cssi/SciSciGPT-SciSciNet huggingface dataset:
Analysis of cracked aluminum plates repaired with bonded composite patches

Bonded composite repair has been recognized as an efficient and economical method to extend the service life of cracked aluminum components. An accurate tool for investigating the stress intensity factor in the cracked aluminum structure after repair is needed. The use of three-dimensional finite elements is computationally expensive. A simple analysis method using Mindlin plate theory is presented. Specifically, the aluminum plate and composite patch are modeled separately by the Mindlin plate finite element, whereas the adhesive layer is modeled with effective springs connecting the patch and aluminum plate. Constraint equations are used to enforce compatibility of the patch-adhesive and adhesive-aluminum plate interfaces. Comparison of the present stress intensity factors for the aluminum crack with a plane boundary element analysis and a three-dimensional finite element analysis are made. A procedure for calculating the strain energy release rate along the debond front at the aluminum-adhesive interface is proposed.
Carbon sequestration and permit trading on the competitive fringe

Abstract This paper makes two contributions to the carbon-sequestration policy literature. First and foremost, we develop a theoretical framework in which sequestration and permit-trading markets are analyzed jointly in the context of a competitive fringe model. Our framework formalizes the linkage between regulatory policy changes (as they manifest themselves in the permit market) and subsequent equilibrium allocations in the sequestration market. Second, we perform a numerical analysis demonstrating the role market structure, or market power, might play in the determination of the equilibrium sequestration allocation and carbon price. Both our analytical and numerical results demonstrate the importance of incorporating into empirical supply-side models demand-side information that is reflective of an underlying market structure.
Quality uncertainty and time inconsistency in a durable good market

In a durable good monopoly where consumers cannot observe quality prior to purchase and product improvement occurs exogenously over time, I show that uncertainty in quality may resolve the time inconsistency problem (even for low levels of product improvement). Higher dispersion in quality creates greater demand for future product by increasing the incentive of buyers with inferior quality realizations to repeat purchase and this, in turn, reduces the incentive of the seller to cut future price. For various levels of product improvement, I characterize the range of quality uncertainty for which the market equilibrium is identical to one where the monopolist can credibly precommit to future prices. I also show that the presence of quality uncertainty can lead to no trading in the primary good market. Further, in contrast to the literature on the Coase conjecture, inability to precommit to future prices can reduce social welfare as a result of the market closure.
Total Synthesis of Apoptolidin: Completion of the Synthesis and Analogue Synthesis and Evaluation

The total synthesis of apoptolidin (1) is reported together with the design, synthesis, and biological evaluation of a number of analogues. The assembly of key fragments 6 and 7 to vinyl iodide 3 via dithiane coupling technology was supplemented by a second generation route to this advanced intermediate involving a Horner-Wadsworth-Emmons coupling of fragments 22 and 25. The final stages of the synthesis featured a Stille coupling between vinyl iodide 3 and vinylstannane 2, a Yamaguchi lactonization, a number of glycosidations, and final deprotection. The developed synthetic technology was applied to the construction of several analogues including 74, 75, and 77 which exhibit significant bioactivity against tumor cells.
Review of Recent Placebo-Controlled Trials Utilizing Phytotherapeutic Agents for Treatment of BPH

BACKGROUND In order to assess the efficacy of phytotherapeutic agents for the treatment of benign prostatic hyperplasia (BPH), a review of recently published double-blind placebo-controlled trials was undertaken. METHODS Only those studies reviewed by the Other Medical Therapies Committee of the Fourth International Consultation on BPH were included. RESULTS These studies suggest a possible benefit for the use of phytotherapeutic preparations in the treatment of BPH. CONCLUSIONS These studies need to be confirmed in larger long-term placebo-controlled studies in order to ascertain the true efficacy of these agents. Prostate 37:187–193, 1998. © 1998 Wiley-Liss, Inc.
Noise Considerations in Millimeter-Wave Spectrometers

An improved version of a microwave spectrometer operating in the vicinity of 70 GHz is described. The spectrometer, which incorporates a Fabry-Perot resonator and superhet-erodyne detection for high sensitivity is designed for the detection of gaseous pollutants and other atmospheric constituents. The instrument is capable of detecting polar molecules with absorption coefficients as small as 2 x 10-9cm-1. For sulphur dioxide diluted in air, this sensitivity corresponds to a detection limit of 1.2 ppm without preconcentration and with a time constant of 1 second. Measurements and analysis of the noise contributions limiting the sensitivity are presented.
T-duality in arbitrary string backgrounds

Abstract T-duality is a poorly understood symmetry of the space-time fields of string theory that interchanges long and short distances. It is best understood in the context of toroidal compactification where, loosely speaking, radii of the torus are inverted. Even in this case, however, conventional techniques permit an understanding of the transformations only in the case where the metric on the torus is endowed with Abelian Killing symmetries. Attempting to apply these techniques to a general metric appears to yield a non-local world-sheet theory that would defy interpretation in terms of space-time fields. However, there is now available a simple but powerful general approach to understanding the symmetry transformations of string theory, which are generated by certain similarity transformations of the stress tensors of the associated conformal field theories. We apply this method to the particular case of T-duality and (i) rederive the known transformations, (ii) prove that the problem of non-locality is illusory, (iii) give an explicit example of the transformation of a metric that lacks Killing symmetries and (iv) derive a simple transformation rule for arbitrary string fields on tori.
Metal-oxide interfaces: where the action is.

