could expect to receive a wealth transfer and these would account for close to 40 % of their net worth near time of death. However, there is little evidence of an inheritance “boom.” In fact, from 1989 to 2007, the share of households reporting a wealth transfer fell by 2.5 percentage points, a time trend statistically significant at the one percent level. The average value of inheritances received among all households did increase but at a slow pace, by 10 %; the time trend is not statistically significant. Wealth transfers as a proportion of current net worth fell sharply over this period, from 29 to 19 %, though the time trend once again is not statistically significant. We also found that inheritances and other wealth transfers tend to be equalizing in terms of the distribution of household wealth, though a number of caveats apply to this result.
On the design of robust controllers for arbitrary uncertainty structures

The focal point of this paper is the design of robust controllers for linear time-invariant uncertain systems. Given bounds on performance (defined by a convex performance evaluator) the algorithm converges to a controller that robustly satisfies the specifications. The procedure introduced has its basis on stochastic gradient algorithms and it is proven that the probability of performance violation tends to zero with probability one. Moreover, this algorithm can be applied to any uncertain plant, independently of the uncertainty structure. As an example of application of this new approach, we demonstrate its usefulness in the design of robust H/sub 2/ controllers.
Abruptly autofocusing vortex beams

We generate abruptly autofocusing beams that can produce vortices at the focus spot. We give equations for controlling the focal distance and numerical aperture. Experimental results are presented.
The Uses of Argument in Mathematics

Stephen Toulmin once observed that ‘it has never been customary for philosophers to pay much attention to the rhetoric of mathematical debate’ [Toulmin et al., 1979, An Introduction to Reasoning, Macmillan, London, p. 89]. Might the application of Toulmin’s layout of arguments to mathematics remedy this oversight? Toulmin’s critics fault the layout as requiring so much abstraction as to permit incompatible reconstructions. Mathematical proofs may indeed be represented by fundamentally distinct layouts. However, cases of genuine conflict characteristically reflect an underlying disagreement about the nature of the proof in question.
The effect of second-phase oxides on the catalytic properties of dispersed metals: Cobalt supported on 12% WO3/Al2O3

Abstract The differences in the amphoteric properties Of WO3 and Al2O3 were exploited and cobalt precursors were selectively mounted on the tungsten oxide phase of a 12% WO3/Al2O3 composite. Temperature-programmed reduction (TPRd), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and catalyst performance testing using H2/CO methanation as a test reaction revealed that this composite-supported catalyst's properties were significantly different from cobalt supported on alumina. Cobalt crystallites as well as a CoAl2O4 type of surface species are formed on the Al2O3 support. The presence of WO3 as a second-phase oxide offers the possibility for a greater number of surface compounds to be formed on the composite. Specifically, cobalt-tungsten interaction species are formed. We provide evidence that strongly suggests the active catalytic center in the conversion of H2 and CO to methane is a (cobalt-tungsten) interaction species. These active centers. are present on CO/WO3, Co/12% WO3/Al2O3, and a commercial cobalt/tungsten oxide compound. A portion of the cobalt: in these active centers is not reduced to the metallic state.
Mining frequent graph patterns with differential privacy

Discovering frequent graph patterns in a graph database offers valuable information in a variety of applications. However, if the graph dataset contains sensitive data of individuals such as mobile phone-call graphs and web-click graphs, releasing discovered frequent patterns may present a threat to the privacy of individuals. Differential privacy has recently emerged as the de facto standard for private data analysis due to its provable privacy guarantee. In this paper we propose the first differentially private algorithm for mining frequent graph patterns. We first show that previous techniques on differentially private discovery of frequent itemsets cannot apply in mining frequent graph patterns due to the inherent complexity of handling structural information in graphs. We then address this challenge by proposing a Markov Chain Monte Carlo (MCMC) sampling based algorithm. Unlike previous work on frequent itemset mining, our techniques do not rely on the output of a non-private mining algorithm. Instead, we observe that both frequent graph pattern mining and the guarantee of differential privacy can be unified into an MCMC sampling framework. In addition, we establish the privacy and utility guarantee of our algorithm and propose an efficient neighboring pattern counting technique as well. Experimental results show that the proposed algorithm is able to output frequent patterns with good precision.
Local Floer homology and infinitely many simple Reeb orbits

Let Q be a Riemannian manifold such that the Betti numbers of its free loop space with respect to some coefficient field are unbounded. We show that every contact form on its unit cotangent bundle supporting the natural contact structure has infinitely many simple Reeb orbits. This is an extension of a theorem by Gromoll and Meyer. We also show that if a compact manifold admits a Stein fillable contact structure then there is a possibly different such structure which also has infinitely many simple Reeb orbits for every supporting contact form. We use local Floer homology along with symplectic homology to prove these facts.