cssi/SciSciGPT-SciSciNet huggingface dataset:
Intermittency analyses on the SIERRA measurements of the electric field fluctuations in the auroral zone

[1] We perform intermittency analyses on the electric field data obtained by the SIERRA sounding rocket in the auroral zone. The electric field fluctuations are broadband, covering the extremely low-frequency range with a power-law relation, similar to the type of fluctuations commonly observed at various altitudes of the auroral region. Our preliminary analyses of the data based on the technique of probability distribution functions indicate that the electric field fluctuations are intermittent in the spacecraft frame. Using the methods of wavelet analyses and local intermittency measures, we determine the degree of intermittency of the fluctuations at various scales. It is found that the electric field fluctuations are more intermittent at smaller scales.
Experimental Shock-Wave Interference Heating on a Cylinder at Mach 6 and 8

This paper presents the details of an experimental study of shock-wave interference heating on a cylindrical leading edge representative of the cowl of a rectangular hypersonic engine inlet. The study, which was conducted at Mach numbers of 6.3, 6.5, and 8.0, has provided 1) detailed pressure and heat-transfer-rate distributions for a two-dimensional shock-wave interference on a cylinder and 2) insight into the effects of temperature-d ependent specific heats on the phenomena. The peak pressure and heat-transfer rates were 2-25 times the undisturbed flow stagnation-point levels. The peak levels and their gradients increased with Mach number. Variation in specific heats and, hence, in the ratio of specific heats with temperature is manifested in slightly lower loads and amplification factors than for corresponding perfect-gas conditions.
Role of Helicobacter pylori in gastric carcinogenesis

Peptic ulcers and gastric malignancies are the two major complication of the course of Helicobacter pylori-associated chronic gastritis. Both gastric adenocarcinomas and MALT lymphomas occur in association with H pylori infection, and studies support an etiological association. This article discusses the natural history of H pylori-related gastric carcinogenesis and criteria to identify people susceptible to H pylori infection-associated gastric cancer. It then reviews the molecular and genetic mechanisms underlying the malignant transformation of the gastric mucosa associated with H pylori.
Catalytic acceptorless dehydrogenations: Ru-Macho catalyzed construction of amides and imines.

A commercially available ruthenium(II) PNP type pincer catalyst (Ru-Macho) promotes formation of amides and imines from alcohols and amines via an acceptorless dehydrogenation pathway. The formation of secondary amides, tertiary amides, and secondary ketimines occurs in yields ranging from 35% to 95%.
Team Performance with Test Scores

Team performance is a ubiquitous area of inquiry in the social sciences, and it motivates the problem of team selection -- choosing the members of a team for maximum performance. Influential work of Hong and Page has argued that testing individuals in isolation and then assembling the highest-scoring ones into a team is not an effective method for team selection. For a broad class of performance measures, based on the expected maximum of random variables representing individual candidates, we show that tests directly measuring individual performance are indeed ineffective, but that a more subtle family of tests used in isolation can provide a constant-factor approximation for team performance. These new tests measure the "potential" of individuals, in a precise sense, rather than performance; to our knowledge they represent the first time that individual tests have been shown to produce near-optimal teams for a non-trivial team performance measure. We also show families of subdmodular and supermodular team performance functions for which no test applied to individuals can produce near-optimal teams, and discuss implications for submodular maximization via hill-climbing.
Heuristic viewpoint concerning the thermal ambience relative to an accelerated frame

A linear wave field in its Minkowski ground state is analyzed heuristically by two observers, one inertial, the other accelerating in a linear and uniform way. Relative to the accelerated observer, the zero-point oscillations of each Minkowski plane wave mode have an unusual Fourier spectrum. Its intensity is (i) the same for all plane wave modes, (ii) isotropic, and (iii) that of a thermal ambience (relative to the accelerated frame). The temperature of this ambience is given by the Davies-Unruh formula kT=(ħ/2π)(g/c). The existence of this ambience is incompatible with the requirement that the laws of nature be formulated in terms of tensors.
Olefin cross-metathesis reactions at room temperature using the nonionic amphiphile "PTS": just add water.

The first examples of unsymmetrical olefin cross-metathesis reactions in water, involving water-insoluble substrates, at room temperature and using commercially available catalysts are reported. The key to success is to include small percentages of the nonionic, vitamin E-based amphiphile “PTS”. The nanometer micelles formed accommodate water-insoluble substrates, along with a readily available Ru-based metathesis catalyst. Reactions proceed at ambient temperatures with high efficiency and very high E-selectivity, and products are easily isolated.
Real normalized differentials and Arbarello’s conjecture

Using meromorphic differentials with real periods, we prove Arbarello’s conjecture that any compact complex cycle of dimension g - n in the moduli space Mg of smooth algebraic curves of genus g must intersect the locus of curves having a Weierstrass point of order at most n.
On First and Second Order Planar Elliptic Equations with Degeneracies