Heterogeneous catalyst systems comprising metals supported on oxides are widespread. Evidence now suggests that it is the interfacial regions that are most catalytically active, and this has been exploited to create a tandem nanocatalyst system.
Supernormal Vector Configurations

A configuration of lattice vectors is supernormal if it contains a Hilbert basis for every pointed cone spanned by a subset. We study such configurations from various perspectives, including triangulations, integer programming and Grobner bases. Our main result is a bijection between virtual chambers of the configuration and virtual initial ideals of the associated binomial ideal.
Professional stock analysts' recommendations: Implications for individual investors

Abstract Conclusions regarding analyst performance often depend on the evaluation technique employed. Using a wide variety of techniques, we find that although there is some evidence that analysts do have the ability to identify undervalued and overvalued securities, individual investors generally experience inferior portfolio performance by following analyst recommendations published in the “Market Highlights” section of USA Today (even before transaction costs are included). As a result, individual investors should view studies that purport to show superior performance with skepticism. This statement is particularly true when the assertions are based on stock index comparisons.
Speedups of deterministic machines by synchronous parallel machines

Abstract This paper presents the new speedups DTIME(T)⊆ATIME(T/log T) and DTIME(T)⊆ PRAM-time(√T). These improve the results of Hopcroft, Paul, and Valiant (J. Assoc. Comput. Mach. 24 (1977), 332–337) that DTIME(T)⊆DSPACE(T/logT), and of Paul and Reichuk (Acta Inform. 14 (1980), 391–403) that DTIME(T)⊆ATIME ( (T log log T) log T ) . the new approach unifies not only these two previous results, but also the result of Paterson and Valiant (Theoret. Comput. Sci. 2 (1976), 397–400) that Size(T)⊆Depth(O(T/log T)).
LMFBR safety testing needs and the conceptual design of a new safety research experiment facility

Abstract A substantial fraction of the US LMFBR safety program is devoted to in-pile testing. Recognition of this has led to continuing studies of the need for new facilities. Based on these studies, ANL is currently engaged in the conceptual design of a new safety testing facility. The need for and the conceptual design of this facility is presented. The study program for inpile tests considered the following questions: (1) What are the key safety issues that require in-pile testing to be resolved? (2) What types of in-pile experiments are needed to address the key safety issues? (3) What facility functional requirements (e.g. scale, energy requirements, power flatness, etc.) are necessary? (4) What reactor concepts will meet the experimental needs? These studies concluded that new facility capability would be required. This new capability would include testing fuel arrays up to full subassembly size (and possibly larger). A comprehensive screening and evaluation of test reactor concepts was performed to identify the generic types of reactors, and specific concepts within each type which could meet the experimental needs. Three generic types of reactors were studied. The first (designated class I) was defined as a system capable of generating shaped transients without the need for significant reactor heat removal during the test. An additional requirements that can be imposed on the test reactor is some limited form of heat removal during a test which would permit longer-term operation, particularly at lower power levels, in addition to shaped power transients. This type of facility was designated class II. A further extension of the previous types to provide long-term steady-state operation (for days or weeks) in addition to class I and class II capabilities was designated as a class III facility. Based on the studies, a mixed-spectrum class I facility was chosen to purpose through the conceptual design. The key safety issues requiring in-pile testing, the types of experiments to be performed, the facility selection process, and a description of the conceptual design of this facility and its performance characteristics are discussed.
Fluid flow into vertical fractures from a point source

Flow into a fracture from a point source recently has been the focus of attention in the petroleum industry. The suggestion has been made that, in this flow configuration, convection (gravity-driven flow) would dominate Stokes`-type settling for determining final proppant distribution. The theory is that when a dense fluid flows into a fracture filled with a less dense fluid from a point source, the density of the fluid will force it to the bottom of the fracture. This clearly happens when the two fluids have low viscosity. However, viscosity of both the fluid in the fracture and the displacing fluid and nonuniformities in the fracture influence displacement process significantly. Results presented in this study clearly show the effects of viscosity and fracture nonuniformity on the convective settling mechanism.
Experimental Observations of a Thoria Oxide-Ion Sensor in a Molten Salt System

