cssi/SciSciGPT-SciSciNet huggingface dataset:
Exact spectral asymptotics on the Sierpinski gasket

One of the ways that analysis on fractals is more complicated than analysis on manifolds is that the asymptotic behavior of the spectral counting function $N(t)$ has a power law modulated by a nonconstant multiplicatively periodic function. Nevertheless, we show that for the Sierpinski gasket it is possible to write an exact formula, with no remainder term, valid for almost every $t$. This is a stronger result than is valid on manifolds.
Exclusion of Cosmic Rays in Protoplanetary Disks: Stellar and Magnetic Effects

Cosmic rays (CRs) are thought to provide an important source of ionization in the outermost and densest regions of protoplanetary disks; however, it is unknown to what degree they are physically present. As is observed in the solar system, stellar winds can inhibit the propagation of CRs within the circumstellar environment and subsequently into the disk. In this work, we explore the hitherto neglected effects of CR modulation by both stellar winds and magnetic field structures and study how these processes act to reduce disk ionization rates. We construct a two-dimensional protoplanetary disk model of a T-Tauri star system, focusing on ionization from stellar and interstellar FUV, stellar X-ray photons, and CRs. We show that stellar winds can power a heliosphere-like analog, i.e., a ''T-Tauriosphere,'' diminishing CR ionization rates by several orders of magnitude at low to moderate CR energies (E{sub CR} {<=} 1 GeV). We explore models of both the observed solar wind CR modulation and a highly simplified estimate for ''elevated'' CR modulation as would be expected from a young T-Tauri star. In the former (solar analog) case, we estimate the ionization rate from galactic CRs to be {zeta}{sub CR} {approx} (0.23-1.4) Multiplication-Sign 10{sup -18} s{sup -1}. Thismore » range of values, which we consider to be the maximum CR ionization rate for the disk, is more than an order of magnitude lower than what is generally assumed in current models for disk chemistry and physics. In the latter elevated case, i.e., for a ''T-Tauriosphere,'' the ionization rate by CRs is {zeta}{sub CR} {approx}< 10{sup -20} s{sup -1}, which is 1000 times smaller than the interstellar value. We discuss the implications of a diminished CR ionization rate on the gas physics by estimating the size of the resulting magnetorotational instability dead zones. Indeed, if winds are as efficient at CR modulation as predicted here, short-lived radionuclides (now extinct) would have provided the major source of ionization ({zeta}{sub RN} {approx} 7.3 Multiplication-Sign 10{sup -19} s{sup -1}) in the planet-forming zone of the young solar nebula.« less
Catalytic Enantioselective Cross-Couplings of Secondary Alkyl Electrophiles with Secondary Alkylmetal Nucleophiles: Negishi Reactions of Racemic Benzylic Bromides with Achiral Alkylzinc Reagents

We have developed a nickel-catalyzed method for the asymmetric cross-coupling of secondary electrophiles with secondary nucleophiles, specifically, stereoconvergent Negishi reactions of racemic benzylic bromides with achiral cycloalkylzinc reagents. In contrast to most previous studies of enantioselective Negishi cross-couplings, tridentate pybox ligands are ineffective in this process; however, a new, readily available bidentate isoquinoline–oxazoline ligand furnishes excellent ee’s and good yields. The use of acyclic alkylzinc reagents as coupling partners led to the discovery of a highly unusual isomerization that generates a significant quantity of a branched cross-coupling product from an unbranched nucleophile.
Shock-induced CO2 loss from CaCO3; implications for early planetary atmospheres

Recovered samples from shock recovery experiments on single crystal calcite were subjected to thermogravimetric analysis to determine the amount of post-shock CO2, the decarbonization interval and the activation energy, for the removal of remaining CO2 in shock-loaded calcite. Comparison of post-shock CO2 with that initially present determines shock-induced CO2 loss as a function of shock pressure. Incipient to complete CO2 loss occurs over a pressure range of approximately 10 to approximately 70 GPa. Optical and scanning electron microscopy reveal structural changes, which are related to the shock-loading. The occurrence of dark, diffuse areas, which can be resolved as highly vesicular areas as observed with a scanning electron microscope are interpreted as representing quenched partial melts, into which shock-released CO2 was injected. The experimental results are used to constrain models of shock-produced, primary CO2 atmospheres on the accreting terrestrial planets.
The Effects of Starburst Activity on Low Surface Brightness Disk Galaxies

Although numerous simulations have been done to understand the effects of intense bursts of star formation on high surface brightness galaxies, few attempts have been made to understand how localized starbursts would affect both the color and surface brightness of low surface brightness (LSB) galaxies. To remedy this, we have run 53 simulations involving bursts of star formation activity on LSB galaxies, varying both the underlying galaxy properties and the parameters describing the starbursts. We discovered that although changing the total color of a galaxy was fairly straightforward, it was virtually impossible to alter a galaxy's central surface brightness and thereby remove it from the LSB galaxy classification without placing a high (and fairly artificial) threshold for the underlying gas density. The primary effect of large amounts of induced star formation was to produce a centralized core (bulge) component, which is generally not observed in LSB galaxies. The noisy morphological appearance of LSB galaxies, as well as their noisy surface brightness profiles, can be reproduced by considering small bursts of star formation that are localized within the disk. The trigger mechanism for such bursts is likely distant/weak tidal encounters. The stability of disk central surface brightness to these periods of star formation argues that the large space density of LSB galaxies at z = 0 should hold to substantially higher redshifts.
An aerodynamic analysis of several hypersonic research airplane concepts from M = 0.2 to 6.0

