cssi/SciSciGPT-SciSciNet huggingface dataset:
Stabilizers of actions of lattices in products of groups

We prove that any ergodic non-atomic probability-preserving action of an irreducible lattice in a semisimple group, with at least one factor being connected and of higher-rank, is essentially free. This generalizes the result of Stuck and Zimmer [Stabilizers for ergodic actions of higher rank semisimple groups. Ann. of Math. (2) 139(3) (1994), 723–747], who found that the same statement holds when the ambient group is a semisimple real Lie group and every simple factor is of higher-rank. We also prove a generalization of a result of Bader and Shalom [Factor and normal subgroup theorems for lattices in products of groups. Invent. Math. 163(2) (2006), 415–454] by showing that any probability-preserving action of a product of simple groups, with at least one having property , which is ergodic for each simple subgroup, is either essentially free or essentially transitive. Our method involves the study of relatively contractive maps and the Howe–Moore property, rather than relying on algebraic properties of semisimple groups and Poisson boundaries, and introduces a generalization of the ergodic decomposition to invariant random subgroups, which is of independent interest.
A cosmological basis for E = mc2

The Universe has a gravitational horizon with a radius Rh = c/H coincident with that of the Hubble sphere. This surface separates null geodesics approaching us from those receding, and as free-fall...
The Fading of Supernova Remnant Cassiopeia A from 38 MHz to 16.5 GHz from 1949 to 1999 with New Observations at 1405 MHz

We report 1405 MHz measurements of the flux density of the ≈320-year-old supernova remnant Cassiopeia A, relative to the flux density of Cygnus A, made between 1995 and 1999. When compared to measurements made between 1957 and 1976, we find that the rate at which Cassiopeia A has been fading at this and nearby frequencies has changed from ≈0.9% yr-1 in the 1960s to ≈0.6%-0.7% yr-1 now. Furthermore, we have collected from the literature measurements of this fading rate at lower (38-300 MHz) and higher (7.8-16.5 GHz) frequencies. We show that the fading rate has dropped by a factor of ≈3 over the past 50 years at the lower frequencies, while remaining relatively constant at the higher frequencies, which is in agreement with the findings of others. Our findings at 1405 MHz, in conjunction with a measurement of the fading rate at the nearby frequency of 927 MHz by Vinyajkin, show an intermediate behavior at intermediate frequencies. We also find that Cassiopeia A, as of ≈1990, was fading at about the same rate, ≈0.6%-0.7% yr-1, at all of these frequencies. Future measurements are required to determine whether the fading rate will continue to decrease at the lower frequencies, or whether Cassiopeia A will now fade at a relatively constant rate at all of these frequencies.
On network simplification for Gaussian Half-Duplex diamond networks

This paper investigates the simplification problem in Gaussian Half-Duplex (HD) diamond networks. The goal is to answer the following question: what is the minimum (worst-case) fraction of the total HD capacity that one can always achieve by smartly selecting a subset of k relays, out of the N possible ones? We make progress on this problem for k = 1 and k = 2 and show that for N = k + 1, k ∈ |1, 2} at least k/k+1 of the total HD capacity is always approximately (i.e., up to a constant gap) achieved. Interestingly, and differently from the Full-Duplex (FD) case, the ratio in HD depends on N, and decreases as N increases. For all values of N and k for which we derive worst case fractions, we also show these to be approximately tight. This is accomplished by presenting N-relay Gaussian HD diamond networks for which the best k-relay subnetwork has an approximate HD capacity equal to the worst-case fraction of the total approximate HD capacity. Moreover, we provide additional comparisons between the performance of this simplification problem for HD and FD networks, which highlight their different natures.
Gamma-ray Loudness, Synchrotron Peak Frequency, and Parsec-Scale Properties of Blazars Detected by the Fermi Large Area Telescope