A uranium oxide reduction process under development at Argonne National Laboratory utilizes a Li/LiCl-based system at 650 C. When UO{sub 2} is introduced to this system, the lithium metal reduces UO{sub 2} to metallic uranium and generates Li{sub 2}O. A ThO{sub 2} solid electrolyte was selected and tested as an oxide-ion sensor to monitor the concentration of Li{sub 2}O in the molten LiCl during the uranium reduction process. Experimental results indicated that a ThO{sub 2} probe doped with 7.5 wt % Y{sub 2}O{sub 3} was effective at real-time monitoring of the oxide ion resulting from incremental additions of Li{sub 2}O to the Li/LiCl-based system. The experimental results also indicated that the activity and activity coefficient of Li{sub 2}O in molten LiCl at 650 C are consistent with Raoult's law.
Optimal taxation and the stationarity of state tax rates

To minimize deadweight losses, tax rates should vary unpredictably so agents cannot rearrange their work and consumption habits. As a result, optimally set tax rates will be a nonstationary time series or, put differently, changes in the tax rate will be unpredictable. This paper identifies different fiscal policy environments under which groups of states operate and tests whether these commonalities explain the behavior of states' tax rate setting behavior. Results show that only states that must balance less than 50% of their budgets or have a supermajority rule optimally set tax rates.
Games for formal design and verification of reactive systems

Summary form only given. With recent advances in algorithms for state-space traversal and in techniques for automatic abstraction of source code, model checking has emerged as a key tool for analyzing and debugging software systems. This talk discusses the role of games in modeling and analysis of software systems. Games are useful in modeling open systems where the distinction among the choices controlled by different components is made explicit. We first describe the model checker Mocha that supports a game-based temporal logic for writing requirements, and its applications to analysis of multi-party security protocols. Then, we describe how to automatically extract dynamic interfaces for Java classes using predicate abstraction for extracting a Boolean model from a class file, and learning algorithms for constructing the most general strategy for invoking the methods of the model. We discuss an implementation in the tool JIST - Java Interface Synthesis Tool and demonstrate that the tool can construct interfaces, accurately and efficiently, for sample Java2SDK library' classes.
Anomalous Radio-Wave Scattering from Interstellar Plasma Structures

This paper considers scattering screens that have arbitrary spatial variations of scattering strength transverse to the line of sight, including screens that are spatially well confined, such as disks and filaments. We calculate the scattered image of a point source and the observed pulse shape of a scattered impulse. The consequences of screen confinement include (1) source image shapes that are determined by the physical extent of the screen rather than by the shapes of much smaller diffracting microirregularities (these include image elongations and orientations that are frequency dependent); (2) variation with frequency of angular broadening that is much weaker than the trademark ν-2 scaling law (for a cold, unmagnetized plasma), including frequency-independent cases; and (3) similar departure of the pulse-broadening time from the usually expected ν-4 scaling law. We briefly discuss applications that include scattering of pulses from the Crab pulsar by filaments in the Crab Nebula; image asymmetries from Galactic scattering of the sources Cyg X-3, Sgr A*, and NGC 6334B; and scattering of background active galactic nuclei by intervening galaxies. We also address the consequences for inferences about the shape of the wavenumber spectrum of electron density irregularities, which depend on scaling laws for the image size and the pulse broadening. Future low-frequency (<100 MHz) array observations will also be strongly affected by the Galactic structure of scattering material. Our formalism is derived in the context of radio scattering by plasma density fluctuations. It is also applicable to optical, UV, and X-ray scattering by grains in the interstellar medium.
Determining the H+ Region / PDR Equation of State in Star-forming Regions

The emission-line regions of starburst galaxies and active nuclei reveal a wealth of spectroscopic information. A unified picture of the relationship among ionized, atomic, and molecular gas makes it possible to better understand these observations. We performed a series of calculations designed to determine the equation of state—the relationship among density, temperature, and pressure—through emission-line diagnostic ratios that form in the H+ region and the photodissociation region (PDR). We consider a wide range of physical conditions in the H+ region. We connect the H+ region to the PDR by considering two constant pressure cases: one with no magnetic field and one in which the magnetic field overwhelms the thermal pressure. We show that diagnostic ratios can yield the equation of state for single H+ regions adjacent to single PDRs, with the results being more ambiguous when considering observations of entire galaxies. As a test, we apply our calculations to the Orion H+/PDR region behind the Trapezium. We find the ratio of thermal to magnetic pressure in the PDR to be ~1.2. If magnetic and turbulent energy are in equipartition, our results mean that the magnetic field is not the cause of the unexplained broadening in M42, but may significantly affect line broadening in the PDR. Since Orion is often used to understand physical processes in extragalactic environments, our calculations suggest that magnetic pressure should be considered in modeling such regions.
Low-cost attitude determination system and imager with embedded compression