Several conceptual hypersonic research airplanes, designed within the constraints of a B-52 launch aircraft, have been studied experimentally and analytically at Mach numbers from 0.2 to 6.0. Vehicles built to these criteria for Mach 6 cruise were shown to be feasible, if careful attention was paid to the low speed lift, drag, and high angle of attack stability to assure successful landings and transonic pitch angle maneuvers. The integrated scramjet engine drag was high at subsonic speeds and appears to be constant with Reynolds number. The variable geometry airfoil used previously to improve directional stability was shown to be equally adaptable to the improvement of longitudinal stability. The vortex lattice theory gave good subsonic predictions of lift, drag due to lift, and pitching moments. Wind tunnel tests must be relied on for the drag at zero lift, trim, static margins and lateral-directional stability. The Gentry Hypersonic Arbitrary Body Program gave good predictions of the trends of lift, drag, and pitching moments with angle of attack at Mach numbers above 3, but the level of the values were not consistently predicted. No currently available theory or program gave accurate predictions of directional stability or dihedral effects at hypersonic speeds.
Household Water Supply Choice and Time Allocated to Water Collection: Evidence from Madagascar

Abstract This article uses household survey data from Madagascar to examine water supply choice and time spent in water collection. We find that the choice of water source is strongly influenced by a number of household characteristics, as well as distance to sources. There are also strong substitution effects across sources. For example, increasing the distance to a public tap by 1 km increases the probability of using a well by 43 per cent in urban areas. With regards to time spent gathering water, we focus on the effects of gender, age, and distance to water. Women and girls spend the most time gathering water. The response to reducing distance to water sources differs in rural and urban areas, as well as by gender and age of household members. Investments to reduce to the distance to water sources will have larger impacts on adults than children, and on men than women.
Monte Carlo Simulation of the Growth of ZnSe by MBE

A Monte Carlo study of the growth of ZnSe by Molecular beam epitaxy is presented. The study is focused on the role of surface kinetic reactions on the structural quality of the epilayers. Two different models for the incorporation of Se molecules, one with a highly reactive physisorbed state and the other with a relatively nonreactive physisorbed state are employed for simulations. It is shown that the structural quality of the epilayers is very sensitive to the flux ratio if the physisorbed state is relatively nonreactive. It is also shown that if the physisorbed state is highly reactive, good quality epilayers are obtained over a wide range of flux ratio.
A novel cycloalkylation of 1,6- and 1,7-enynes with stabilized pronucleophiles

Abstract Formation of five and six membered rings simultaneously with addition of a functionalized side chain for further elaboration occurred upon exposing a 1:1 mixture of an enyne and a pronucleophile to a palladium catalyst derived from Pd(OAc) 2 and a bidentate ligand.
NASA RESEARCH ON FLEXIBLE WINGS

NASA research on flexible and stiffened flexible wings, discussing range of applicability, aerodynamic characteristics and wind tunnel results
Global Regularity of Solutions to Systems of Reaction–Diffusion with Sub-Quadratic Growth in Any Dimension

This paper is devoted to the study of the regularity of solutions to some systems of reaction–diffusion equations, with reaction terms having a subquadratic growth. We show the global boundedness a...
Output processes of slotted persistent CSMA and CSMA/CD systems

Abstract Stochastic analysis is given for the interval between two successive successful transmissions (called the packet interdeparture time) in a variety of slotted persistent CSMA and CSMA/CD systems; they include DFT (Delay-First-Transmission) and IFT (Immediate-First-Transmission) models, and we assume that unsuccessfully transmitted packets are either discarded or retransmitted. The analyses for individual models follow our unified formulation of a generic output process. The channel throughput (given by the reciprocal of the mean packet interdeparture time) and the coefficient of variation of the packet interdeparture time are computed for some sets of parameter values.
“Not just a taxi”? For-profit ridesharing, driver strategies, and VMT

The spread of GPS-based location services using smartphone applications has led to the rapid growth of new startups offering smartphone-enabled dispatch service for taxicabs, limousines, and ridesharing vehicles. This change in communicative technology has been accompanied by the creation of new categories of car service, particularly as drivers of limousines and private vehicles use the apps to provide on-demand service of a kind previously reserved for taxicabs. One of the most controversial new models of car service is for-profit ridesharing, which combines the for-profit model of taxi service with the overall traffic reduction goals of ridesharing. A preliminary attempt is here made at understanding how for-profit ridesharing compares to traditional taxicab and ridesharing models. Ethnographic interviews are drawn on to illustrate the range of motivations and strategies used by for-profit ridesharing drivers in San Francisco, California as they make use of the service. A range of driver strategies is identified, ranging from incidental, to part-time, to full-time driving. This makes possible a provisional account of the potential ecological impacts of the spread of this model of car service, based on the concept of taxicab efficiency, conceived as the ratio of shared versus unshared miles driven.
Pericyclic Reactions of Radical Cations