The parsec-scale radio properties of 232 active galactic nuclei, most of which are blazars, detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope have been observed contemporaneously by the Very Long Baseline Array (VLBA) at 5 GHz. Data from both the first 11 months (1FGL) and the first 2 years (2FGL) of the Fermi mission were used to investigate these sources' {gamma}-ray properties. We use the ratio of the {gamma}-ray-to-radio luminosity as a measure of {gamma}-ray loudness. We investigate the relationship of several radio properties to {gamma}-ray loudness and to the synchrotron peak frequency. There is a tentative correlation between {gamma}-ray loudness and synchrotron peak frequency for BL Lac objects in both 1FGL and 2FGL, and for flat-spectrum radio quasars (FSRQs) in 2FGL. We find that the apparent opening angle tentatively correlates with {gamma}-ray loudness for FSRQs, but only when we use the 2FGL data. We also find that the total VLBA flux density correlates with the synchrotron peak frequency for BL Lac objects and FSRQs. The core brightness temperature also correlates with synchrotron peak frequency, but only for the BL Lac objects. The low-synchrotron-peaked (LSP) BL Lac object sample shows indications of contamination bymore » FSRQs which happen to have undetectable emission lines. There is evidence that the LSP BL Lac objects are more strongly beamed than the rest of the BL Lac object population.« less
Handling Model and Implementation Uncertainties via an Adaptive Discrete Sliding Mode Controller Design

Analog-to-digital conversion (ADC) and uncertainties in modeling the plant dynamics are the main sources of imprecisions in the design cycle of model-based controllers. These implementation and model uncertainties should be addressed in the early stages of the controller design, otherwise they could lead to failure in the controller performance and consequently increase the time and cost required for completing the controller verification and validation (V&V) with more iterative loops. In this paper, a new control approach is developed based on a nonlinear discrete sliding mode controller (DSMC) formulation to mitigate the ADC imprecisions and model uncertainties. To this end, a DSMC design is developed against implementation imprecisions by incorporating the knowledge of ADC uncertainties on control inputs via an online uncertainty prediction and propagation mechanism. Next, a generic online adaptive law will be derived to compensate for the impact of an unknown parameter in the controller equations that is assumed to represent the model uncertainty. The final proposed controller is an integrated adaptive DSMC with robustness to implementation and model uncertainties that includes (i) an online ADC uncertainty mechanism, and (ii) an online adaptation law. The proposed adaptive control approach is evaluated on a nonlinear automotive engine control problem in real-time using a processor-in-the-loop (PIL) setup with an actual electronic control unit (ECU). The results reveal that the proposed adaptive control technique removes the uncertainty in the model fast, and significantly improves the robustness of the controllers to ADC imprecisions. This provides up to 60% improvement in the performance of the controller under implementation and model uncertainties compared to a baseline DSMC, in which there are no incorporated ADC imprecisions.
Generation of 87 Rb resonant bright two-mode squeezed light with four-wave mixing

Squeezed states of light have found their way into a number of applications in quantum-enhanced metrology due to their reduced noise properties. In order to extend such an enhancement to metrology experiments based on atomic ensembles, an efficient light-atom interaction is required. Thus, there is a particular interest in generating narrow-band squeezed light that is on atomic resonance. This will make it possible not only to enhance the sensitivity of atomic based sensors, but also to deterministically transfer quantum correlations between two distant atomic ensembles. We generate bright two-mode squeezed states of light, or twin beams, with a non-degenerate four-wave mixing (FWM) process in hot 85Rb in a double-lambda configuration. Given the proximity of the energy levels in the D1 line of 85Rb and 87Rb, we are able to operate the FWM in 85Rb in a regime that generates two-mode squeezed states in which both modes are simultaneously on resonance with transitions in the D1 line of 87Rb, one mode with the F = 2 to F' = 2 transition and the other one with the F = 1 to F' = 1 transition. For this configuration, we obtain an intensity difference squeezing level of 3.5 dB. Moreover, the intensity difference squeezing increases to -5.4 dB and -5.0 dB when only one of the modes of the squeezed state is resonant with the D1 F = 2 to F' =-2 or F = 1 to F' = 1 transition of 87Rb, respectively.
TRANSIT AND RADIAL VELOCITY SURVEY EFFICIENCY COMPARISON FOR A HABITABLE ZONE EARTH

