cssi/SciSciGPT-SciSciNet huggingface dataset:
A generalized network formulation for aperture problems

A general formulation for aperture problems is given in terms of the method of moments. It applies to any two regions isolated except for coupling through the aperture. The aperture characteristics are expressed in terms of two aperture admittance matrices, one for each region. The admittance matrix for one region is independent of the other region, and hence can be used for any problem involving that region and aperture. The solution can be represented by two generalized n -port networks connected in parallel with current sources. The current sources are related to the tangential magnetic field which exists over the aperture region when the aperture is closed by an electric conductor. Formulas for fields (linear functionals) and power (quadratic functionals) are given in terms of the admittance matrices.
Acoustics of Eastern and Western bells, old and new

Bells have many modes of vibration whose modal shapes are characterized by the numbers of nodal meridians and nodal circles. In Western church bells and carillon bells, the bell is shaped so that the lowest mode frequencies are harmonically related. The subjective strike note is determined by three strong partial tones with frequencies nearly in the ratios 2: 3: 4. The pitch of a handbell, on the other hand, is determined by the frequency of the fundamental tone. In ancient Chinese bells, the vibrational modes occur in pairs, and two different tones result from striking at the sui and gu strike points. A new type of carillon bell has been developed in which the traditional minor third partial is replaced by a major third partial, thus changing the timbre of the bell.
A Simple Procedure to Evaluate Ex Ante Producer Welfare under Price Uncertainty

A simple procedure is proposed for evaluating producer welfare under price uncertainty. The method is derived under the assumption of constant absolute risk aversion in which risk preferences depend on the stock of wealth but not on the flow of income. Numerical examples corroborate the procedure's properties.
Balance, accountability, and responsiveness : lessons about decentralization

Decentralized fiscal structures are more suitable in developing countries than centralized structures are, especially when they are supported by strengthening the rule of law, an independent central bank, an independent judiciary, a charter of rights, appropriate limits on various levels of government, institutions for conflict resolution and for the evaluation of government efforts at all levels, and mechanisms (including a free media) for listening and making government accountable to the citizenry. Shah examines the reasons developing countries are reexamining the respective roles of the private sector, civil society, and various levels of government - and considering new fiscal arrangements between national and lower levels of government. Decentralization may be particularly well-suited to developing countries, where central governments are not as well developed as in industrial countries - because information requirements and transaction costs are lower at lower levels of government and the government can be more responsive and accountable to the citizenry. Vital to the success of decentralized decisionmaking, says Shah, are: -A broad public consensus that decentralization is appropriate. -Civil service reform designed to encourage a service orientation, to discourage command-and-control governance and rent-seeking, and to prevent the central government from have a direct say in the recruitment and promotion of subnational civil servants. -Proper monitoring and oversight of governance. Other lessons from experience: -When there is citizen participation and transparency in decisionmaking, limited budgeting, auditing, and accounting systems at the subnational level should not be considered a barrier to decentralization. Those technical capabilities can be borrowed from higher levels of government. -Indonesia and Pakistan provide good examples of assymmetric decentralization, in which various powers can be assigned to different levels of government, depending on capacity. -The delinking of taxing and spending decisions leads to lack of accountability in the public sector. -Revenue-sharing (tax by tax) distorts incentives for efficient tax collection. -Properly structured (simple, transparent, consistent with objectives) fiscal transfers can improve government accountability. Fiscal transfers can also be used to encourage competition for the supply of public goods. In Canada and Chile, for example, Catholic schools compete with public schools for financing. This paper - a product of the Country and Regional Evaluation Division, Operations Evaluation Department - is part of a larger effort in the department to learn lessons of evaluation in improving public sector performance in developing countries. The author may be contacted at ashah@worldbank.org.
Propulsive performance of biologically inspired flapping foils at high Reynolds numbers.

SUMMARY Propulsion and maneuvering underwater by flapping foil motion, optimized through years of evolution, is ubiquitous in nature, yet marine propulsors inspired by examples of highly maneuverable marine life or aquatic birds are not widely implemented in engineering. Performance data from flapping foils, moving in a rolling and pitching motion, are presented at high Reynolds numbers, Re= Uc/ ν, or O(10 4 ), where U is the relative inflow velocity, c is the chord length of the foil, and ν is the kinematic viscosity of the fluid, from water tunnel experiments using a foil actuator module designed after an aquatic penguin or turtle fin. The average thrust coefficients and efficiency measurements are recorded over a range of kinematic flapping amplitudes and frequencies. Results reveal a maximum thrust coefficient of 2.09, and for low values of angle of attack the thrust generally increases with Strouhal number, without much penalty to efficiency. Strouhal number is defined as St =2 h 0 f/U , where f is the frequency of flapping, and 2 h 0 is the peak-to-peak amplitude of flapping. The thrust and efficiency contour plots also present a useful performance trend where, at low angles of attack, high thrust and efficiency can be gained at sufficiently high Strouhal numbers. Understanding the motion of aquatic penguins and turtle wings and emulating these motions mechanically can yield insight into the hydrodynamics of how these animals swim and also improve performance of biologically inspired propulsive devices.
Selectivity in the TiO2- mediated photocatalytic oxidation of thioethers