Electron transfer catalysis is an efficient method for the catalysis of symmetry-forbidden or slow pericyclic reactions. Accurate quantum mechanical calculations are an important tool for gaining insights into the mechanistic details of these fast reactions involving radical cations. The current “state of the art” of computational studies of pericyclic reactions of radical cations is reviewed. In particular, four parent reaction types are discussed: (i) the ring-opening of the cyclobutane radical cation; (ii) the [2+2] cycloreversion of the cyclobutane radical cation; (iii) the radical cation Diels−Alder reaction of 1,3-butadiene and ethylene; and (iv) the [1,3] methylene shift in the vinylcyclopropane radical cation. The transfer of these findings to chemically more relevant substituted systems is also briefly discussed. The potential energy hypersurfaces obtained are very flat and have activation barriers that are significantly lower than the ones for the corresponding neutral reactions, which is in agreement with the large rate acceleration observed experimentally. Many of the located radical cation structures closely resemble their biradical counterparts in the neutral, stepwise pathways. The reactions generally follow a lower symmetry pathway, due to Jahn−Teller distortions induced by the unpaired electron. Finally, the results from computationally efficient B3LYP/6-31G* calculations are found to be in good agreement with those from highly correlated MO calculations.
Suzuki–Miyaura arylations of tetramic acid sulfonates: Evaluation of lactam protection, sulfonate esters, and sterics

The synthesis of 3,4-diaryl-3-pyrrolin-2-ones and 4-aryl-3-pyrrolin-2-ones using Suzuki–Miyaura cross-coupling reactions of tetramic acid sulfonates with arylboronic acids has been studied. The effect that sulfonate ester, sterics, and lactam protection has on the cross-coupling reaction was evaluated. As expected, triflates were better cross-coupling partners than the corresponding tosylates. The yields were only partially affected by the incorporation of aryl groups at the 3-position. Importantly, tetramic acid triflates (and to a lesser extent tosylates) lacking a lactam protecting group were still competent substrates. J. Heterocyclic Chem., 46, 447 (2009).
Common-mode/Common-cause failure: A review

Abstract Common-mode/common-cause (CM/CC) failure and its prevention has been a serious concern in the nuclear safety community during the past few years. Since redundancy was first used in an attempt to achieve high reliability in systems, the CM/CC failure phenomenon has been inherent in system designs. The concern is that high-reliability systems are subject to compromise by human error and environmental factors. Potential CM/CC failures are the result of adding complexity to system designs. They are the product of a supersafe philosophy. This article reviews the CM/CC failure phenomenon. Classes of CM/CC failures are compiled, and the defenses against such failures and their weaknesses are surveyed. Some regulatory considerations, operating experiences, and reliability analysis methodology are touched upon.
Plutonium and americium processing chemistry and technology

Description des procedes de purification de plutonium et de recuperation de purification de l'americium utilises dans l'usine de Rocky Flats
Cluster of clusters: A new series of high nuclearity Au-Ag clusters

Abstract The structure of a novel series of bimetallic Au-Ag clusters containing 25 (Au 13 Ag 12 ), 37 (Au 18 Ag 19 ), and 38 (Au 18 Ag 20 ) metal atoms is discussed. The most interesting structural characteristic of these clusters is that they can be considered as being built from 13-atom centred icosahedral cluster units. Thus, the 25-atom cluster can be considered as two icosahedra sharing a vertex; the 37− and 38-atom clusters as three icosahedra sharing three vertices in a cyclic manner plus one and two capping atoms, respectively. These observations led to the concept of “cluster of clusters”. It is predicted that tetrahedral, trigonal-bipyramidal, and pentagonal-bipyramidal arrays of vertex-sharing icosahedra will give rise to nuclearities (10 n + 6) of 46−, 56− and 76-atom clusters, respectively. One exception to the rule is the 127-atom icosahedral cluster which is formed by 12 centred icosahedra sharing 30 corners. Here the icosahedral hole created by the 12 icosahedra is filled with one additional atom. It is suggested that the idea of “cluster of clusters” may provide new pathways to novel high nuclearity supraclusters via vertex-, edge-, and face-sharing and/or close-packing of smaller cluster units as building blocks.
Excess number of percolation clusters on the surface of a sphere

Abstract Monte Carlo simulations were performed in order to determine the excess number of clusters b and the average density of clusters nc for the two-dimensional “Swiss cheese” continuum percolation model on a planar L×L system and on the surface of a sphere. The excess number of clusters for the L×L system was confirmed to be a universal quantity with a value b=0.8841 as previously predicted and verified only for lattice percolation. The excess number of clusters on the surface of a sphere was found to have the value b=1.215(1) for discs with the same coverage as the flat critical system. Finally, the average critical density of clusters was calculated for continuum systems as nc=0.04075(5).
Worry, Generalized Anxiety Disorder, and Emotion: Evidence from the EEG Gamma Band