This paper deals with elliptic equations in the plane with degen- eracies. The equations are generated by a complex vector field that is elliptic everywhere except along a simple closed curve. Kernels for these equations are constructed. Properties of solutions, in a neighborhood of the degen- eracy curve, are obtained through integral and series representations. An application to a second order elliptic equation with a punctual singularity is given.
Thin-layer fracture density

Vertically propagating shear waves reflected from a thin reservoir permeated by a single oriented system of open vertical fractures contain information about the fracture density. The outer perimeter of the hodogram constructed from shear waves polarized in the fast and slow directions in the natural coordinate system is approximately elliptical. The polarization is defined as the angle which the major axis of the ellipse makes with the natural coordinate. Over a range of layer thickness which extends well above and below the tuning frequency, the polarization does not deviate from its value for an infinitely thick layer, ψ=tan-1R2/R1, by more than a few degrees. R1 and R2 are the reflection coefficients in the fast and slow directions. R1 is independent of the fracture density, but ψ, R2, and the anisotropy η all depend on the fracture density. R1, R2, and η are related by [R1+(1+2/η)][R2-(1+2/η)]=1-(1+2/η)2. Analysis of the constant‐anisotropy hyperbolas derived from this equation reveals conditions und...
The Economics of Online Postsecondary Education: MOOCs, Nonselective Education, and Highly Selective Education

Abstract I consider economically sustainable online postsecondary education, including massive open online courses (MOOCs). The analysis suggests that MOOCs will be financially sustainable substitutes for some non-selective postsecondary education, but there are substantial risks. The analysis suggests that MOOCs will be financially sustainable substitutes for only a small share of highly selective postsecondary education (HSPE) and are likely to collapse the economic model that allows HSPE institutions to invest in advanced education and research. I outline a non-MOOC model of online education that may allow HSPE institutions to sustain their distinctive activities and to reach a larger number of students.
XML Restructuring and Integration for Tabular Data

We study the data integration and restructuring issues of tabular data. We consider the case where the same set of data is collected from independent sites, stored in different DBMSs or other repositories, organized in different tabular or equivalent semi-structured formats, and published on the web. These sites transform tabular data into XML data with possible syntactic discrepancies in their original tabular structures. Data integration refers to the task of creating an integrated XML view with a pre-specified format by restructuring and integrating different XML documents. Existing XML query algebras are not sufficient for tabular conversions. We propose the XML-T model and the restructuring and integration operators for tabular data. We show with examples the uses of our operators to create “views".
Ferrocene‐Based Planar Chiral Imidazopyridinium Salts for Catalysis

Planar chirality remains an underutilized control element in asymmetric catalysis. Factors that have limited its broader application in catalysis include poor catalyst performance and difficulties associated with the economical production of enantiopure planar chiral compounds. The construction of planar chiral azolium salts that incorporate a sterically demanding iron sandwich complex is now reported. Applications of this new N-heterocyclic carbene as both an organocatalyst and a ligand for transition-metal catalysis demonstrate its unprecedented versatility and potential broad utility in asymmetric catalysis.
Nutational damping times in solids of revolution

We derive the characteristic nutational damping time T d for a linear, anelastic ellipsoid of revolution. Our calculation is based on the well-known idea that energy loss within an isolated spinning body causes the axis of maximum inertia of the body to align with its angular momentum vector, leading to pure spin. Energy loss occurs within an anelastic material whenever internal stresses are time variable; thus even freely rotating bodies in space, if they are wobbling, lose energy because internal stresses are associated with the accelerations caused by nutation. We find that T d = D(h)(μQ/ρa 2 Ω 3 ), where D(h) is a constant of the order of a few times 10 2 that depends on the shape of the body with h being the (aspect) ratio of the lengths of axes to one another, 11 is the elastic modulus, Q is a quality factor that describes the anelasticity of the material, p is the density of the body, a is its radius and Ω is an angular velocity. This functional form of the damping time is consistent with previous results but is more soundly based. Coefficients in past expressions vary between various authors, leading to predicted damping times that can differ by factors of the order of 10. To estimate damping times for typical asteroids, we choose values for the various parameters in this expression. We conclude that the extent of energy dissipation was over, rather than underestimated, in previous treatments. None the less, we argue that asteroids will generally be found in pure rotation, unless objects are small, spinning slowly and recently excited.
Fabrication of Potassium Titanyl Phosphate Films by Pulsed Excimer Laser Ablation for Nonlinear Optical Application

We have fabricated highly-orientated crystalline potassium titanyl phosphate (KTP) films on a variety of substrates by pulsed excimer laser ablation. The resulting films have been extensively characterized in terms of their compositional, crystalline, and optical properties. Nonlinear optical property of secondary harmonic generation of the films has been evaluated with a high d value comparable to that of KTP bulk crystals. The results are encouraging that the KTP films deposited are very promising for nonlinear optical waveguide device applications.
AN ALGORITHM FOR SOLVING THE SYSTEM-LEVEL PROBLEM IN MULTILEVEL OPTIMIZATION