The relative rates of photooxygenation of substituted diphenyl sulfides on irradiated TiO2 powders suspended in oxygenated acetonitrile correlate linearly with σ+, as is consistent with formation of a surface bound cation radical in the primary photoprocess. Substituted dibenzyl sulfides, in contrast, suffer C-S cleavage upon photocatalyzed oxidation. Factors disposing these reactions toward preferential sulfoxide formation or bond cleavage are discussed.
Approximation of stochastic partial differential equations by a kernel-based collocation method

In this paper we present the theoretical framework needed to justify the use of a kernel-based collocation method meshfree approximation method to estimate the solution of high-dimensional stochastic partial differential equations SPDEs. Using an implicit time-stepping scheme, we transform stochastic parabolic equations into stochastic elliptic equations. Our main attention is concentrated on the numerical solution of the elliptic equations at each time step. The estimator of the solution of the elliptic equations is given as a linear combination of reproducing kernels derived from the differential and boundary operators of the SPDE centred at collocation points to be chosen by the user. The random expansion coefficients are computed by solving a random system of linear equations. Numerical experiments demonstrate the feasibility of the method.
Conversions between metal–ligand multiple bond (MLMB) types: carbonyl olefination and other applications

In this Perspective, methods for the direct conversion of one type of metal–ligand multiple bond (MLMB) to another are discussed. Of particular interest, because of their potential utility in organic synthesis, are examples of direct conversion of N- and O-based MLMB to alkylidenes and alkylidynes. Recent efforts in this area from our laboratory with some background are detailed. The research from our group involves metallacycles prepared directly from an imido ligand where a metal–carbon bond can have alkylidene-like or alkyl-like properties and reactivity depending on the ancillary ligands.
Safe Screening with Variational Inequalities and Its Application to Lasso

Sparse learning techniques have been routinely used for feature selection as the resulting model usually has a small number of non-zero entries. Safe screening, which eliminates the features that are guaranteed to have zero coefficients for a certain value of the regularization parameter, is a technique for improving the computational efficiency. Safe screening is gaining increasing attention since 1) solving sparse learning formulations usually has a high computational cost especially when the number of features is large and 2) one needs to try several regularization parameters to select a suitable model. In this paper, we propose an approach called "Sasvi" (Safe screening with variational inequalities). Sasvi makes use of the variational inequality that provides the sufficient and necessary optimality condition for the dual problem. Several existing approaches for Lasso screening can be casted as relaxed versions of the proposed Sasvi, thus Sasvi provides a stronger safe screening rule. We further study the monotone properties of Sasvi for Lasso, based on which a sure removal regularization parameter can be identified for each feature. Experimental results on both synthetic and real data sets are reported to demonstrate the effectiveness of the proposed Sasvi for Lasso screening.
Numerical uncertainty at mesoscale in a Lagrangian model in complex terrain

Abstract. Recently, it has been shown that mass conservation in Lagrangian models is improved by using time-average winds out of Eulerian models. In this study, we evaluate the mass conservation and trajectory uncertainties in complex terrain at mesoscale using the FLEXPART Lagrangian particle dispersion model coupled with the WRF mesoscale model. The specific form of vertical wind used is found to have a large effect. Time average wind with time average sigma dot (σ · ), instantaneous wind with geometric cartesian vertical wind (w) and instantaneous wind with σ · are used to simulate mixing ratios of a passive tracer in forward and backward runs using different time interval outputs and horizontal resolutions in California. Mass conservation in the FLEXPART model was not an issue when using time-average wind or instantaneous wind with σ · . However, mass was poorly conserved using instantaneous wind with w, with a typical variation of 25% within 24 h. Uncertainties in surface residence time (a backtrajectory product commonly used in source receptor studies or inverse modeling) calculated for each backtrajectory run were also analyzed. The smallest uncertainties were systematically found when using time-average wind. Uncertainties using instantaneous wind with σ · were slightly larger, as long as the time interval of output was sufficiently small. The largest uncertainties were found when using instantaneous wind with w. Those uncertainties were found to be linearly correlated with the local average gradient of orography. Differences in uncertainty were much smaller when trajectories were calculated over flat terrain. For a typical run at mesoscale in complex terrain, 4 km horizontal resolution and 1 h time interval output, the average uncertainty and bias in surface residence time is, respectively, 8.4% and −2.5% using time-average wind, and 13% and −3.7% using instantaneous wind with σ · in complex terrain. The corresponding values for instantaneous wind with cartesian w were 24% and −11%. While the use of time-average wind systematically improves uncertainty in FLEXPART, the improvements are small, and therfore a systematic use of time-average wind in Lagrangian models is not necessarily required. Use of cartesian vertical wind in complex terrain, however, should be avoided.
How much GPS data do we need