The present study examined EEG gamma (35-70 Hz) spectral power distributions during worry inductions in participants suffering from generalized anxiety disorder (GAD) and in control participants without a history of psychiatric illness. As hypothesized, the EEG gamma band was useful for differentiating worry from baseline and relaxation. During worry induction, GAD patients showed higher levels of gamma activity than control participants in posterior electrode sites that have been previously associated with negative emotion. Gamma fluctuations in these electrode sites were correlated with subjective emotional experience ratings lending additional support to interpretations of negative affect. Following 14 weeks of psychotherapy, the GAD group reported less negative affect with worry inductions and the corresponding gamma sites that previously differentiated the clinical from control groups changed for the GAD patients in the direction of control participants. These findings suggest converging evidence that patients suffering from GAD experience more negative emotion during worry and that the EEG gamma band is useful for monitoring fluctuations in pathological worry expected to follow successful treatment.
Postoperative Management of Crohn Disease

Crohn disease often recurs after surgical resection. Despite extensive research in the prevention of postoperative Crohn disease, optimal management strategies have yet to be defined. Risk of disease recurrence needs to be carefully balanced against potential risks associated with treatment. Patients with low risk of postoperative recurrence may not require medication, whereas those at moderate risk may benefit from antibiotics or immunomodulators. Those at highest risk of recurrence may benefit from biologic therapy for maintenance of surgical remission. Postoperative colonoscopy within 1 year of resective surgery is important for identification of disease recurrence and modification of medications.
Beliefs and rationalizability in games with complementarities

We propose two characteristics of players' beliefs and study their role in shaping the set of rationalizable strategy profiles in games with incomplete information. The first characteristic, type-sensitivity, is related to how informative a player thinks his type is. The second characteristic, optimism, is related to how "favorable" a player expects the outcome of the game to be. The paper has two main results: the first result provides an upper bound on the size of the set of rationalizable strategy profiles, the second gives a lower bound on the change of location of this set. These bounds have explicit and relatively simple expressions that feature type-sensitivity, optimism, and properties of the payoffs. Our results generalize and clarify the well-known uniqueness result of global games (Carlsson and van Damme (1993)). They imply new uniqueness results and allow to study rationalizability in new environments. We provide applications to supermodular mechanism design (Mathevet (2010)) and non-Bayesian updating (Epstein (2006)).
DINOFLAGELLATE BIOLUMINESCENCE : THE CHROMOPHORE OF DINOFLAGELLATE LUCIFERIN

Abstract A concise synthesis of the chromophore proposed for dinoflagellate luciferin was accomplished. The chemical behavior towards molecular oxygen and spectroscopic characteristics of the synthetic chromophore were found to match well with those observed for dinoflagellate luciferin. Comparison of the 13C chemical shifts observed for the E- and Z-isomers of the synthetic model with those observed for dinoflagellate luciferin suggested the natural luciferin to have an E-configuration about its C.15–C.16 olefinic bond.
Array requirements for scientific applications and an implementation for microsoft SQL server

This paper outlines certain scenarios from the fields of astrophysics and fluid dynamics simulations which require high performance data warehouses that support array data type. A common feature of all these use cases is that subsetting and preprocessing the data on the server side (as far as possible inside the database server process) is necessary to avoid the client-server overhead and to minimize IO utilization. Analyzing and summarizing the requirements of the various fields help software engineers to come up with a comprehensive design of an array extension to relational database systems that covers a wide range of scientific applications.We also present a working implementation of an array data type for Microsoft SQL Server 2008 to support large-scale scientific applications. We introduce the design of the array type, results from a performance evaluation, and discuss the lessons learned from this implementation. The library can be downloaded from our website at http://voservices.net/sqlarray/.
Leading corporate citizenship: governance, structure, systems

Purpose – The purpose of this paper is to benchmark how 25 companies in five industries are addressing corporate citizenship through their governance, structures and systems. The paper aims to look at patterns of leadership practice developing in firms in this regard and what might be shaping them. It also seeks to consider current practices in light of movement toward next‐generation corporate citizenship.Design/methodology/approach – The study surveyed a representative sample of Fortune 500 companies. To benchmark how companies are embedding citizenship into their governance, structure, and systems, two scorecards were devised measuring practices pertaining to: Corporate Board Governance; and Operational Management of Corporate Citizenship. Criteria chosen represent Board and management policies, behaviors, and/or public commitments.Findings – It was found that, while corporate Boards are assuming more responsibility for oversight of conduct and taking account of specific social and environmental issues...
Electrical Properties of Individual Zinc Oxide Grain Boundaries Determined by Spatially Resolved Tunneling Spectroscopy