The Space Astronomy Laboratory has built and flown a very- low-cost (approximately 50K) star tracker and digital imaging system with embedded compression. The star tracker is suitable for all rocket and spacecraft applications, and provides pitch, yaw, and roll updates at rates up to 10 Hz. The digital imaging subsystem uses a novel NASA-funded scheme of `progressive image transmission' in which the image is sent out over a very-low-bandwidth channel, such as a telemetry downlink, in such a way that it can be reconstructed `on the fly' and updated as more data arrive. Large (768 X 474) useful images can be obtained over a 4- kbit/s downlink in as little as 10 seconds. This device can act as an aspect camera, a deployment monitor, or a science imager in situations where low bandwidth is desired or high bandwidth is not available.
Nonabelian localization in equivariant K-theory and Riemann–Roch for quotients

Abstract We prove a localization formula in equivariant algebraic K -theory for an arbitrary complex algebraic group acting with finite stabilizer on a smooth algebraic space. This extends to nondiagonalizable groups the localization formulas of Nielsen [Diagonalizably linearized coherent sheaves, Bull. Soc. Math. France 102 (1974) 85–97] and Thomason [Une formule de Lefschetz en K -theorie equivariante algebrique, Duke Math. J. 68(3) (1992) 447–462]. As an application we give a Riemann–Roch formula for quotients of smooth algebraic spaces by proper group actions. This formula extends previous work of Toen [Theoremes de Riemann–Roch pour les champs de Deligne-Mumford, K -Theory 18(1) (1999) 33–76] and the authors [Riemann–Roch for quotients and Todd classes of simplicial toric varieties, Comm. Algebra 31 (2003) 3735–3752].
Chemical relaxation times in a hadron gas at finite temperature

The relaxation time of particle numbers in hot hadronic matter with vanishing baryon number are estimated using the ideal gas approximation and taking into account resonance decays and annihilation processes as the only sources of particle number fluctuations.Near the QCD critical temperature the longest relaxation times turn out to be of the order of 10 fm and grow roughly exponentially to become of the order of 10^3 fm at temperatures around 100 MeV.As a consequence of such long relaxation times, a clear departure from chemical equilibrium must be observed in the momentum distribution of secondary particles produced in high energy nuclear collisions.
Sunyaev–Zeldovich fluctuations from the first stars?

WMAP's detection of high electron-scattering optical depth τ e suggests substantial star formation at high redshift z∼ 17 ± 5. On the other hand, the recovered σ 8 ∼ 0.84 ± 0.04 argues against a cluster Sunyaev–Zeldovich (SZ) origin for the observed small-scale cosmic microwave background (CMB) fluctuation excess, which generally requires σ 8 ∼ 1.1. Here we consider the effects of high-redshift star formation on the CMB. We derive a fairly model-independent relation between τ e and the number of ionizing photons emitted per baryon N γ , and use this to calibrate the amount of high-redshift supernova activity. The resulting supernova remnants Compton cool against the CMB creating a Compton y distortion y∼ few × 10 −6 within observational bounds. However they also create small-scale SZ fluctuations, which could be comparable with SZ fluctuations from unresolved galaxy clusters. This raises the exciting possibility that we have already detected signatures of the first stars not just once, but twice, in the CMB.
Five dimensional SUSY field theories, non-trivial fixed points and string dynamics

Abstract We study (non-renormalizable) five dimensional supersymmetric field theories. The theories are parametrized by quark masses and a gauge coupling. We derive the metric on the Coulomb branch exactly. We use stringy considerations to learn about new non-trivial interacting field theories with exceptional global symmetry En (E8, E7, E6, E5 = Spin(10), E4 = SU (5), E3 = SU (3) × SU (2), E2 = SU (2) × U (1) and E(1 = SU (2)). Their Coulomb branch is R+ and their Higgs branch is isomorphic to the moduli space of En instantons. One of the relevant operators of these theories leads to a flow to SU (2) gauge theories with Nf = n − 1 flavors. In terms of these SU (2) IR theories this relevant parameter is the inverse gauge coupling constant. Other relevant operators (which become quark masses after flowing to the SU (2) theories) lead to flows between them. Upon further compactifications to four and three dimensions we find new fixed points with exceptional symmetries.
Compression-related properties of color spaces

In modern color imaging a variety of color spaces are used to represent an image. It has been well established in literature that the choice of color space has an impact on the achievable compression. The purpose of this research is to investigate compression related properties of various color spaces. We investigated what we considered to be the most popular color spaces used today, namely, RGB, YIQ, YUV, YCbCr, HSI, CMYK, XYZ and CIELab. The following properties of color spaces that influence compressibility have been studied: energy distribution among color planes, plane bandwidth, DCT energy compaction, and impact of gamma correction. We also compared the compressibility of low resolution images, which have been used for most of the compression results reported in literature, with high resolution images, which are becoming increasingly important for modern imaging applications. The findings of this research have been illustrated by comparing the actual JPEG compression results for YCbCr and CIELab spaces.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Combining mean reversion and momentum trading strategies in foreign exchange markets.