Abstract With the rapid growth of communications technologies, GPS, and the mobile internet, an increasing amount of real-time location information is collected by private companies and could be marketed for retail. This body of data offers transportation agencies potential opportunities to improve operations, but it also presents unique challenges. This article investigates the question of how much GPS data is needed to power a traffic information system capable of providing accurate speed (and thus travel time) information. A hybrid data framework is proposed to use real-time, GPS-based, point-speed data from mobile sources to augment previous investments in existing fixed sensors. In addition, a systematic analysis of the performance trade-offs among a menu of data sources is described. The results presented in this article were generated from the first procurement of streaming probe data from the private sector conducted on behalf of the California Department of Transportation and executed by UC Berkeley. Third-party data were incorporated with loop detector data and travel times were estimated within the bounds of driver variability. This achievement was repeated over multiple weeks and multiple congested freeway sites. Our findings indicate that penetration rates for GPS-based probe data are now suitable for travel time estimation on selected corridors. Data fusion makes possible the effective use of data from multiple sources or providers; when data from multiple sources are fused, superior results are obtained. On a freeway that is already instrumented with loop detectors, better travel time performance may be achieved by fusing a relatively small amount of probe data than by doubling the number of loop detectors. Finally, the answer to how much GPS data is needed must address issues of data quality in terms of sample rate and penetration rate.
Temporal damping effect of the Yucca Mountain fractured unsaturated rock on transient infiltration pulses

Performance assessment of the Yucca Mountain unsaturated zone (UZ) as the site for an underground repository of high-level radioactive waste relies on the crucial assumption that water percolation processes in the unsaturated zone can be approximated as a steady-state condition. Justification of such an assumption is based on temporal damping effects of several geological units within the unsaturated tuff formation. In particular, the nonwelded tuff of the Painbrush Group (PTn unit) at Yucca Mountain, because of its highly porous physical properties, has been conceptualized to have a significant capacity for temporally damping transient percolation fluxes. The objective of this study is to investigate these damping effects, using a three-dimensional (3-D) mountain-scale model as well as several one-dimensional (1-D) models. The 3-D model incorporates a wide variety of the updated field data for the highly heterogeneous unsaturated formation at Yucca Mountain. The model is first run to steady state and calibrated using field-measured data and then transient pulse infiltrations are applied to the model top boundary. Subsequent changes in percolation fluxes at the bottom of and within the PTn unit are examined under episodic infiltration boundary conditions. The 1-D model is used to examine the long-term response of the flow system to higher infiltration pulses, while the damping effect is also investigated through modeling tracer transport in the UZ under episodic infiltration condition. Simulation results show the existence of damping effects within the PTn unit and also indicate that the assumption of steady-state flow conditions below the PTn unit is reasonable. However, the study also finds that some fast flow paths along faults exist, causing vertical-flux quick responses at the PTn bottom to the episodic infiltration at the top boundary.
Tile or Stare? Cadence and Sky-monitoring Observing Strategies That Maximize the Number of Discovered Transients

To maximize the number of transients discovered on the sky, should sky-monitoring projects stare at one location or continually jump from location to location, tiling the sky? If tiling is preferred, what cadence maximizes the discovery rate? As sky monitoring is a growing part of astronomical observing, utilized to find such phenomena as supernovae, microlensing, and planet transits, well-thought-out answers to these questions are increasingly important. Answers are sky-, source-, and telescope-dependent and should include information about the source luminosity distribution near the observation limit, the duration of variability, the nature of the dominant noise, and the magnitude of down and slew times. Usually, a critical slope of the effective cumulative transient apparent luminosity distribution (log N–log S) at the limiting magnitude will define when "tile" or "stare" is superior. For shallower slopes, when "tile" is superior, we discuss optimal cadences and pointing algorithms. For transients discovered on a single exposure or time-contiguous series of exposures, when down and slew times are small and the character of the noise is unchanged, the most productive cadence for isotropic power-law luminosity distributions is the duration of the transient—faster cadences waste time rediscovering known transients, while slower cadences neglect transients occurring in other fields. A "cadence creep" strategy might find an optimal discovery cadence experimentally when one is not uniquely predetermined theoretically. Guest investigator programs might diversify previously dedicated sky-monitoring telescopes by implementing bandpasses and cadences chosen to optimize the discovery of different types of transients. Example analyses are given for SuperMACHO, LSST, and GLAST.
Neolignans from the Leaves of Casearia sylvestris Swartz