Scanning tunneling microscopy (STM) and spatially resolved tunneling spectroscopy (TS) were used to observe correlations between the geometric structure and electrical properties of polycrystalline ZnO surfaces under ultrahigh vacuum. Constant current images revealed crystallographic features at a range of length scales, including facets which are hundreds of nanometers long and monoatomic steps ≅0.5 nm (≅5 A) in height. Tunneling spectroscopy was used to identify individual ZnO grains, grain boundaries, and surface impurities. Areas of reduced conductivity which extend 5 to 40 nm (50 to 400 A) on either side of the grain boundaries are attributed to associated space charge regions. This paper demonstrates that, when used together, STM and TS are powerful techniques for the study of the structure and electrical properties of single interfaces and grain boundaries.
Data-parallel total variation diminishing method for sonic boom calculations

Sonic boom predictions are shown for the near and midfield and comparisons are made with experimental data. The computations are performed on the Thinking Machines' CM-5 massively parallel supercomputer to utilize its large available memory and high floating point performance. A second-order-accurate total variation diminishing scheme is used to solve the Euler equations in the computations. Additionally, a recently developed implicit method, based on the LU-SGS algorithm, is used to speed the convergence and accuracy of the steady- state computations. The method is shown to work well on near- and midfield sonic boom predictions for several test cases. HE projected use of the high speed civil transport (HSCT) has drawn attention to the problems associated with the noise due to sonic booms.1 An accurate and efficient sonic boom prediction methodology is needed for the assessment of various proposed HSCT configurations. One such method that utilizes the power of massively parallel supercomputers is presented here. A review of current sonic boom prediction methods is given by Plotkin.2 Many of these methods are based on the modified linear analysis of Whitham 3 and Walkden.4 Other methods have been developed based on a modified method of char- acteristics that approximately account for the effects of three- dimensional flows. Experimental and analytical studies have shown that these methods lose effectiveness as freestream Mach number approaches 3. In high Mach number regions there are strong shock waves with significant entropy gen- eration. The linear-based methods neglect these production terms.5 A modified method of characteristi cs has been de- veloped that can account for these terms,6 but it requires nonlinear near-field initial data that is difficult to obtain com- putationally or experimentall y. Several authors have developed prediction methods based on near-field solutions of the Euler or Navier-Stokes equa- tions.7-8 Most of these methods involve marching in one spatial dimension with an implicit Euler scheme or a parabolized Navier-Stokes (PNS) algorithm. These solutions are used in conjuction with Whitham's F-function to evaluate the far-field pressure signature. The existing prediction methods are un- attractive for several reasons. First, additional accuracy in the marching direction greatly increases the computational time. Also, they do not employ methods designed to resolve shock waves effectively. Finally, they are not easily implemented on massively parallel supercomputers. Accurate shock resolution is needed in the computational fluid dynamic (CFD) methods to determine the far-field pres- sure signature effectively. Since the prediction methods are dependent on shock resolution it is desirable to use a com- putational method that is designed to capture shock waves. The total variation diminishing (TVD) schemes developed by Harten,9 Yee,10 and others are well suited for this purpose. In this study a second-order-accurate TVD scheme is used to determine the pressure field about several models. These so- lutions are then compared with experiment.
Intraoperative transcranial doppler ultrasound in head and neck surgery: A preliminary report

Abstract Purpose: To evaluate the possible role of intraoperative cerebral emboli in the origin of perioperative stroke during major head and neck surgical procedures. Materials and Methods: Eleven patients undergoing major head and neck surgery that involved direct manipulation of the carotid sheath were the participants in this study. Transcranial Doppler (TCD) ultrasound was used intraoperatively to detect possible cerebral emboli. The presence or absence of intraoperative cerebral emboli in each patient was assessed by the presence or absence of typical embolic signal patterns within the TCD waveform. Results: No intraoperative cerebral emboli were noted in the series, nor did any patient have a postoperative stroke. Conclusions: No intraoperative cerebral emboli were noted by using TCD ultrasound for embolus monitoring in patients undergoing major head and neck surgery involving carotid sheath manipulation. This detection system is easily used in appropriate head and neck cases and allows real-time, noninvasive intraoperative monitoring.
PROPERTIES OF BARIUM‐STRONTIUM TITANATE DIELECTRICS*

The results on barium-strontium titanates are given for heat-treatment, absorption, shrinkage, thermal expansion, dielectric constant, K, at minus 60° to 85°C. and also for Q (the reciprocal of the power factor) at 25°C. for frequencies of 50 kc. per sec. to 20 mc. per sec. A few measurements of K and Q were made at 3000 mc. per sec. Specimens with an absorption of less than 0.l% matured at 1250° to 1430°C. K values ranged from 34 for BaO:4TiO2 to several thousand for specimens with compositions on the BaTiO3-SrTiO3 join. The BaO: 5TiO2 specimens were unique in that their temperature coefficient of K was practically zero. O values ranged from 50 to 100 for test pieces containing more than 40% of BaO and from 400 to 10,000 for those with less than 40% of BaO. K values did not change appreciably with frequency. Linear thermal expansions (between 25° and 700°C.) ranged from 0.6 to 0.84%. Many of these specimens could be used in radio equipment.
New two-color dimer models with critical ground states