Abstract The literature on equity markets documents the existence of mean reversion and momentum phenomena. Researchers in foreign exchange markets find that foreign exchange rates also display behaviors akin to momentum and mean reversion. This paper implements a trading strategy combining mean reversion and momentum in foreign exchange markets. The strategy was originally designed for equity markets, but it also generates abnormal returns when applied to uncovered interest parity deviations for five countries. I find that the pattern for the positions thus created in the foreign exchange markets is qualitatively similar to that found in the equity markets. Quantitatively, this strategy performs better in foreign exchange markets than in equity markets. Also, it outperforms traditional foreign exchange trading strategies, such as carry trades and moving average rules.
Communication-free hyperplane partitioning of nested loops

Abstract This paper addresses the problem of partitioning the iterations of nested loops, and data arrays accessed by the loops. Hyperplane partitions of disjoint subsets of data arrays and loop iterations that result in the elimination of communication are sought. A characterization of necessary and sufficient conditions for communication-free hyperplane partitioning is provided.
TASSY: one approach to individualized test construction

During the past ten years universities and the computing industry have seen the development of a new mode of teaching called Computer Aided---or Assisted---Instruction (C.A.I.). This new field, emerged as an attempt to meet and deal with the growing criticism and frustration of students, employers, legislators, and faculties, which stemmed from our inability to prepare students adequately.
DNS of the thermal effects of laser energy deposition in isotropic turbulence

The interaction of a laser-induced plasma with isotropic turbulence is studied using numerical simulations. The simulations use air as the working fluid and assume local thermodynamic equilibrium. The numerical method is fully spectral and uses a shock-capturing scheme in a corrector step. A model problem involving the effect of energy deposition on an isolated vortex is studied as a first step towards plasma/turbulence interaction. Turbulent Reynolds number Reλ = 30 and fluctuation Mach numbers Mt = 0.001 and 0.3 are considered. A tear-drop-shaped shock wave is observed to propagate into the background, and progressively become spherical in time. The turbulence experiences strong compression due to the shock wave and strong expansion in the core. This behaviour is spatially inhomogeneous and non-stationary in time. Statistics are computed as functions of radial distance from the plasma axis and angular distance across the surface of the shock wave. For Mt = 0.001, the shock wave propagates on a much faster time scale compared to the turbulence evolution. At Mt of 0.3, the time scale of the shock wave is comparable to that of the background. For both cases the mean flow is classified into shock formation, shock propagation and subsequent collapse of the plasma core, and the effect of turbulence on each of these phases is studied in detail. The effect of mean vorticity production on the turbulent vorticity field is also discussed. Turbulent kinetic energy budgets are presented to explain the mechanism underlying the transfer of energy between the mean flow and background turbulence.
The impact of public basic research on industrial innovation: Evidence from the pharmaceutical industry

While most economists believe that public scientific research fuels industry innovation and economic growth, systematic evidence supporting this relationship is surprisingly limited. In a recent study, Acemoglu and Linn (2004) identified market size as a significant driver of drug innovation in the pharmaceutical industry, but they did not find any evidence supporting science-driven innovation from publicly funded research. This paper uses new data on biomedical research investments by the U.S. National Institutes of Health (NIH) to examine the contribution of public research to pharmaceutical innovation. The empirical analysis finds that both market size and NIH funded basic research have economically and statistically significant effects on the entry of new drugs with the contribution of public basic research coming in the earliest stage of pharmaceutical drug discovery. The analysis also finds a positive return to public investment in basic biomedical research.
Nickel-Catalyzed Direct Addition of Diorganozinc Reagents to Phthalimides: Selective Formation of Gamma-Hydroxylactams

The nickel-catalyzed addition of diorganozinc reagents to phthalimides proceeds with excellent selectivity to provide 3-substituted-3-hydroxyisoindolin-1-one products. These 3-hydroxy-γ-lactams are produced cleanly in high yield with numerous examples of imide substitution and a broad range of diorganozinc reagents that are prepared and utilized without purification.
The looping constant of Z d

The looping constanti¾?i¾?d is the expected number of neighbors of the origin that lie on the infinite loop-erased random walk in i¾?d. Poghosyan, Priezzhev, and Ruelle, and independently, Kenyon and Wilson, proved recently that i¾?i¾?2=54. We consider the infinite volume limits as Gi¾?i¾?d of three different statistics: 1 The expected length of the cycle in a uniform spanning unicycle of G; 2 The expected density of a uniform recurrent state of the abelian sandpile model on G; and 3 The ratio of the number of spanning unicycles of G to the number of rooted spanning trees of G. We show that all three limits are rational functions of the looping constant i¾?i¾?d. In the case of i¾?2, their respective values are 8, 178 and 18. © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 45, 1-13, 2014
Buckling of long compression-loaded anisotropic plates restrained against inplane lateral and shear deformations