Six new neolignans, casearialignans A–F (1–6, resp.) and one known lignan syringaresinol-β-D-glucoside were isolated from the leaves of Casearia sylvestris. Their structures were determined on the basis of 1D- and 2D-NMR, and HR-ESI-MS analyses. The relative and absolute configurations were determined by the value of the coupling constants and CD spectral analysis, respectively.
Braess's Paradox in large random graphs

Braess's Paradox is the counterintuitive fact that removing edges from a network with “selfish routing” can decreasethe latency incurred by traffic in an equilibrium flow. We prove that Braess's Paradox is likely to occur in a natural random network model: with high probability, there is a traffic rate and a set of edges whose removal improves the latency of traffic in an equilibrium flow by a constant factor. © 2010 Wiley Periodicals, Inc. Random Struct. Alg., 2010 A preliminary version of this article appeared in the Proceedings of the 7th ACM Conference on Electronic Commerce, June 2006.
The Penalties of Inefficient Infrastructure

In most developing countries, irrigation, road, and power networks are not in good condition. In Latin America, for example, the effectiveness of such public infrastructure is only about 74% of that of industrialized countries. Low effectiveness imposes a cost on these countries in terms of forgone output. This paper develops a general-equilibrium model to study the long-run consequences of ineffective infrastructure. The model is solved numerically using parameters from seven Latin American countries. Results show that the long run penalty of ineffective infrastructure is about 40% of steady-state real GDP per capita. Raising effectiveness is shown to have sizable positive effects on income per capita, private investment, consumption, and welfare. Nevertheless, policymakers instead usually emphasize building new infrastructure. If effectiveness is low in the existing infrastructure network, new infrastructure investments can negatively affect per-capita income, private investment, consumption, and welfare.
The formation of continental crust: Part 1. A review of some principles; Part 2. An application to the Proterozoic evolution of southern North America

Understanding of the evolution of continental crust has been dominated by work in tectonics, experimental petrology and geochemistry, and geochronology and isotope geochemistry. In part 1, these approaches are discussed in the light of keynote articles, most published by the Geological Society of America, in an attempt to show how new data and new thinking have influenced understanding of the formation and modification of continental crust. In part 2, the evolution of continental crust in southern North America from 1.8 Ga until 1.3 Ga is discussed as an application of ideas generated during the past 30 years.
Analytical and numerical investigation of non–uniform straining and subgrain initiation in bicrystals in channel die compression

Effects of the grain boundary (i.e. interface plane) on deformation and stress state in symmetric FCC bicrystals are investigated. The full range of lattice constraint directions for crystals compressed in a (110) direction within a rigid channel die is considered. The spatial non–uniformity is only two dimensional and in the plane transverse to the loading direction. Principal analytical results are that subgrains begin to form within each crystal and tangential velocity discontinuities extend from interface edges in characteristic directions which depend on crystal orientation. Numerical (finite element) results for several orientations at the end of the elastoplastic transition form purely elastic to fully plastic (multiple–slip) response are compared with the analytical rigid–plastic solutions. Both analytical and numerical results predict subranges of lattice orientations in which there is separation of crystal and channel wall.
Footloose and Pollution-Free

In numerous studies, economists have found little empirical evidence that environmental regulations affect trade flows. In this paper, we propose and test several common explanations for why the effect of environmental regulations on trade may be difficult to detect. We demonstrate that whereas most trade occurs among industrialized economies, environmental regulations have stronger effects on trade between industrialized and developing economies. We find that for most industries, pollution abatement costs are a small component of total costs, and are unrelated to trade flows. In addition, we show that those industries with the largest pollution abatement costs also happen to be the least geographically mobile, or footloose. After accounting for these distinctions, we measure a significant effect of pollution abatement costs on imports from developing countries, and in pollution-intensive, footloose industries.
The Role of Infrastructure in Mexican Economic Reform

This article estimates the relationship between the provision of public infrastructure and private output in sixteen sectors in Mexico. The sector-specific cost functions depend on wages, the cost of capital, and the nominal values of the stocks of three types of infrastructure: electricity, transport, and communications. The article concludes that infrastructure in electricity and communications generally reduces the cost of sectoral production, but transportation infrastructure tends to increase costs of sectoral production. It appears that Mexican public expenditure on electricity and communications has enhanced the productivity of private production, but expenditure on transport may actually have had a detrimental effect on private output. In addition, although in general labor and infrastructure are substitutes, in the case of electricity and communications infrastructure, capital and infrastructure are complements. In the case of transport infrastructure these conclusions are reversed. Copyright 1995 by Oxford University Press.
An ion-source model for first-order beam dynamic codes