We define two new models on the square lattice in which each allowed configuration is a superposition of a covering by “white” dimers and one by “black” dimers. Each model maps to a solid-on-solid (SOS) model in which the “height” field is two dimensional. Measuring the stiffness of the SOS fluctuations in the rough phase provides critical exponents of the dimer models. Using this “height” representation, we have performed Monte Carlo simulations. They confirm that each dimer model has critical correlations and belongs to a new universality class. In the “dimer-loop” model (which maps to a loop model) one height component is smooth, but has unusual correlated fluctuations; the other height component is rough. In the “noncrossing-dimer” model the heights are rough, having two different elastic constants; an unusual form of its elastic theory implies anisotropic critical correlations.
Costs and Benefits of Requiring an Engagement Partner Signature: Recent Experience in the United Kingdom

ABSTRACT: This paper investigates the effects on audit quality and audit fees of requiring the engagement partner to sign the audit report in the United Kingdom (U.K.). The effect of requiring the engagement partner to sign the audit report is timely since the Public Company Accounting Oversight Board (PCAOB) is considering mandating a similar requirement in the United States (U.S.). In the first year after the introduction of the signature requirement, we find a significant decline in abnormal accruals and the propensity to meet an earnings threshold, and we find a significant increase in the incidence of qualified audit reports and in earnings informativeness. In addition, audit fees are significantly higher in the post-signature period than in the pre-signature period. Moreover, we compare U.K. firms with a matched sample of U.S. firms and firms in other European countries in periods both before and after the U.K. adopted a signature requirement. Our results are generally consistent with the argument o...
Self-Consistent Micromechanics Models of an Asphalt Mixture

An asphalt mixture is a composite material consisting of three components: asphalt binder, aggregate, and air. The mechanical properties of asphalt mixtures are mostly evaluated from empirical approaches that are usually limited to measurement conditions. This paper takes a mechanistic approach by using micromechanics theory for composite materials to develop self-consistent micromechanics models for an asphalt mixture. The mixture analysis method described in this paper is applied to measured properties of an asphalt concrete mixture that is commonly used in Texas. These models are programmed in MATLAB using the system identification method and are applied to the analysis of the frequency-dependent magnitudes of the viscoelastic properties of an asphalt mixture at different aging periods. The inverse micromechanics model takes as input the volumetric composition of the mixture and the measured frequency-dependent bulk and shear properties of the asphalt mixture and the binder and extracts from them the bulk and shear properties of the aggregate. The forward micromechanics model takes as input the frequency-dependent bulk and shear properties of the aggregate and binder and produces the frequency-dependent properties of the asphalt mixture. It has been demonstrated that the inverse and forward micromechanics models are in fact the inverse of each other and that the inferred aggregate properties are realistic. These models provide a technique to catalog the properties of aggregates and use them in a computerized determination of the combinations of binders, aggregates, and air to produce the desired properties of asphalt mixtures.
On universality of charge transport in AdS/CFT

We develop the holographic formulation of transport in strongly coupled two-layer systems. We identify a dc conductivity, σ dc, that is finite even in a translationally invariant setup, and universal for CFTs with a gravity dual. The thermoelectric conductivity and heat conductivity are fully determined by the electrical conductivity matrix, as a consequence of Ward identities. We use the memory-matrix approach for double-layer systems, together with Ward identities, to show that σ dc — extended to finite frequency — has no Drude peak and, similarly, that its universal value is unaffected if translation-invariance is softly broken.
A special case of effective equidistribution with explicit constants

An effective equidistribution with explicit constants for the isometry group of rational forms with signature (2,1) is proved. As an application we get an effective discreteness of the Markov spectrum.
Soft input soft output Kalman equalizer for MIMO frequency selective fading channels

We consider the Kalman filter for equalization of a multiple-input multiple-output (MIMO), frequency selective, quasi-static fading channel. More specifically, we consider a coded system, where the incoming bit stream is convolutionally encoded, interleaved and then spatially multiplexed across the transmit antennas. Each substream is modulated into M-ary symbols before being transmitted over a frequency selective channel. At the receiver, we propose to use the Kalman filter as a low complexity MIMO equalizer, as opposed to the trellis based maximum a-posteriori (MAP) equalizer whose computational complexity grows exponentially with the channel memory, the number of transmit antennas and the spectral efficiency (bits/s/Hz) of the system. We modify the structure of the Kalman filter and enable it to process the a-priori (soft) information provided by the channel decoder, thereby allowing us to perform iterative (turbo) equalization on the received sequence. The iterative equalizer structure is designed for general M-ary constellations. We also propose a low complexity version of the above algorithm whose performance is comparable to its full complexity counterpart, but which achieves a significant complexity reduction. We demonstrate via simulations that for higher order constellations, when sufficient number of receive antennas are available (e.g. for a 2 transmitter, 3 receiver system, QPSK), the performance of the proposed algorithms after 4 iterations is within 1.5 dB of the non-iterative MAP algorithm with close to an order of magnitude complexity reduction. By objectively quantifying the complexity of all the considered algorithms we show that the complexity reduction for the proposed schemes becomes increasingly significant for practical systems with moderate to large constellation sizes and a large number of transmit antennas
Spread Spectrum Orthogonal Frequency Coded SAW Tags and Sensors Using Harmonic Operation