A multilevel optimization approach which is applicable to nonhierarchic coupled systems is presented. The approach includes a general treatment of design (or behavior) constraints and coupling constraints at the discipline level through the use of norms. Three different types of norms are examined--the max norm, the Kreisselmeier-Steinhauser (KS) norm, and the 1_p norm. The max norm is recommended. The approach is demonstrated on a class of hub frame structures which simulate multidisciplinary systems. The max norm is shown to produce system-level constraint functions which are non-smooth. A cutting-plane algorithm is presented which adequately deals with the resulting corners in the constraint functions. The algorithm is tested on hub frames with increasing number of members (which simulate disciplines), and the results are summarized.
One Chance in a Million: Altruism and the Bone Marrow Registry

Stem cell transplants save lives of many patients with blood diseases. Donation is painful, but rarely has lasting adverse effects. Patients can accept transplants only from donors with compatible immune systems. Those lacking a sibling match must seek donations from the general population. The probability that two unrelated persons are compatible is less than 1/10,000. Health authorities maintain a registry of several million genetically tested potential donors who agree to donate if asked. We find that the benefits of adding registrants of every race exceed costs. We also explore the peculiar structure of voluntary public good provision that faces potential donors. (JEL D64, H41, I11) AQ 1
Monitoring Process Variability for Stationary Process Data

Processes that arise naturally, for example, from manufacturing or the environment, often exhibit complicated autocorrelation structures. When monitoring such a process for changes in variance, accounting for that structure is critical. While charts for monitoring the variance of processes of independent observations and some specific autocorrelated processes have been proposed in the past, the chart presented in this article can handle a general stationary process. The performance of the proposed chart was examined through simulations for the first-order autoregressive and first-order autoregressive-moving average processes and demonstrated with examples. Copyright © 2014 John Wiley & Sons, Ltd.
Organization and features of the Michigan terminal system

This paper will explore some aspects of the Michigan Terminal System (MTS) developed at the University of Michigan. MTS is the operating system used on the IBM 360/67 at the University of Michigan Computing Center, as well as at several other installations. It supports a large variety of uses ranging from very small student-type jobs to large jobs requiring several million bytes of storage and hours of processor time. Currently at the University of Michigan there are about 13,000 users running as many as 86,000 jobs per month.
Production of a cold atomic vapor using diode-laser cooling

We have used the light from diode lasers (λ = 852 nm) to damp the motion of atoms in a cesium vapor. We have been able to contain more than 107 atoms for 0.2 sec and cool them to a temperature of 100−30+100μK in this viscous photon medium (the so-called optical molasses).
The Pacific Center of Action of the Northern Hemisphere Annular Mode: Real or Artifact?

The leading empirical orthogonal function (EOF) of the sea level pressure (SLP) field, referred to as the Arctic Oscillation (AO) or Northern Hemisphere annular mode (NAM), consists of a dipole between the polar cap region and the surrounding zonal ring centered along 458N. Embedded within the outer ring are centers of action over the Euro-Atlantic and Pacific sectors in which SLP fluctuates in phase. That the observed SLP fluctuations at these two centers of action are virtually uncorrelated raises the question of whether the Pacific center in the annular mode could be an artifact of EOF analysis. It is argued that sea level pressure fluctuations at the Pacific and Euro-Atlantic centers of action of the AO/ NAM would be more strongly correlated were it not for the fact that SLP variability over the North Pacific is dominated by a pattern in which fluctuations over the North Atlantic and North Pacific are inversely related. Evidence of the coexistence of such a pattern, which resembles an augmented version of the Pacific‐North American pattern, is presented.
Journeys through antigravity

A possibility of journeys through antigravity has recently been proposed, with the suggestion that Weyl-invariant extension of scalars coupled to Einstein gravity allows for an unambiguous classical evolution through cosmological singularities in anisotropic spacetimes. We compute the Weyl invariant curvature squared and find that it blows up for the proposed anisotropic solution both at the Big Crunch as well as at the Big Bang. Therefore the cosmological singularities are not resolved by uplifting Einstein theory to a Weyl invariant model.
SEIFERT SURFACES, COMMUTATORS AND VASSILIEV INVARIANTS

We show that the Vassiliev invariants of a knot K, are obstructions to finding a regular Seifert surface, S, whose complement looks "simple" (e.g. like the complement of a disc) to the lower central series of its fundamental group. We also conjecture a characterization of knots whose invariants of all orders vanish in terms of their Seifert surfaces.
The trellis complexity of convolutional codes