A model of a plasma ion source has been developed that approximates the system of Poisson and Boltzman-Vlasov equations normally used to describe ion sources by an external electric field, a collective electric field due to the charge column, and the starting boundary conditions. The equations of this model can be used directly in the Lorentz force equation to calculate trajectories without iteration. >
Twisted Alexander polynomials detect the unknot

Twisted Alexander polynomials of knots in S were introduced by X-S Lin in [7]. They were defined more generally for any finitely presentable group with infinite abelianization by M Wada [11]. Many papers subsequently appeared on the topic. Notable among them is [5], by P Kirk and C Livingston, placing twisted Alexander polynomials of knots in the classical context of abelian invariants. A slightly more general approach by J Cha [1] permits coefficients in a Noetherian unique factorization domain.
Non-degeneracy of some Sobolev Pseudo-norms of fractional Brownian motion

Applying an upper bound estimate for $L^{2}$ small ball probability for fractional Brownian motion (fBm), we prove the non degeneracy of some Sobolev pseudo-norms of fBm.
Convergence to Equilibrium in Local Interaction Games

We study a simple game theoretic model for the spread of an innovation in a network. The diffusion of the innovation is modeled as the dynamics of a coordination game in which the adoption of a common strategy between players has a higher payoff. Classical results in game theory provide a simple condition for an innovation to become widespread in the network. The present paper characterizes the rate of convergence as a function of graph structure. In particular, we derive a dichotomy between well-connected (e.g. random) graphs that show slow convergence and poorly connected, low dimensional graphs that show fast convergence.
Sanitation for Unserved Populations: Technologies, Implementation Challenges, and Opportunities

The global population without complete sanitation services is enormous; it includes those without access to basic, household-level sanitation (2.6 billion) as well as those without adequate collection, treatment, and disposal or reuse of their waste. The main goals of a complete sanitation system are to protect human health and the environment and to recover valuable resources from waste (e.g., water, nutrients, energy). The needs of households and the larger community vary dramatically among the unserved population, as do the financial and institutional resources available to provide sanitation services. Thus, a wide range of technologies is needed that can be adapted to each particular situation. In this chapter, existing sanitation technologies are reviewed, from simple latrines to advanced wastewater treatment, with specific attention to characteristics that affect long-term performance. In addition, the context in which sanitation projects are implemented is discussed, including user preferences and demand, costs and financing, and institutional capacity.
The laser system for the ERL electron source at Cornell University

A master oscillator-power amplifier (MOPA) laser system has been developed to meet the requirements of the Cornell ERL high brightness electron photoinjector. The system is comprised of a Yb-fiber laser oscillator, a single-mode fiber pre-amplifier and a double-clad, large mode area fiber amplifier. The system provides 5 watts average infrared power in a train of 3-ps pulses at 50 MHz. These pulses are efficiently frequency-doubled to produce 2-ps pulses at 520 nm with more than 40 nJ energy per pulse. We demonstrate an efficient longitudinal pulse shaping technique that allows us to achieve 20- to 40-ps-long, nearly flat-top pulses with sharp rise and fall times. We characterize the noise properties of the fiber oscillator and discuss the route to upgrade the system to achieve 130-watt average infrared power and a repetition rate of 1.3 GHz.
Total Synthesis of Theopederin D

The total synthesis of the potent cytotoxin theopederin D has been achieved through the use of an oxidative carbon–carbon bond cleavage reaction to form an acyliminium ion in the presence of acid labile acetal groups Other key transformations include an acid mediated functionalization of a tetrahydrofuranyl alcohol in the presence of a tetrahydropyranyl alcohol, a syn-selective glycal epoxide opening, and a catalytic asymmetric aldehyde-acid chloride condensation.
You Say Illegal, I Say Legitimate: Entrepreneurship in the Informal Economy

The entrepreneurial process drives economic activities in the formal economy; however, little is known theoretically about how the entrepreneurial process works in the informal economy. To address this theoretical gap, we employ a multilevel perspective integrating entrepreneurship theory (microlevel) with institutional (macrolevel) and collective identity (mesolevel) theories to examine the role institutions and collective identity play in the recognition and exploitation of opportunities in the informal economy. Additionally, we explore factors that influence the transition to the formal economy.
Revenue Sharing in Sports Leagues: The Effects on Talent Distribution and Competitive Balance

This article uses a three-stage model of noncooperative and cooperative bargaining in a free agent market to analyze the effect of revenue sharing on the decision of teams to sign a free agent. The...
The effect of collective excitations on the single particle spectra of nuclei

Abstract In deriving the collective excitation spectra of nuclei it is often assumed that the collective modes have negligible effect on the quasi-particle spectrum. An expression is derived for the self-energy of the quasi-particle states including pairing interactions as well as virtual excitation of collective modes, from which the validity of the above assumption can be investigated.
A new scintillator tile/fiber preshower detector for the CDF central calorimeter