Transit and radial velocity searches are two techniques for identifying nearby extrasolar planets to Earth that transit bright stars. Identifying a robust sample of these exoplanets around bright stars for detailed atmospheric characterization is a major observational undertaking. In this study we describe a framework that answers the question of whether a transit or radial velocity survey is more efficient at finding transiting exoplanets given the same amount of observing time. Within the framework we show that a transit survey's window function can be approximated using the hypergeometric probability distribution. We estimate the observing time required for a transit survey to find a transiting Earth-sized exoplanet in the habitable zone (HZ) with an emphasis on late-type stars. We also estimate the radial velocity precision necessary to detect the equivalent HZ Earth-mass exoplanet that also transits when using an equal amount of observing time as the transit survey. We find that a radial velocity survey with σ{sub rv} ∼ 0.6 m s{sup –1} precision has comparable efficiency in terms of observing time to a transit survey with the requisite photometric precision σ{sub phot} ∼ 300 ppm to find a transiting Earth-sized exoplanet in the HZ of late M dwarfs. For super-Earths,more » a σ{sub rv} ∼ 2.0 m s{sup –1} precision radial velocity survey has comparable efficiency to a transit survey with σ{sub phot} ∼ 2300 ppm.« less
Scalable Communication Endpoints for MPI+Threads Applications

Hybrid MPI+threads programming is gaining prominence as an alternative to the traditional “MPI everywhere” model to better handle the disproportionate increase in the number of cores compared with other on-node resources. Current implementations of these two models represent the two extreme cases of communication resource sharing in modern MPI implementations. In the MPI-everywhere model, each MPI process has a dedicated set of communication resources (also known as endpoints), which is ideal for performance but is resource wasteful. With MPI+threads, current MPI implementations share a single communication endpoint for all threads, which is ideal for resource usage but is hurtful for performance. In this paper, we explore the tradeoff space between performance and communication resource usage in MPI+threads environments. We first demonstrate the two extreme cases-one where all threads share a single communication endpoint and another where each thread gets its own dedicated communication endpoint (similar to the MPI-everywhere model) and showcase the inefficiencies in both these cases. Next, we perform a thorough analysis of the different levels of resource sharing in the context of Mellanox InfiniBand. Using the lessons learned from this analysis, we design an improved resource-sharing model to produce scalable communication endpoints that can achieve the same performance as with dedicated communication resources per thread but using just a third of the resources.
ON THE KNOT FLOER FILTRATION OF THE CONCORDANCE GROUP

The knot Floer complex together with the associated concordance invariant e can be used to define a filtration on the smooth concordance group. We show that the indexing set of this filtration contains ℕ × ℤ as an ordered subset.
Naturally dualizable algebras omitting types 1 and 5 have a cube term

An early result in the theory of Natural Dualities is that an algebra with a near unanimity (NU) term is dualizable. A converse to this is also true: if \({\mathcal{V}(\mathbb{A})}\) is congruence distributive and \({\mathbb{A}}\) is dualizable, then \({\mathbb{A}}\) has an NU term. An important generalization of the NU term for congruence distributive varieties is the cube term for congruence modular (CM) varieties, and it has been thought that a similar characterization of dualizability for algebras in a CM variety would also hold. We prove that if \({\mathbb{A}}\) omits tame congruence types 1 and 5 (all locally finite CM varieties omit these types) and is dualizable, then \({\mathbb{A}}\) has a cube term.
The AGN Hubble Diagram and its implications for cosmology