This paper presents a preliminary investigation of orthogonal frequency coding (OFC) surface acoustic wave tags and sensors at a 500- and 900-MHz operational frequency range using conventional contact lithography techniques. The higher frequency devices are achieved using second harmonic operation; eliminating the need for advanced lithography techniques. The objective of this effort is to increase the technology readiness level of wideband OFC tags at higher frequencies. Measured device results are presented and compared with coupling of modes model predictions to demonstrate performance. The fundamental and harmonic device response is compared for devices designed for operation in the 900-MHz frequency band. The experimental correlation against an ideal matched filter is also presented.
Scope and diastereoselectivity of the "interrupted" Feist-Bénary reaction.

The base-promoted condensation of β-dicarbonyl compounds with α-haloketones, the Feist−Benary reaction, conveniently produces highly substituted dihydrofurans. We show here that this reaction is quite general with respect to the nature of the β-dicarbonyl compound, proceeding with β-ketoesters, β-oxopropionates, β-diketones, and β-dialdehydes. We also show that the diastereoselectivity of this reaction depends on the acidity of the nucleophile.
FAWN: a fast array of wimpy nodes

This paper presents a fast array of wimpy nodes---FAWN---an approach for achieving low-power data-intensive data-center computing. FAWN couples low-power processors to small amounts of local flash storage, balancing computation and I/O capabilities. FAWN optimizes for per node energy efficiency to enable efficient, massively parallel access to data. The key contributions of this paper are the principles of the FAWN approach and the design and implementation of FAWN-KV---a consistent, replicated, highly available, and high-performance key-value storage system built on a FAWN prototype. Our design centers around purely log-structured datastores that provide the basis for high performance on flash storage, as well as for replication and consistency obtained using chain replication on a consistent hashing ring. Our evaluation demonstrates that FAWN clusters can handle roughly 350 key-value queries per Joule of energy---two orders of magnitude more than a disk-based system.
Do hep neutrinos affect the solar neutrino energy spectrum

Abstract If the low energy cross section for 3 He +p→ 4 He +e + +ν e , the `hep' reaction, is ≳20 times larger than the best (but uncertain) theoretical estimates, then this reaction could significantly influence the electron energy spectrum produced by solar neutrino interactions and measured in the SuperKamiokande, SNO, and ICARUS experiments. We compare predicted energy spectra for different assumed hep fluxes and different neutrino oscillation scenarios with the observed SuperKamiokande spectrum. The spectra with enhanced hep contributions provide better fits to the SuperKamiokande data.
Transboundary pollution game with potential shift in damages

Abstract Complex systems exposed to pollution may suddenly and permanently shift to a dangerous regime. This paper studies a dynamic game among countries that face the prospect of such a shift. Each country derives some flow utility from its own emissions, which are chosen unilaterally. But flow emissions by all countries increase the pollution stock in the world. In addition to generating global damages such as global warming, the pollution stock may trigger an irreversible and abrupt jump in global damages or catastrophe at an unknown date in the future. We ask whether endogenous and exogenous threats of such a jump in damages or catastrophe mitigate the tragedy of the commons and examine their implications on welfare. Our analysis yields different emission responses to these threats as compared to the related literature that focuses only on the single-polluter case. For example, when the hazard rate is exogenous and countries commit to nonlinear strategies, we find that the threat of a possible jump in damages or catastrophe may induce a lower or larger emission level and initial welfare due to multiple equilibria. These results are maintained when the hazard rate endogenously depends on emission decisions.
The roles of altitude and fear in the perception of height

Previous research on perceiving spatial layout has found that people often exhibit normative biases in their perception of the environment. For instance, slant is typically overestimated and distance is usually underestimated. Surprisingly, however, the perception of height has rarely been studied. The present experiments examined the perception of height when viewed from the top (e.g., looking down) or from the bottom (e.g., looking up). Multiple measures were adapted from previous studies of horizontal extents to assess the perception of height. Across all of the measures, a large, consistent bias was found: Vertical distances were greatly overestimated, especially from the top. Secondary findings suggest that the overestimation of distance and size that occurs when looking down from a high place correlates with reports of trait- and state-level fear of heights, suggesting that height overestimation may be due, in part, to fear.
Halocycloalkenones as Diels–Alder Dienophiles. Applications to Generating Useful Structural Patterns

Halocycloalkenones are demonstrated to function as potent dienophiles in inter- and intramolecular Diels–Alder cycloadditions. We have found 2-brominated cycloalkenone dienophiles to be both highly endo selective and significantly more reactive than their nonhalogenated parent compounds. A method for the facile conversion of brominated cyclobutanone DA adducts to synthetically useful cyclopropyl functional handles is described.
The effect of Reynolds number on boattail drag