Abstract An approach for synthesizing buckling results and behavior for thin balanced and unbalanced symmetric laminates that are subjected to uniform axial compression loads and elastically restrained against inplane expansion, contraction, and shear deformation is presented. This approach uses a nondimensional analysis for infinitely long, flexurally anisotropic plates (coupling between bending and twisting) that are subjected to combined mechanical loads and is based on nondimensional parameters. In addition, nondimensional loading parameters are derived that account for the effects of the elastic inplane deformation restraints, membrane orthotropy, and membrane anisotropy on the induced prebuckling stress state. The loading parameters are used to determine buckling coefficients that include the effects of flexural orthotropy and flexural anisotropy. Many results are presented, for some selected laminates, that are intended to facilitate a structural designer’s transition to the use of the generic buckling-design curves that are presented and discussed in the paper. Several buckling response curves are presented that provide physical insight into the behavior for combined loads, in addition to providing useful design data. An example is presented that demonstrates the use of the generic design curves, which are applicable to a wide range of laminate constructions. The analysis approach and generic results indicate the effects and characteristics of laminate orthotropy and anisotropy in a very general and unifying manner.
Changing composition of the global stratosphere.

The current understanding of stratospheric chemistry is reviewed with particular attention to the influence of human activity. Models are in good agreement with measurements for a variety of species in the mid-latitude stratosphere, with the possible exception of ozone (O3) at high altitude. Rates calculated for loss of O3 exceed rates for production by about 40 percent at 40 kilometers, indicating a possible but as yet unidentified source of high-altitude O3. The rapid loss of O3 beginning in the mid-1970s at low altitudes over Antarctica in the spring is due primarily to catalytic cycles involving halogen radicals. Reactions on surfaces of polar stratospheric clouds play an important role in regulating the abundance of these radicals. Similar effects could occur in northern polar regions and in cold regions of the tropics. It is argued that the Antarctic phenomenon is likely to persist: prompt drastic reduction in the emission of industrial halocarbons is required if the damage to stratospheric O3 is to be reversed.
The New Political Economy of Geographical Intelligence

A troubling new political economy of geographical intelligence has emerged in the United States over the last two decades. The contours of this new political economy are difficult to identify due to official policies keeping much relevant information secret. The U.S. intelligence community increasingly relies on private corporations, working as contractors, to undertake intelligence work, including geographical intelligence (formally known as GEOINT). In this article we first describe the geography intelligence “contracting nexus” consisting of tens of thousands of companies (including those in the geographical information systems and mapping sector), universities and nonprofits receiving Department of Defense and intelligence agency funding. Second, we discuss the “knowledge nexus” to conceptualize how geographical knowledge figures in current U.S. intelligence efforts, themselves part of the U.S. war on terror and counterinsurgency (COIN). To analyze the contracting nexus we compiled and examined extens...
A propellant-based technology for multiple-fracturing wellbores to enhance gas recovery: application and results in Devonian shale

A propellant based technology has been developed that permits control of borehole pressurization to obtain multiple radial fractures about the wellbore. The objective is to connect nonintersecting natural fractures in a reservoir to the wellbore and thereby stimulate increase production. Techniques are presented for specifying the pressure pulse required for producing multiple fractures and for choosing propellants to achieve the desired pressure pulse. The multiple fracturing technique was specifically developed for application in naturally fractured Devonian shale gas reservoirs. A stimulation experiment in a Devonian shale gas well successfully increased production from 6700 ft /sup 3//day to 22,000 ft/sup 3//day (190 m/sup 3//day to 623 m/sup 3//day). 16 references, 9 figures, 3 tables.
Decadal weakening of the shallow overturning circulation in the South Indian Ocean

[1] Satellite observations reveal a substantial weakening of the southeasterly trade wind over the South Indian Ocean during 1992–2000 and a resultant slowdown of the shallow meridional overturning circulation in this Ocean. The estimated rate of the slowdown of this circulation, 6.8 ± 1.4 × 106 m3/s over the 9-year period, is nearly 70% of the mean strength of this circulation. Such a change has important implications to upper-ocean heat content and decadal climate variability of the Indian Ocean, as well as to the ecosystem and air-sea exchange of CO2 in the region.
Low-Velocity Impact Response and Dynamic Characteristics of Glass-Resin Composites

This paper describes a test methodology used for characterizing different glass-resin composite systems with respect to their low-velocity impact response, dynamic modulus and inherent damping properties. Impact tests were conducted on SMC plaque samples in an instrumented impact test machine. A Dynamic Mechanical Analyzer was used for testing small rectangular samples in the fixed frequency mode of operation. An impulse-frequency response vibration technique was used for obtaining the dynamic modulus and loss factor of cantilever beam specimens at ambient conditions. The dynamic modulus, glass transition and damping peak intensities obtained from the DMA and the vibration techniques are correlated with the impact test data. The potential application for screening glass-resin formulations with respect to their impact performance is discussed.
Statistical models for the image restoration problem