A detector designed to measure early particle showers has been installed in front of the central Collider Detector at Fermilab (CDF) calorimeter at the Tevatron. This new preshower detector is based on scintillator tiles coupled to wavelength-shifting fibers read out by multianode photomultipliers and has a total of 3072 read-out channels. The replacement of the old gas detector was required due to an expected increase in instantaneous luminosity of the Tevatron collider in the next few years. Calorimeter coverage, jet energy resolution, and electron and photon identification are among the expected improvements. The final detector design, together with the R&D studies that led to the choice of scintillator and fiber, mechanical assembly, and quality control are presented. The detector was installed in the fall 2004 Tevatron shutdown and started collecting colliding beam data by the end of the same year. First measurements indicate a light yield of 12 photoelectrons/MIP, a more than two-fold increase over the design goals.
Fast multiscale statistical signal processing algorithms

It is shown that a large set of (not necessarily stationary) correlation matrices may be transformed into a matrix that consists of essentially banded subblocks. The transformation is accomplished by premultiplication and postmultiplication with an orthogonal matrix whose elements are derived from the impulse response of a suitably designed cascade of alias-free multirate analysis filter banks. It is further proved that the Cholesky factor of the transformed matrix also consists of essentially banded subblocks. These two observations are combined to show that the linear positive definite systems of equations that arise in statistical signal processing can be solved in O(max(N log/sup 2/ (N), N/sup 2/)) operations while matrix-vector multiplication steps may be implemented in O(N log (N)) operations. An error analysis of the proposed linear positive definite system solver is also provided. >
Honeycomb pattern formation by laser-beam filamentation in atomic sodium vapor

This study presents examples of observed optical pattern formation in which a single laser beam propagating through atomic sodium vapor without feedback develops a stable, regular transverse structure. In particular, a three-filament near-field pattern leading to a honeycomb far-field pattern occurs at intensities near the saturation intensity and at powers larger than (but of the order of magnitude of) the critical power for self-focusing. The three-filament pattern has a uniform phase profile and strongly correlated power fluctuations, which suggest that it is perhaps a quantum image. These observations are also found to be in good agreement with numerical simulations of filamentation in a two-level atomic medium.
Efficient tests of long-run causation in trivariate VAR processes with a rolling window study of the money–income relationship

This paper develops a simple sequential multiple horizon non- causation test strategy for trivariate VAR models (with one auxiliary variable). We apply the test strategy to a rolling window study of money supply and real income, with the price of oil, the unemployment rate and the spread between the Treasury bill and commercial paper rates as auxiliary processes. Ours is the first study to control simultaneously for common stochastic trends, sensi- tivity of causality tests to chosen sample period, null hypothesis over-rejection, sequential test size bounds, and the possibility of causal delays. Evidence sug- gests highly significant direct or indirect causality from M1 to real income, in particular through the unemployment rate and M2 once we control for cointe- gration.
The Role of Mass and Environment in Multiple-Star Formation: A 2MASS Survey of Wide Multiplicity in Three Young Associations

We present the results of a search for wide binary systems among 783 members of three nearby young associations: Taurus-Auriga, Chamaeleon I, and two subgroups of Upper Scorpius. Near-infrared (JHK) imagery from 2MASS was analyzed to search for wide (1"-30"; ~150-4500 AU) companions to known association members, using color-magnitude cuts to reject likely background stars. We identify a total of 131 candidate binary companions with colors consistent with physical association, of which 39 have not been identified previously in the literature. Our results suggest that the wide binary frequency is a function of both mass and environment, with significantly higher frequencies among high-mass stars than lower mass stars and in the T associations than in the OB association. We discuss the implications for wide binary formation and conclude that the environmental dependence is not a direct result of stellar density or total association mass, but instead might depend on another environmental parameter like the gas temperature. The binary populations in these associations generally follow the empirical mass-maximum separation relation observed for field binaries, but we have found one candidate low-mass system (USco 160611.9-193532; M_(tot) ~ 0.4 M_⊙) that has a projected separation (10.8"; 1550 AU) much larger than the suggested limit for its mass. Finally, we find that the binary frequency in the USco-B subgroup is significantly higher than in the USco-A subgroup and is consistent with the measured values in Taurus and ChamI. This discrepancy, the absence of high-mass stars in USco-B, and its marginally distinct kinematics suggest that it might not be directly associated with the OB associations of Sco-Cen but instead represents an older analog of the younger ρ Oph or Lupus associations.
Age of blood as a limitation for transfusion: potential impact on blood inventory and availability