Convolutional codes have a natural, regular, trellis structure that facilitates the implementation of Viterbi's algorithm. Linear block codes also have a natural, though not in general a regular, "minimal" trellis structure, which allows them to be decoded with a Viterbi-like algorithm. In both cases, the complexity of an unenhanced Viterbi decoding algorithm can be accurately estimated by the number of trellis edge symbols per encoded bit. It would therefore appear that we are in a good position to make a fair comparison of the Viterbi decoding complexity of block and convolutional codes. Unfortunately, however, this comparison is somewhat muddled by the fact that some convolutional codes, the punctured convolutional codes, are known to have trellis representations which are significantly less complex than the conventional trellis. In other words, the conventional trellis representation for a convolutional code may not be the "minimal" trellis representation. Thus ironically, we seem to know more about the minimal trellis representation for block than for convolutional codes. We provide a remedy, by developing a theory of minimal trellises for convolutional codes. This allows us to make a direct performance-complexity comparison for block and convolutional codes. A by-product of our work is an algorithm for choosing, from among all generator matrices for a given convolutional code, what we call a trellis-canonical generator matrix, from which the minimal trellis for the code can be directly constructed. Another by-product is that in the new theory, punctured convolutional codes no longer appear as a special class, but simply as high-rate convolutional codes whose trellis complexity is unexpectedly small.
Measurement of Oil Film Thickness for Application to Elastomeric Stirling Engine Rod Seals

The rod seal in the Stirling engine has the function of separating high pressure gas from low or ambient pressure oil. An experimental apparatus was designed to measure the oil film thickness distribution for an elastomeric seal in a reciprocating application. Tests were conducted on commercial elastomeric seals having a 76 mm rod and a 3.8 mm axial width. Test conditions included 70 and 90 seal durometers, a sliding velocity of 0.8 m/sec, and a zero pressure gradient across the seal. An acrylic cylinder and a typical synthetic base automotive lubricant were used. The experimental results showed that the effect of seal hardness on the oil film thickness is considerable. A comparison between analytical and experimental oil film profiles for an elastomeric seal during relatively high speed reciprocating motion showed an overall qualitative agreement.
Optically reconfigured active phased array antennas

An outline is presented of a study on the impact of active-module failure on the radiation pattern of phased array antennas. A linear phased array composed of 13 active elements was simulated. The interactive simulation program was based on the calculation of array factor by specifying each elements amplitude, phase, spacing and radiation pattern. Results of the simulation predict increases in the sidelobe level associated with reduction in the directivity gain. Degradation on the array factor is also more substantial on the elements closer to the center. For two symmetric elements a similar degradation was observed. As the radiating beam was scanned, asymmetric radiation patterns were predicted for the failed mode of operation. The effects of change in the radiating frequency on the radiation pattern was studied for normal and failure modes of operation. To study the effect of unequal interelement spacing on the radiation pattern under failure modes a linear progression of array spacing was introduced to the 13-element array. Results of this simulation for normal and failure modes of operation are also discussed. >
Explosive quark matter and the "Centauro" event

We study the hypothesis that the "Centauro" event found by the Brazil-Japan cosmic-ray emulsion collaboration is initiated by the explosion of a metastable glob of highly compressed hadronic matter present in the primary spectrum. A crude liquid-drop model is formulated to investigate the properties of the equation of state necessary to support such a hypothesis. The evolution of such a glob as it moves through the atmosphere and eventually explodes is described. Two other variants are also discussed: one is that the glob contains an unconfined, massive quark, while the other is that the lowest-mass fractionally charged hadron has large baryon number. In that case, the Centauro event consists of fragmentation of a nucleon primary into such objects. The most prominent experimental consequences of our speculations appear to be the existence of peculiar explosive events at high altitudes at a rate \ensuremath{\lesssim}${10}^{3}$ ${\mathrm{m}}^{\ensuremath{-}2}$${\mathrm{yr}}^{\ensuremath{-}1}$, and/or penetrating particles of high ionization density at sea level containing fractional charge.
An asymptotic theory of wind-tunnel-wall interference on subsonic slender bodies

An asymptotic theory of solid cylindrical wind-tunnel-wall interference about subsonic slender bodies has been developed. The basic approximation used is one of large wall-radius to body-length ratio. Matched asymptotic expansions show that in contrast to the analogous two-dimensional problem of a confined airfoil, three regions exist. Besides the incompressible crossflow and nearly axisymmetric zones, a wall layer exists where reflection in the wall of the line source representing the body becomes of dominant importance. From the theory, the interference pressures are shown to be approximately constant for closed bodies. Also demonstrated is that D'Alembert's paradox holds for interference drag of such shapes. Numerical studies comparing the exact theory to the asymptotic model which provides drastic simplifications, show that the latter can be used with reasonable accuracy to describe flows, even where the characteristic tunnel-radius to body-length ratio is as low as 1.5.
Existence of extremal metrics on almost homogeneous manifolds of cohomogeneity one—II