We use a recently proposed luminosity distance measure for relatively nearby active galactic nuclei (AGNs) to test the predicted expansion of the Universe in the $R_{\mathrm{h}}=ct$ and $\varLambda\mathrm{CDM}$ cosmologies. This comparative study is particularly relevant to the question of whether or not the Universe underwent a transition from decelerated to accelerated expansion, which is believed to have occurred—on the basis of Type Ia SN studies—within the redshift range ( $0\lesssim z\lesssim 1.3$ ) that will eventually be sampled by these objects. We find that the AGN Hubble Diagram constructed from currently available sources does not support the existence of such a transition. While the scatter in the AGN data is still too large for any firm conclusions to be drawn, the results reported here nonetheless somewhat strengthen similar results of comparative analyses using other types of source. We show that the Akaike, Kullback, and Bayes Information Criteria all consistently yield a likelihood of $\sim 84\mbox{--}96~\%$ that $R_{\mathrm{h}}=ct$ is closer to the “true” cosmology than $\varLambda\mathrm{CDM}$ is, though neither model adequately accounts for the data, suggesting an unnaccounted-for source of scatter.
The tipping point: A mathematical model for the profit-driven abandonment of restaurant tipping

The custom of voluntarily tipping for services rendered has gone in and out of fashion in America since its introduction in the 19th century. Restaurant owners that ban tipping in their establishments often claim that social justice drives their decisions, but we show that rational profit-maximization may also justify the decisions. Here, we propose a conceptual model of restaurant competition for staff and customers, and we show that there exists a critical conventional tip rate at which restaurant owners should eliminate tipping to maximize profits. Because the conventional tip rate has been increasing steadily for the last several decades, our model suggests that restaurant owners may abandon tipping en masse when that critical tip rate is reached.
The effective chiral Lagrangian from the theta term

Abstract We construct the effective chiral Lagrangian involving hadronic and electromagnetic interactions originating from the QCD θ ¯ term. We impose vacuum alignment at both quark and hadronic levels, including field redefinitions to eliminate pion tadpoles. We show that leading time-reversal-violating (TV) hadronic interactions are related to isospin-violating interactions that can in principle be determined from charge-symmetry-breaking experiments. We discuss the complications that arise from TV electromagnetic interactions. Some implications of the expected sizes of various pion–nucleon TV interactions are presented, and the pion–nucleon form factor is used as an example.
Bayes, Jeffreys, Prior Distributions and the Philosophy of Statistics

I actually own a copy of Harold Jeffreys's Theory of Probability but have only read small bits of it, most recently over a decade ago to confirm that, indeed, Jef freys was not too proud to use a classical chi-squared p-value when he wanted to check the misfit of a model to data (Gelman, Meng and Stern, 2006). I do, how ever, feel that it is important to understand where our probability models come from, and I welcome the op portunity to use the present article by Robert, Chopin and Rousseau as a platform for further discussion of foundational issues.2 In this brief discussion I will argue the following: (1) in thinking about prior distributions, we should go beyond Jeffreys's principles and move toward weakly informative priors; (2) it is natural for those of us who work in social and computational sciences to favor complex models, contra Jeffreys's preference for sim plicity; and (3) a key generalization of Jeffreys's ideas is to explicitly include model checking in the process of data analysis.
Low-derivative operators of the Standard Model effective field theory via Hilbert series methods

In this work, we explore an extension of Hilbert series techniques to count operators that include derivatives. For sufficiently low-derivative operators, we conjecture an algorithm that gives the number of invariant operators, properly accounting for redundancies due to the equations of motion and integration by parts. Specifically, the conjectured technique can be applied whenever there is only one Lorentz invariant for a given partitioning of derivatives among the fields. At higher numbers of derivatives, equation of motion redundancies can be removed, but the increased number of Lorentz contractions spoils the subtraction of integration by parts redundancies. While restricted, this technique is sufficient to automatically recreate the complete set of invariant operators of the Standard Model effective field theory for dimensions 6 and 7 (for arbitrary numbers of flavors). At dimension 8, the algorithm does not automatically generate the complete operator set; however, it suffices for all but five classes of operators. For these remaining classes, there is a well defined procedure to manually determine the number of invariants. Assuming our method is correct, we derive a set of 535 dimension-8 N f = 1 operators.
Hard X-Ray Excess from the Magnificent Seven Neutron Stars