BACKGROUND: Evolving concerns about storage lesions for red blood cells (RBCs) have led to ongoing trials evaluating the benefits of transfusing fresher blood to acutely ill patients. STUDY DESIGN AND METHODS: We evaluated several RBC maximum shelf lives (MSLs) and their impact on RBC availability and outdate rate. First, we determined the mean age of the RBC units in our inventory by analyzing the data set of 18,987 nonirradiated RBC units transfused at our institution from April 2008 to March 2009. Second, we determined the feasibility of issuing RBC units of a designated age to patients using the same data set. We defined six scenarios where RBC units have different MSLs: Scenarios 1, 2, 3, 4, and 5 used a MSL of 7, 14, 21, 28, and 35 days, respectively. Scenario 6 used a combination of different MSLs depending on the category of patients. RESULTS: RBC units spent on average 8.6 days on the shelf with a mean age of 10.2 days at delivery and 18.8 days at issue for transfusion. Using the original 18,987 data points, we observed a shortfall in the availability of RBC units, decreased by 51, 20, 10, 4, 1, and 0% and an increase in the outdate rate to 3.2, 2.2, 1.0, 0.6, 0.4, and 4.5% for Scenarios 1, 2, 3, 4, 5, and 6, respectively, compared to baseline. CONCLUSION: Changing the MSL for RBC units would require novel approaches to RBC inventory management to meet hospital demands with acceptable outdate rates.
Approximate decentralized Bayesian inference

This paper presents an approximate method for performing Bayesian inference in models with conditional independence over a decentralized network of learning agents. The method first employs variational inference on each individual learning agent to generate a local approximate posterior, the agents transmit their local posteriors to other agents in the network, and finally each agent combines its set of received local posteriors. The key insight in this work is that, for many Bayesian models, approximate inference schemes destroy symmetry and dependencies in the model that are crucial to the correct application of Bayes' rule when combining the local posteriors. The proposed method addresses this issue by including an additional optimization step in the combination procedure that accounts for these broken dependencies. Experiments on synthetic and real data demonstrate that the decentralized method provides advantages in computational performance and predictive test likelihood over previous batch and distributed methods.
Web Footprints of Firms: Using Online Isomorphism for Competitor Identification

Competitive isomorphism refers to the phenomenon of competing firms becoming similar as they mimic each other under common market forces. With the growing presence of firms as well as their consumers and suppliers on the Web, we discover a parallel phenomenon of online isomorphism wherein the Web footprints of competing firms are found to overlap. We propose new online metrics based on the content, in-links, and out-links of firms' websites to measure the presence of online isomorphism as well as uncover its utility in predicting competitor relationships. Through rigorous analysis involving more than 2,600 firms, we find that predictive models for competitor identification based on online metrics are largely superior to those using offline data such as Standard Industrial Classification codes and market values of firms. In addition, combining online and offline metrics can boost the predictive performance. We also find that such models are valuable for identifying nuances of competitor relationships such as asymmetry and the role of industrial divisions. Furthermore, the suggested predictive models can effectively rank firms in an industrial division by their likelihood of being competitors to a focal firm as well as identify new future competitors, thus adding to a portfolio of evidence indicating their utility for managers and analysts.
Borderline Personality Disorder and Suicidality

A 35-year-old woman, an academic professional, sought outpatient treatment for chronic dysphoria, a pattern of turbulent and unsuccessful interpersonal relationships, and a state of barely concealed rage that she attributed to the shortcomings and failures of others. She received a diagnosis of borderline personality disorder and began twice weekly psychotherapy. About 1 year into treatment, a stormy but long-term relationship with a man broke up, and the patient became angry and agitated. Although she blamed the man for the failed relationship and chronicled his many shortcomings, her mood shifted over several weeks and she reported feeling depressed and suicidal, hopeless about her future, and uninterested in work, friends, or family. How common and how serious is suicidal ideation and/or behavior in patients with borderline personality disorder? How should it be evaluated and managed? What is the appropriate role of hospitalization in such cases?
Global rigidity of solvable group actions on S^1

In this paper we nd all solvable subgroups of Di ! (S 1 ) and classify their actions. We also investigate the C r local rigidity of actions of the solvable Baumslag{Solitar groups on the circle.
Controlled reduction of nitroalkanes to alkyl hydroxylamines or amines by samarium diiodide

Abstract Alkyl hydroxylamines and alkyl amines have been prepared from nitroalkanes and SmI 2 under mild conditions in moderate to good yields.
Sato-Tate theorem for families and low-lying zeros of automorphic L-functions