We consider the existence of Calabi extremal metrics on certain compact almost homogeneous manifold of cohomogeneity one. We proved that the positivity of the generalized Futaki invariant implies the existence. We expect that the converse is also true for all this kind of manifolds.
Bidding Behavior in Descending and Ascending Auctions

This research examines how individual differences and institutional practices influence consumer bidding in auctions. Bidders may be motivated by different goals, e.g., thrill (of winning the item, with minimal attention to what they pay for it) versus prudence (winning the item at a price at or below its perceived value). Also, innate or auctioneer-induced differences may exist in the precision and salience of bidder cognitions about the item's value. We report two studies on how these motivational and cognitive factors influence bids in descending and ascending auctions, respectively. Each study also manipulated a situational variable (wait time at each price step). The two auctions realized different average prices for the same item set. Average bids were higher in the descending (versus ascending) auction in several study conditions. In both auction formats, bidders primed with thrill (versus prudence) bid higher, but more precise and/or salient values attenuated this goal effect. Among other results, in the descending auction, longer wait times elicited higher bids from bidders primed with thrill (but not prudence). In the ascending auction, longer wait times produced lower bids for bidders primed with prudence (but not thrill). These findings on consumer bidding behavior have practical implications for auction design.
Politicians and banks: Political influences on government-owned banks in emerging markets☆

Abstract Government ownership of banks is very common in countries other than the United States. This paper provides cross-country, bank-level empirical evidence about political influences on these banks. It shows that government-owned banks increase their lending in election years relative to private banks. This effect is robust to controlling for country-specific macroeconomic and institutional factors as well as bank-specific factors. The increase in lending is about 11% of a government-owned bank's total loan portfolio or about 0.5% of the median country's GDP per election per government-owned bank.
Cumulant-based blind optimum beamforming

Sensor response, location uncertainty, and use of sample statistics can severely degrade the performance of optimum beamformers. We propose blind estimation of the source steering vector in the presence of multiple, directional, correlated or coherent Gaussian interferers via higher order statistics. In this way, we employ the statistical characteristics of the desired signal to make the necessary discrimination, without any a-priori knowledge of array manifold and direction-of-arrival (DOA) information about the desired signal. We then improve our method to utilize the data in a more efficient manner. In any application, only sample statistics are available, so we propose a robust beamforming approach that employs the steering vector estimate obtained by cumulant-based signal processing. We further propose a method that employs both covariance and cumulant information to combat finite sample effects. We analyze the effects of multipath propagation on the reception of the desired signal. We show that even in the presence of coherence, cumulant-based beamformer still behaves as the optimum beamformer that maximizes the signal-to-interference-plus-noise ratio (SINR). Finally, we propose an adaptive version of our algorithm simulations demonstrate the excellent performance of our approach in a wide variety of situations. >
Much ado about functions

This paper surveys basic results on complexity classes of partial multivalued functions. We stress basic inclusion relations, interesting hierarchies, and results that demonstrate that hierarchies are extant.
The Gender and Generational Consequences of the Demographic Transition and Population Policy: An Assessment of the Micro and Macro Linkages

The demographic transition changes the age composition of a population, affecting resource allocations at the household and aggregate level. If age profiles of income, consumption, savings and investments were stable and estimable for the entire population, they might suggest how the demographic transition would affects inputs to growth. However, existing macro and micro simulations are estimated from unrepresentative samples of wage earners that do not distinguish sex, schooling, etc. The “demographic dividend” is better evaluated through case studies of household surveys and long-run social experiments. Matlab, Bangladesh, extended a family planning and maternal and child health program to half the villages in its district in 1977, and recorded fertility in the program villages was 16 percent lower than in control villages for the following two decades until 1996. Households in program villages realized health and productivity gains that were concentrated among women, while child survival and schooling increased, and household physical assets were 25 percent greater per adult than in control villages.
A compositional query algebra for second-order logic and uncertain databases

World-set algebra is a variable-free query language for uncertain databases. It constitutes the core of the query language implemented in MayBMS, an uncertain database system. This paper shows that world-set algebra captures exactly second-order logic over finite structures, or equivalently, the polynomial hierarchy. The proofs also imply that world-set algebra is closed under composition, a previously open problem.
The Child Adoption Marketplace Parental Preferences and Adoption Outcomes

In the United States, child adoption costs vary considerably, ranging from no out-of-pocket expense to US$50,000 or more. What are the causes for the variability in adoption expenses? We administered a survey to a sample of Michigan adoptive families to link adoptive parent characteristics, child characteristics, and adoption-related expenses and subsidies. We then estimated “hedonic” regressions in which adoption cost is a function of child characteristics. The analysis shows that up to 74 percent of the variation in adoption costs is explained by child characteristics. In particular, costs are lower for older children, children of African descent, and special needs children. Findings inform policies regarding the transition of children from foster care to adoptive families.
Neural correlates of segmental and tonal information in speech perception