An investigation has been conducted in the Langley pilot transonic cryogenic tunnel to determine the effects of varying Reynolds number on boattail drag at subsonic speeds. Six boattailed cone-cylinder nacelle models were tested with the jet exhaust simulated by a cylindrical sting. Reynolds number was varied from about 2.6 million to 132 million by changing model length and unit Reynolds number. Boattail pressure coefficient distributions show that increasing Reynolds number tends to make the pressure coefficients in the expansion region more negative and the pressure coefficients in the recompression region more positive. These two effects were compensating and as a result there was little or no effect of Reynolds number on the pressure drag of the isolated boattails.
Heredity and Prostate Cancer: A Study of World War II Veteran Twins

BACKGROUND Increased risk of prostate cancer among men with a family history of the disease has been observed in several epidemiological studies, and family studies have identified hereditary prostate cancer characterized by early onset and autosomal dominant inheritance. METHODS In this study, we examine prostate cancer heritability among twins in the NAS-NRC Twin Registry, with cases ascertained from a number of sources: recent telephone interviews, Medicare and Department of Veterans Affairs hospitalizations, previous mail questionnaires, and death certificates. A total of 1,009 prostate cancer cases were identified among the cohort of 31,848 veteran twins born in the years 1917–1927. RESULTS Probandwise concordance for prostate cancer was substantially higher among monozygous twin pairs, 27.1%, than among dizygous twin pairs, 7.1% (P < 0.001). CONCLUSIONS These data suggest that genetic influences account for approximately 57%, and environmental influences for 43%, of the variability in twin liability for prostate cancer. Prostate 33:240–245, 1997. © 1997 Wiley-Liss, Inc.
Hemi-thioacetal Pummerer reaction for the synthesis of gliovirin benzylic sulfide models

Abstract The cyclic hemithioacetal sulfoxide 15 readily undergoes the Pummerer reaction in the presence of carbon nucleophiles to give substituted benzylic sulfides in excellent yields.
Voting for Change: Calculation, Community, and Euro Referendums

Referendum votes on adoption of the euro in Denmark (2000) and Sweden (2003) provide unprecedented natural experiments through which to study the political economy of money. Using exit polling data and multinomial logit statistical models that allow us to separate preferences for the euro from preferences for the European Union (EU), we test economic “calculation” and political “community” as determinants of individual-level preferences over adoption of the euro. We find that “calculation” operates most clearly where, as in Sweden, the choice of a fixed versus a floating exchange rate regime is at stake, while “community” exerts strong effects across the two cases.We would like to thank Krister Andersson, Jerry Cohen, Robert Fishman, Jennifer Fitzgerald, Jeff Frieden, Eric Helleiner, Jacques Hymans, Lars Jonung, Kate McNamara, Jennifer Wolak, and the anonymous reviewers for helpful comments, and Helga Sverrisdottir for outstanding research assistance. We are grateful to Jens Wagner of the Danish Data Archive and Torbjorn Berglund of the Swedish Social Science Dataservice for providing the data used in this note. Neither these individuals nor their respective agencies are responsible for the interpretations contained herein.
Coronal Emission Measures and Abundances for Moderately Active K Dwarfs Observed by Chandra

We have used Chandra to resolve the nearby 70 Oph (K0 V+K5 V) and 36 Oph (K1 V+K1 V) binary systems for the first time in X-rays. The LETG/HRC-S spectra of all four of these stars are presented and compared with an archival LETG spectrum of another moderately active K dwarf, Eri. Coronal densities are estimated from O VII line ratios and emission measure distributions are computed for all five of these stars. We see no substantial differences in coronal density or temperature among these stars, which is not surprising considering that they are all early K dwarfs with similar activity levels. However, we do see significant differences in coronal abundance patterns. Coronal abundance anomalies are generally associated with the first ionization potential (FIP) of the elements. On the Sun, low-FIP elements are enhanced in the corona relative to high-FIP elements, the so-called FIP effect. Different levels of FIP effect are seen for our stellar sample, ranging from 70 Oph A, which shows a prominent solar-like FIP effect, to 70 Oph B, which has no FIP bias at all or possibly even a weak inverse FIP effect. The strong abundance difference exhibited by the two 70 Oph stars is unexpected considering how similar these stars are in all other respects (spectral type, age, rotation period, X-ray flux). It will be difficult for any theoretical explanation for the FIP effect to explain how two stars so similar in all other respects can have coronae with different degrees of FIP bias. Finally, for the stars in our sample exhibiting a FIP effect, a curious difference from the solar version of the phenomenon is that the data seem to be more consistent with the high-FIP elements being depleted in the corona rather than with a low-FIP enhancement.
Massive tracheal necrosis complicating endotracheal intubation.

There are significant complications associated with endotracheal intubation. Massive tracheal necrosis secondary to tracheoesophageal space abscess developed in a 71-year-old man during mechanical ventilation. Elevated endotracheal tube cuff pressures, sepsis, hypotension, and other risk factors predispose to this disastrous consequence. (Chest 1989; 95:459-60)