We consider certain families of automorphic representations over number fields arising from the principle of functoriality of Langlands. Let $$G$$ be a reductive group over a number field $$F$$ which admits discrete series representations at infinity. Let $$^{L}G=\widehat{G} \rtimes \mathrm{Gal}(\bar{F}/F)$$ be the associated $$L$$ -group and $$r:{}^L G\rightarrow \mathrm{GL}(d,\mathbb {C})$$ a continuous homomorphism which is irreducible and does not factor through $$\mathrm{Gal}(\bar{F}/F)$$ . The families under consideration consist of discrete automorphic representations of $$G(\mathbb {A}_F)$$ of given weight and level and we let either the weight or the level grow to infinity. We establish a quantitative Plancherel and a quantitative Sato–Tate equidistribution theorem for the Satake parameters of these families. This generalizes earlier results in the subject, notably of Sarnak (Prog Math 70:321–331, 1987) and Serre (J Am Math Soc 10(1):75–102, 1997). As an application we study the distribution of the low-lying zeros of the associated family of $$L$$ -functions $$L(s,\pi ,r)$$ , assuming from the principle of functoriality that these $$L$$ -functions are automorphic. We find that the distribution of the $$1$$ -level densities coincides with the distribution of the $$1$$ -level densities of eigenvalues of one of the unitary, symplectic and orthogonal ensembles, in accordance with the Katz–Sarnak heuristics. We provide a criterion based on the Frobenius–Schur indicator to determine this symmetry type. If $$r$$ is not isomorphic to its dual $$r^\vee $$ then the symmetry type is unitary. Otherwise there is a bilinear form on $$\mathbb {C}^d$$ which realizes the isomorphism between $$r$$ and $$r^\vee $$ . If the bilinear form is symmetric (resp. alternating) then $$r$$ is real (resp. quaternionic) and the symmetry type is symplectic (resp. orthogonal).
Globalization, Marketing Resources, and Performance: Evidence From China:

Two important areas are underexplored in the relationship between marketing resources and performance. First, the subject has been primarily investigated in the context of Western countries, and inadequate attention has been given to emerging economies. Second, despite the recent growth in globalization, the moderating role of globalization on the link between marketing resources and performance has not been investigated. Addressing these important gaps, this article focuses on an emerging economy (China) and explores the moderating effect of globalization on this link. Specifically, the authors develop several hypotheses highlighting the moderating role of globalization activities (global product sourcing, global market seeking, and global partnership) on the link between marketing resources (market orientation, entrepreneurial orientation, and innovative capability) and firm performance. The findings of the moderating role of globalization provide several important implications for marketing theory development and managerial practice.
Digital codec for real-time processing of broadcast quality video signals at 1.8 bits/pixel

The authors present the hardware implementation of a digital television bandwidth compression algorithm which processes standard NTSC (National Television Systems Committee) composite color television signals and produces broadcast-quality video in real time at an average of 1.8 b/pixel. The sampling rate used with this algorithm results in 768 samples over the active portion of each video line by 512 active video lines per video frame. The algorithm is based on differential pulse code modulation (DPCM), but additionally utilizes a nonadaptive predictor, nonuniform quantizer, and multilevel Huffman coder to reduce the data rate substantially below that achievable with straight DPCM. The nonadaptive predictor and multilevel Huffman coder combine to set this technique apart from prior-art DPCM encoding algorithms. The authors describe the data compression algorithm and the hardware implementation of the codec and provide performance results. >
Uncertainty and the Geography of the Great Recession

We document the link between increased levels of economic and policy uncertainty and unemployment at the state-level during the 2007-2009 recession. The cross-sectional variation in uncertainty robustly matches the distribution of employment outcomes during this period. When we instrument for this cross-sectional variation using preexisting institutions, we find evidence for a causal role for uncertainty in increasing unemployment. A simple model of hiring and firing under uncertainty rationalizes these results, and the within-state distribution of effects across industries, occupations, and individuals is consistent with this model’s predictions. Together, these results suggest that increased uncertainty contributed to the severity of the Great Recession.
Convergence Rates of Random Walk on Irreducible Representations of Finite Groups

Random walk on the set of irreducible representations of a finite group is investigated. For the symmetric and general linear groups, a sharp convergence rate bound is obtained and a cutoff phenomenon is proved. As related results, an asymptotic description of Plancherel measure of the finite general linear groups is given, and a connection of these random walks with the hidden subgroup problem of quantum computing is noted.
The Good, the Bad, and the Ambivalent: Managing Identification among Amway Distributors

An ethnographic study of distributors for Amway, a network marketing organization, examines the practices and processes involved in managing members' organizational identification. It shows that this organization manages identification by using two types of practices: sensebreaking practices that break down meaning and sensegiving practices that provide meaning. When both sensebreaking and sensegiving practices are successful, members positively identify with the organization. When either sensebreaking or sensegiving practices fail, members deidentify, disidentify, or experience ambivalent identification with the organization. A general model of identification management is posited, and implications for both theory and practice are offered.
Milestones in Marketing

We invited John Quelch and Katherine Jocz, authors of Greater Good: How Good Marketing Makes for Better Democracy (2008), to discuss some of the articles they found most interesting and important from the past half-century of marketing journals.