Abstract Inversion of the image formation equation for its object is an unstable or “ill-conditioned” problem. Severe error propagation tends to result. This can be reduced, however, by building a priori knowledge about the object in the form of constraints into the restoring procedure. In turn, these constraints can be accomplished by modeling the object in a suitable, statistical way. This paper is a survey of statistical models that have led to restoration methods which overcome to various degrees the ill-conditioned nature of the problem.
The best approximation to C/sup 2/ functions and its error bounds using regular-center Gaussian networks

Gaussian neural networks are considered to approximate any C/sup 2/ function with support on the unit hypercube I/sub m/=[0, 1]/sup m/ in the sense of best approximation. An upper bound (O(N/sup -2/)) of the approximation error is obtained in the present paper for a Gaussian network having N/sup m/ hidden neurons with centers defined on a regular mesh in I/sub m/. >
Location-based reasoning about complex multi-agent behavior

Recent research has shown that surprisingly rich models of human activity can be learned from GPS (positional) data. However, most effort to date has concentrated on modeling single individuals or statistical properties of groups of people. Moreover, prior work focused solely on modeling actual successful executions (and not failed or attempted executions) of the activities of interest. We, in contrast, take on the task of understanding human interactions, attempted interactions, and intentions from noisy sensor data in a fully relational multi-agent setting. We use a real-world game of capture the flag to illustrate our approach in a well-defined domain that involves many distinct cooperative and competitive joint activities. We model the domain using Markov logic, a statistical-relational language, and learn a theory that jointly denoises the data and infers occurrences of high-level activities, such as a player capturing an enemy. Our unified model combines constraints imposed by the geometry of the game area, the motion model of the players, and by the rules and dynamics of the game in a probabilistically and logically sound fashion. We show that while it may be impossible to directly detect a multi-agent activity due to sensor noise or malfunction, the occurrence of the activity can still be inferred by considering both its impact on the future behaviors of the people involved as well as the events that could have preceded it. Further, we show that given a model of successfully performed multi-agent activities, along with a set of examples of failed attempts at the same activities, our system automatically learns an augmented model that is capable of recognizing success and failure, as well as goals of people's actions with high accuracy. We compare our approach with other alternatives and show that our unified model, which takes into account not only relationships among individual players, but also relationships among activities over the entire length of a game, although more computationally costly, is significantly more accurate. Finally, we demonstrate that explicitly modeling unsuccessful attempts boosts performance on other important recognition tasks.
Global Capital Flows and Financing Constraints

Firms often cite financing constraints as one of their primary obstacles to investment. Global capital flows, by bringing in scarce capital, may ease the financing constraints of host country firms. But if incoming foreign investors borrow heavily from domestic banks, foreign direct investment may exacerbate financing constraints by crowding host country firms out of domestic capital markets. Combining a unique cross-country firm-level panel with time-series data on restrictions on international transactions and capital flows, Harrison, Love, and McMillan find that different measures of global flows are associated with a reduction in firm-level financing constraints. First, the authors show that one type of capital inflow-foreign direct investment-is associated with a reduction in financing constraints. Second, they test whether restrictions on international transactions affects the financing constraints of firms. The results suggest that only one type of restriction-those on capital account transactions-negatively affects firms' financing constraints. The authors also show that multinational firms are not financially constrained and do not appear to be sensitive to the level of foreign direct investment. This implies that foreign direct investment eases financing constraints for non-multinational firms. Finally, the authors show that (1) foreign direct investment only eases financing constraints in the non-G7 countries, and (2) other kinds of flows, such as portfolio investment, have no impact on financing constraints.
A variational problem on Stiefel manifolds

In their paper on discrete analogues of some classical systems such as the rigid body and the geodesic flow on an ellipsoid, Moser and Veselov introduced their analysis in the general context of flows on Stiefel manifolds. We consider here a general class of continuous time, quadratic cost, optimal control problems on Stiefel manifolds, which in the extreme dimensions again yield these classical physical geodesic flows. We have already shown that this optimal control setting gives a new symmetric representation of the rigid body flow and in this paper we extend this representation to the geodesic flow on the ellipsoid and the more general Stiefel manifold case. The metric we choose on the Stiefel manifolds is the same as that used in the symmetric representation of the rigid body flow and that used by Moser and Veselov. In the extreme cases of the ellipsoid and the rigid body, the geodesic flows are known to be integrable. We obtain the extremal flows using both variational and optimal control approaches and elucidate the structure of the flows on general Stiefel manifolds.
ECONOMIES OF SCALE AND COST EFFICIENCIES: A PANEL‐DATA STOCHASTIC‐FRONTIER ANALYSIS OF REAL ESTATE INVESTMENT TRUSTS*