The Chinese language provides an optimal window for investigating both segmental and suprasegmental units. The aim of this cross-linguistic fMRI study is to elucidate neural mechanisms involved in extraction of Chinese consonants, rhymes, and tones from syllable pairs that are distinguished by only one phonetic feature (minimal) vs. those that are distinguished by two or more phonetic features (non-minimal). Triplets of Chinese monosyllables were constructed for three tasks comparing consonants, rhymes, and tones. Each triplet consisted of two target syllables with an intervening distracter. Ten Chinese and English subjects were asked to selectively attend to targeted sub-syllabic components and make same-different judgments. Direct between-group comparisons in both minimal and non-minimal pairs reveal increased activation for the Chinese group in predominantly left-sided frontal, parietal, and temporal regions. Within-group comparisons of non-minimal and minimal pairs show that frontal and parietal activity varies for each sub-syllabic component. In the frontal lobe, the Chinese group shows bilateral activation of the anterior middle frontal gyrus (MFG) for rhymes and tones only. Within-group comparisons of consonants, rhymes, and tones show that rhymes induce greater activation in the left posterior MFG for the Chinese group when compared to consonants and tones in non-minimal pairs. These findings collectively support the notion of a widely distributed cortical network underlying different aspects of phonological processing. This neural network is sensitive to the phonological structure of a listener's native language. Hum. Brain Mapping 20:185-200, 2003.
An Empirical Analysis of the Effects of Online Trading on Stock Price and Trading Volume Reactions to Earnings Announcements

This study provides evidence regarding the effects of online trading on stock price and trading volume reactions to quarterly earnings announcements. We test for differences in stock price and volume reactions to quarterly earnings announcements between a period with a significant amount of online trading (1996-99) and a period without online trading (1992-95). We conjecture that online trading has increased the proportion of naive investors in the market. We predict that this will result in (1) a decrease in the average precision of investor information prior to earnings announcements leading to higher earnings response coefficients (ERCs), (2) an increase in differential interpretation of earnings leading to higher trading volume reactions that are unrelated to price change, and (3) a decrease in differential prior precision leading to a decrease in the association between trading volume and absolute price change. We find evidence consistent with all three predictions. Our findings are relevant for assessing the validity of concerns about online trading expressed by regulators and the validity of theoretical models of trade with asymmetrically informed investors.
Constitution or Conflict

Constitutional resolution of disputes between constituent groups of a polity avoids the incremental costs of civil conflict. But, the political process prescribed by a constitution provides a viable alternative to civil conflict only if the constitution is self-enforcing. Theoretical analysis reveals that the following properties help to make it possible to design a self-enforcing constitution that can settle recurring disputes: No party to the disputes has a big advantage in civil conflict. The parties to the disputes expect the incremental costs of civil conflict to be large relative to the importance of the disputes that arise between them. The parties are greatly concerned about the future consequences of their current actions. Theoretical analysis also reveals that a self-enforcing constitution can require limitations on the prerogatives of winners of constitutional contests such that on average outcomes under the constitution are not too favorable to any one party and such that the outcome of each c...
Using Power Laws to Estimate Conflict Size

Casualty counts are often controversial, and thorough research can only go so far in resolving such debates—there will almost always be missing data, and thus, a need to draw inferences about how comprehensively violence has been recorded. This article addresses that challenge by developing an estimation strategy based on the observation that violent events are generally distributed according to power laws, a pattern that structures expectations about what event data on armed conflict would look like if those data were complete. This technique is applied to estimate the number of Native American and US casualties in the American Indian Wars between 1776 and 1890, demonstrating how scholars can use power laws to estimate conflict size, even (and perhaps especially) where previous literature has been unable to do so.
Nonlinear state feedback synthesis by global input/output linearization

This paper studies the design of feedback controllers for trajectory tracking in single-input/ single-output nonlinear systems x = f(x) + g(x) u, y = h(x). A nonlinear transformation of the form v = k(x) + λ(x) u that transforms this nonlinear input/output system into a linear system is first constructed. On the basis of this transformation, an approach for designing control laws for trajectory tracking is presented. The control law is robust in the sense that small changes in it do not produce large steady state errors or loss of stability. The theory provides a unified framework for treating control problems arising in nonlinear chemical processes; this is illustrated by a batch reactor control example.
Catalytic Intermolecular Linear Allylic C−H Amination via Heterobimetallic Catalysis

A novel heterobimetallic Pd(II)sulfoxide/(salen)Cr(III)Cl-catalyzed intermolecular linear allylic C−H amination (LAA) is reported. This reaction directly converts densely functionalized α-olefin substrates (1 equiv) to linear (E)-allylic carbamates with good yields and outstanding regio- and stereoselectivities (>20:1). Chiral bis-homoallylic and homoallylic oxygen, nitrogen, and carbon substituted α-olefins undergo allylic C−H amination with good yields, excellent selectivities, and no erosion in enantiomeric purity. Streamlined routes to (E)-allylic carbamates that can be further elaborated to medicinally and biologically relevant allylic amines are also demonstrated. Valuable 15N-labeled allylic amines may be generated directly from allyl moieties at late stages of synthetic routes by using the readily available 15N-(methoxycarbonyl)-p-toluenesulfonamide nucleophile. Evidence is provided that this reaction proceeds via a heterobimetallic mechanism where Pd/sulfoxide mediates allylic C−H cleavage to for...
Global MHD Simulation of the Inner Accretion Disk in a Pseudo-Newtonian Potential