We report significant hard X-ray excesses in the energy range 2-8 keV for two nearby isolated neutron stars RX J1856.6-3754 and RX J0420.0-5022. These neutron stars have previously been observed in soft X-rays to have nearly thermal spectra at temperatures ~100 eV, which are thought to arise from the warm neutron star surfaces. We find nontrivial hard X-ray spectra well above the thermal surface predictions with archival data from the XMM-Newton and Chandra X-ray telescopes. We analyze possible systematic effects that could generate such spurious signals, such as nearby X-ray point sources and pileup of soft X-rays, but we find that the hard X-ray excesses are robust to these systematics. We also investigate possible sources of hard X-ray emission from the neutron stars and find no satisfactory explanation with known mechanisms, suggesting that a novel source of X-ray emission is at play. We do not find high-significance hard X-ray excesses from the other five Magnificent Seven isolated neutron stars.
Inverse scattering transform for the focusing nonlinear Schrödinger equation with counterpropagating flows

The inverse scattering transform for the focusing nonlinear Schrodinger equation is presented for a general class of initial conditions whose asymptotic behavior at infinity consists of counterpropagating waves. The formulation takes into account the branched nature of the two asymptotic eigenvalues of the associated scattering problem. The Jost eigenfunctions and scattering coefficients are defined explicitly as single-valued functions on the complex plane with jump discontinuities along certain branch cuts. The analyticity properties, symmetries, discrete spectrum, asymptotics and behavior at the branch points are discussed explicitly. The inverse problem is formulated as a matrix Riemann-Hilbert problem with poles. Reductions to all cases previously discussed in the literature are explicitly discussed. The scattering data associated to a few special cases consisting of physically relevant Riemann problems are explicitly computed.
Dimension of the Exceptional Set in the Aronszajn–Donoghue Theorem for Finite Rank Perturbations

The classical Aronszajn-Donoghue theorem states that for a rank one perturbation of a self-adjoint operator (by a cyclic vector) the singular parts of the spectral measures of the original and perturbed operators are mutually singular. As simple direct sum type examples show, this result does not hold for finite rank perturbations. However, the set of exceptional perturbations is pretty small. Namely, for a family of rank $d$ perturbations $A_{\boldsymbol{\alpha}} := A +\mathbf{B} \boldsymbol{\alpha} \mathbf{B}^*$, $\mathbf{B}:\mathbb{C}^d\to \mathbf{H}$, with Ran$\,\mathbf{B}$ being cyclic for $A$, parametrized by $d\times d$ Hermitian matrices $\boldsymbol{\alpha}$, the singular parts of the spectral measures of $A$ and $A_{\boldsymbol{\alpha}}$ are mutually singular for all $\boldsymbol{\alpha}$ except for a small exceptional set $E$. It was shown earlier by the first two authors that $E$ is a subset of measure zero of the space $\mathbf{H}(d)$ of $d\times d$ Hermitian matrices. In this paper we show that the set $E$ has small Hausdorff dimension, $\dim E \le \dim\mathbf{H}(d)-1 = d^2-1$.
The integration and testing program for the Simons Observatory Large Aperture Telescope optics tubes

The Simons Observatory (SO) will be a CMB survey experiment with three small-aperture telescopes and one large-aperture telescope (the LAT), which will observe from the Atacama Desert in Chile. In total, SO will field over 60,000 TES bolometers in six spectral bands centered between 27 and 280 GHz. The 6 m LAT, targeting the smaller angular scales of the CMB, utilizes a cryogenic receiver (LATR) designed to house up to 13 individual optics tubes. The scientific objectives of the SO project requires these optics tubes to achieve high-throughput optical performance while maintaining exquisite control of systematic effects. We describe the integration and testing program for the LATR optics tubes being carried out to verify the design and assembly of the tubes before deployment. The program includes a quick turn-around single tube test cryostat. We discuss the optical design specifications the tubes for deployment and the suite of optical test equipment prepared for these measurements.
Insights into functional mitral regurgitation using transillumination rendering