This paper extends the existing research on real estate investment trust (REIT) operating efficiencies. We estimate a stochastic-frontier, panel-data model specifying a translog cost function, covering 1995–2003. The results disagree with previous research in that we find little evidence of scale economies and some evidence of scale diseconomies. Moreover, we also generally find smaller inefficiencies than those shown by other REIT studies. Contrary to previous research, the results also show that self-management of a REIT associates with more inefficiency when we measure output with assets. When we use revenue to measure output, self-management associates with more efficiency. Also contrary to previous research, higher leverage associates with more efficiency. The results further suggest that inefficiency increases over time in three of our four specifications.
Modeling Altruism and Spitefulness in Experiments

Abstract We examine a simple theory of altruism in which players' payoffs are linear in their own monetary income and their opponents. The weight on the opponent's income is private information and varies in the population, depending, moreover, on what the opponent's coefficient is believed to be. Using results of ultimatum experiments and the final round of a centipede experiment, we are able to pin down relatively accurately what the distribution of altruism (and spite) in the population is. This distribution is then used with a reasonable degree of success to explain the results of the earlier rounds of centipede and the results of some public goods contribution games. In addition, we show that in a market game where the theory of selfish players does quite well, the theory of altruism makes exactly the same predictions as the theory of selfish players. Journal of Economic Literature Classification Numbers: C70, C72, D90, D92.
Dialkynylation of aryl aldehydes using dialkynylboron chlorides: A transition-metal-free route to 1,4-diynes

Abstract Dialkynylboron chlorides couple smoothly with aryl aldehydes at room temperature to afford 1,4-dialkynes in good to excellent yields. Dialkynylboron halides act simultaneously as Lewis acid and reactant in this coupling reaction.
Expected value information improves financial risk taking across the adult life span

When making decisions, individuals must often compensate for cognitive limitations, particularly in the face of advanced age. Recent findings suggest that age-related variability in striatal activity may increase financial risk-taking mistakes in older adults. In two studies, we sought to further characterize neural contributions to optimal financial risk taking and to determine whether decision aids could improve financial risk taking. In Study 1, neuroimaging analyses revealed that individuals whose mesolimbic activation correlated with the expected value estimates of a rational actor made more optimal financial decisions. In Study 2, presentation of expected value information improved decision making in both younger and older adults, but the addition of a distracting secondary task had little impact on decision quality. Remarkably, provision of expected value information improved the performance of older adults to match that of younger adults at baseline. These findings are consistent with the notion that mesolimbic circuits play a critical role in optimal choice, and imply that providing simplified information about expected value may improve financial risk taking across the adult life span.
Fine-grain access control for distributed shared memory

This paper discusses implementations of fine-grain memory access control, which selectively restricts reads and writes to cache-block-sized memory regions. Fine-grain access control forms the basis of efficient cache-coherent shared memory. This paper focuses on low-cost implementations that require little or no additional hardware. These techniques permit efficient implementation of shared memory on a wide range of parallel systems, thereby providing shared-memory codes with a portability previously limited to message passing.This paper categorizes techniques based on where access control is enforced and where access conflicts are handled. We incorporated three techniques that require no additional hardware into Blizzard, a system that supports distributed shared memory on the CM-5. The first adds a software lookup before each shared-memory reference by modifying the program's executable. The second uses the memory's error correcting code (ECC) as cache-block valid bits. The third is a hybrid. The software technique ranged from slightly faster to two times slower than the ECC approach. Blizzard's performance is roughly comparable to a hardware shared-memory machine. These results argue that clusters of workstations or personal computers with networks comparable to the CM-5's will be able to support the same shared-memory interfaces as supercomputers.
Implementing signatures for C

We outline the design and detail the implementation of a language extension for abstracting types and for decoupling subtyping and inheritance in C++. This extension gives the user more of the flexibility of dynamic typing while retaining the efficiency and security of static typing. After a brief discussion of syntax and semantics of this language extension and examples of its use, we present and analyze three different implementation techniques: a preprocessor to a C++ compiler, an implementation in the front end of a C++ compiler, and a low-level implementation with back-end support. We follow with an analysis of the performance of the three implementation techniques and show that our extension actually allows subtype polymorphism to be implemented more efficiently than with virtual functions. We conclude with a discussion of the lessons we learned for future programming language design.
Cu-catalyzed transannulation reaction of pyridotriazoles with terminal alkynes under aerobic conditions: efficient synthesis of indolizines

A Cu(I)-catalyzed denitrogenative transannulation reaction of pyridotriazoles with terminal alkynes en route to indolizines was developed. Compared to the previously reported Rh-catalyzed transannulation reaction, this Cu-catalyzed method features aerobic conditions and a much broader scope of pyridotriazoles and alkynes.