We present a detailed three-dimensional magnetohydrodynamic (MHD) simulation describing the inner region of a disk accreting onto a black hole. To avoid the technical complications of general relativity, the dynamics are treated in Newtonian fashion using the pseudo-Newtonian Paczynski-Wiita potential. The disk evolves as a result of angular momentum transport that is produced naturally from MHD turbulence generated by the magnetorotational instability. We find that the resulting stress is continuous across the marginally stable orbit, in contradiction to the widely held assumption that the stress should go to zero there. As a consequence, the specific angular momentum of the matter accreted into the hole is smaller than the specific angular momentum at the marginally stable orbit. The disk exhibits large fluctuations in almost every quantity, both spatially and temporally. In particular, the ratio of stress to pressure (the local analog of the Shakura-Sunyaev α parameter) exhibits both systematic gradients and large fluctuations; from ~10-2 in the disk midplane at large radius, it rises to ~10 both at a few gas density scale heights above the plane at large radius and near the midplane well inside the plunging region. Driven in part by large-amplitude waves excited near the marginally stable orbit, both the mass accretion rate and the integrated stress exhibit large fluctuations whose Fourier power spectra are smooth "red" power laws stretching over several orders of magnitude in timescale.
GaN-Based High Temperature and Radiation-Hard Electronics for Harsh Environments

We develop novel GaN-based high temperature and radiation-hard electronics to realize data acquisition electronics and transmitters suitable for operations in harsh planetary environments. In this paper, we discuss our research on metal-oxide-semiconductor (MOS) transistors that are targeted for 500 (sup o)C operation and >2 Mrad radiation hardness. For the target device performance, we develop Schottky-free AlGaN/GaN MOS transistors, where a gate electrode is processed in a MOS layout using an Al2O3 gate dielectric layer....
A geometric Littlewood-Richardson rule

We describe a geometric Littlewood-Richardson rule, interpreted as deforming the intersection of two Schubert varieties into the union of Schubert varieties. There are no restrictions on the base eld, and all multiplicities arising are 1; this is important for applications. This rule should be seen as a generalization of Pieri’s rule to arbitrary Schubert classes, by way of explicit homotopies. It has straightforward bijections to other Littlewood-Richardson rules, such as tableaux, and Knutson and Tao’s puzzles. This gives the rst geometric proof and interpretation of the Littlewood-Richardson rule. Geometric consequences are described here and in [V2], [KV1], [KV2], [V3]. For example, the rule also has an interpretation in K-theory, suggested by Buch, which gives an extension of puzzles to K-theory.
Jeans instability in a tidally disrupted halo satellite galaxy

We use a hybrid test particle/N-body simulation to integrate 4 million massless test particle trajectories within a fully self-consistent 10 5 particle N-body simulation. The number of massless particles allows us to resolve ne structure in the spatial distribution and phase space of a dwarf galaxy as it is disrupted in the tidal eld of a Milky Way type galaxy. The tidal tails exhibit nearly periodic clumping or a smoke-like appearance. By running simulations with dierent satellite particle mass, halo particle mass, number of massive and massless particles and with and without a galaxy disk, we have determined that the instabilities are not due to numerical noise, amplication of structure in the halo, or shocking as the satellite passes through the disk of the Galaxy. We measure Jeans wavelengths and growth timescales in the tidal tail and show that the Jeans instability is a viable explanation for the clumps. We nd that the instability causes velocity perturbations of order 10 km/s. Clumps in tidal tails present in the Milky Way could be seen in stellar radial velocity surveys as well as number counts. We nd that the unstable wavelength growth is sensitive to the simulated mass of dark matter halo particles. A simulation with a smoother halo exhibits colder and thinner tidal tails with more closely spaced clumps than a simulation with more massive dark matter halo particles. Heating by the halo particles increases the Jeans wavelength in the tidal tail aecting substructure development, suggesting an intricate connection between tidal tails and dark matter halo substructure.
Effect of stitching on the strength of bonded composite single lap joints