Secondary mitral regurgitation has been originally explained by tethering of the structurally normal mitral leaflets or by mitral annular dilation after atrial remodeling. Advances in echocardiography have provided more insights into functional anatomy of the mitral valve leaflets as active participants in this entity.
Classification of atomic environments via the Gromov–Wasserstein distance

Abstract Interpreting molecular dynamics simulations usually involves automated classification of local atomic environments to identify regions of interest. Existing approaches are generally limited to a small number of reference structures and only include limited information about the local chemical composition. This work proposes to use a variant of the Gromov–Wasserstein (GW) distance to quantify the difference between a local atomic environment and a set of arbitrary reference environments in a way that is sensitive to atomic displacements, missing atoms, and differences in chemical composition. This involves describing a local atomic environment as a finite metric measure space, which has the additional advantages of not requiring the local environment to be centered on an atom and of not making any assumptions about the material class. Numerical examples illustrate the efficacy and versatility of the algorithm.
Massive celestial fermions

In an effort to further the study of amplitudes in the celestial CFT (CCFT), we construct conformal primary wavefunctions for massive fermions. Upon explicitly calculating the wavefunctions for Dirac fermions, we deduce the corresponding transformation of momentum space amplitudes to celestial amplitudes. The shadow wavefunctions are shown to have opposite spin and conformal dimension 2 − ∆. The Dirac conformal primary wave- functions are delta function normalizable with respect to the Dirac inner product provided they lie on the principal series with conformal dimension ∆ = 1 + iλ for λ ∈ ℝ. It is shown that there are two choices of a complete basis: single spin $$ J=\frac{1}{2} $$ or $$ J=-\frac{1}{2} $$ and λ ∈ ℝ or multiple spin $$ J=\pm \frac{1}{2} $$ and λ ∈ ℝ+∪0. The massless limit of the Dirac conformal primary wavefunctions is shown to agree with previous literature. The momentum generators on the celestial sphere are derived and, along with the Lorentz generators, form a representation of the Poincare algebra. Finally, we show that the massive spin-1 conformal primary wavefunctions can be constructed from the Dirac conformal primary wavefunctions using the standard Clebsch-Gordan coefficients. We use this procedure to write the massive spin- $$ \frac{3}{2} $$ , Rarita-Schwinger, conformal primary wavefunctions. This provides a prescription for constructing all massive fermionic and bosonic conformal primary wavefunctions starting from spin- $$ \frac{1}{2} $$ .
GraphChallenge.org Triangle Counting Performance

The rise of graph analytic systems has created a need for new ways to measure and compare the capabilities of graph processing systems. The MIT/Amazon/IEEE Graph Challenge has been developed to provide a well-defined community venue for stimulating research and highlighting innovations in graph analysis software, hardware, algorithms, and systems. GraphChallenge.org provides a wide range of pre-parsed graph data sets, graph generators, mathematically defined graph algorithms, example serial implementations in a variety of languages, and specific metrics for measuring performance. The triangle counting component of GraphChallenge.org tests the performance of graph processing systems to count all the triangles in a graph and exercises key graph operations found in many graph algorithms. In 2017, 2018, and 2019 many triangle counting submissions were received from a wide range of authors and organizations. This paper presents a performance analysis of the best performers of these submissions. These submissions show that their state-of-the-art triangle counting execution time, $T_{tri}$ , is a strong function of the number of edges in the graph, $N_{e}$ , which improved significantly from 2017 ( $T_{tri} \approx (N_{e}/10^{8})4/3)$ to 2018 ( $T_{tri}\approx N_{e}/10^{9})$ and remained comparable from 2018 to 2019. Graph Challenge provides a clear picture of current graph analysis systems and underscores the need for new innovations to achieve high performance on very large graphs.
Monotonicity properties of the gamma family of distributions