An experimental investigation has been conducted to determine the effect of stitching on the static and fatigue failure load of bonded composite single lap joints. The variables considered in the static tests included adherend thickness, overlap length, stitch spacing, and number of rows of stitches. A limited fatigue program was conducted for one configuration to compare the fatigue life of stitched and unstitched joints. Up to a 38 percent improvement in static failure load and an order of magnitude increase in fatigue life compared with unstiffened results are obtained by a single row of stitches near the end of the overlap. Additional rows of stitching or different stitch spacing has little effect on static joint failure load. Thicker adherends and larger overlap length result in larger improvements in static failure load with stitching. Further research is needed to refine the stitching process in order to obtain the maximum improvements in joint failure load.
Interpreting sustainability in economic terms: dynamic efficiency plus intergenerational equity

Abstract Economists have confined the concept of ‘sustainability’ to intertemporal distributional equity. We propose a broader definition, combining dynamic efficiency and intergenerational equity, and relate it to two concepts from neoclassical economics: potential Pareto-improvements and inter-personal compensation.
Goldstini Can Give the Higgs a Boost

Supersymmetric collider phenomenology depends crucially on whether the lightest observable-sector supersymmetric particle (LOSP) decays, and if so, what the LOSP decay products are. For instance, in SUSY models where the gravitino is lighter than the LOSP, the LOSP decays to its superpartner and a longitudinal gravitino via super- current couplings. In this paper, we show that LOSP decays can be substantially modied when there are multiple sectors that break supersymmetry, where in addition to the grav- itino there are light uneaten goldstini. As a particularly striking example, a bino-like LOSP can have a near 100% branching fraction to a higgs boson and an uneaten goldstino, even if the LOSP has negligible higgsino fraction. This occurs because the uneaten goldstino is unconstrained by the supercurrent, allowing additional operators to mediate LOSP decay. These operators can be enhanced in the presence of a U(1)R symmetry, leading to copious boosted higgs production in SUSY cascade decays.
SCALING LIMITS FOR BEAM WAVE PROPAGATION IN ATMOSPHERIC TURBULENCE

We prove the convergence of the solutions of the parabolic wave equation to that of the Gaussian white-noise model widely used in the physical literature. The random medium is isotropic and is assumed to have integrable correlation coefficient in the propagation direction. We discuss the limits of vanishing inner scale and divergent outer scale of the turbulent medium.
Deformation and Instability of Underthrusting Lithospheric Plates

Summary Recent confirmation of the relationship between seismology and tectonic plate movement has focused attention on the deformation and instability of lithospheric plates. In this paper models of the underthrusting litho-sphere for the calculation of displacement and deflection are constructed. The first of the three contributions is a mathematical theory that rigorously demonstrates the elastic instability in the descending lithosphere. The theory states that lithospheric thrust beneath island arcs becomes unstable and suffers deflection as the compression increases. Thus, in the neighbour-hood of the edges where the lithospheric plate plunges into the asthenosphere and mesosphere its shape will be contorted. The second contribution is the calculation of the lateral displacement. It is found that, before contortion, the plate will thicken and contract at different positions with the variation in thickness following a parabolic profile. Finally, the depth distribution and the origin of the intermediate and deep focus earthquakes are explained in terms of plate buckling and contortion.
Sacrificing a little coverage can substantially increase network lifetime

We present a simple, local protocol, pCover, which provides partial (but high) coverage in sensor networks. Through pCover, we demonstrate that it is feasible to maintain a high coverage (~90%) while significantly increasing coverage duration when compared with protocols that provide full coverage. In particular, we show that we are able to maintain 94% coverage for a duration that is 2.3-7 times the duration for which existing protocols maintain full coverage. Through simulations, we show that our protocol provides load balancing, i.e., the desired level of coverage is maintained (almost) until the point where all sensors deplete their batteries. We also show that pCover handles failure of sensors, different coverage areas, different node densities, and different topologies, and can be used for dynamically changing the level of coverage.
Estimating fatality reductions from increased safety belt use

Fatality reductions from increases in safety belt use are estimated taking into account that drivers who change from being nonusers to being users have lower accident involvement rates than the remaining nonusers, a process referred to as "selective recruitment." Analytical functions are derived which express expected fatality reductions in terms of changes in safety belt use rates from an initial rate. The function parameters are determined by requiring that computed average crash rates for nonusers be 53% higher than the rates for users, a recently determined empirical value. These functions show that, depending on the initial use rate and use rate increase, selective recruitment may increase or decrease expected fatality reductions. However, effects are relatively small, in no case exceeding +/- 5.3%.
Do Depositors Punish Banks for "Bad" Behavior?: Market Discipline, Deposit Insurance, and Banking Crises

This paper empirically investigates two issues largely unexplored by the literature on market discipline. We evaluate the interaction between market discipline and deposit insurance and the impact of banking crises on market discipline. We focus on the experiences of Argentina, Chile, and Mexico during the 1980s and 1990s. We find that depositors discipline banks by withdrawing deposits and by requiring higher interest rates. Deposit insurance does not appear to diminish the extent of market discipline. Aggregate shocks affect deposits and interest rates during crises, regardless of bank fundamentals, and investors' responsiveness to bank risk taking increases in the aftermath of crises.