Abstract For real a > 0 , let X a denote a random variable with the gamma distribution with parameters a and 1. Then P ( X a − a > c ) is increasing in a for each real c ⩾ 0 ; non-increasing in a for each real c ⩽ − 1 ∕ 3 ; and non-monotonic in a for each c ∈ ( − 1 ∕ 3 , 0 ) . This extends and/or refines certain previously established results.
Are Moral Intuitions Heritable

Two prominent theoretical frameworks in moral psychology, Moral Foundations and Dual Process Theory, share a broad foundational assumption that individual differences in human morality are dispositional and in part due to genetic variation. The only published direct test of heritability, however, found little evidence of genetic influences on moral judgments using instrumentation approaches associated with Moral Foundations Theory. This raised questions about one of the core assumptions underpinning intuitionist theories of moral psychology. Here we examine the heritability of moral psychology using the moral dilemmas approach commonly used in Dual Process Theory research. Using such measures, we find consistent and significant evidence of heritability. These findings have important implications not only for understanding which measures do, or do not, tap into the genetically influenced aspects of moral decision-making, but in better establishing the utility and validity of different intuitionist theoretical frameworks and the source of why people differ in those frameworks.
Producing 3D friction loads by tracking the motion of the contact point on bodies in mutual contact

We outline a phenomenological model to assess friction at the interface between two bodies in mutual contact. Although the approach is general, the application inspiring the approach is the discrete element method. The kinematics of the friction process is expressed in terms of the relative 3D motion of the contact point on the two surfaces in mutual contact. The model produces expressions for three friction loads: slide force, roll torque, and spin torque. The cornerstone of the methodology is the process of tracking the evolution/path of the contact point on the surface of the two bodies in mutual contact. The salient attribute of the model lies with its ability to simultaneously compute, in a 3D setup, the slide, roll, and spin friction loads for smooth bodies of arbitrary geometry while accounting for both static and kinematic friction coefficients.
Do external labor market incentives motivate CEOs to adopt more aggressive corporate tax reporting preferences

Building on recent theory, we find strong and robust evidence that external labor market incentives motivate CEOs to adopt more aggressive tax policies in order to improve firm performance and their own labor market value. In addition, we find that the tax aggressiveness-labor market incentives relation varies in the cross-section consistently with theory. We find that the relation is attenuated in industries for which the CEO has fewer outside employment options, and we find it to be amplified in industries for which competition for CEO talent is likely greatest, and also among CEOs estimated to have greater ability. Overall, our results suggest that the market for CEOs – an incentive device external to the firm – has a meaningful impact on corporate tax policy.
Financing the Next Silicon Valley

Silicon Valley’s success has led other regions to attempt their own high-tech transformations, yet most imitators have failed. Entrepreneurs may be in short supply in these “non-tech” regions, but some non-tech regions are home to high-quality entrepreneurs who relocate to Silicon Valley due to a lack of local financing for their start-ups. Non-tech regions must provide local finance to prevent entrepreneurial relocation and reap spillover benefits for their communities. This Article compares three possible sources of entrepreneurial finance—private venture capital, state-sponsored venture capital, and angel investor groups—and finds that angel groups have distinct advantages when it comes to funding innovation in non-tech regions. This entrepreneurial finance story is then supplemented by a “law and entrepreneurship” story—specifically, a look at securities laws that might impede optimal levels of angel group financing.
The Impact of Unemployment Insurance on Job Search: Evidence from Google Search Data

Job search is a key choice variable in theories of labor markets but is difficult to measure directly. We develop a job search activity index based on Google search data, the Google Job Search Index (GJSI). We validate the GJSI with both survey- and web-based measures of job search. Unlike those measures, the GJSI is high frequency, geographically precise, and available in real time. We demonstrate the GJSI’s utility by using it to study the effects of unemployment insurance policy changes between 2008 and 2014. We find no evidence of an economically meaningful effect of these changes on aggregate search.
The historical relational data model (HRDM) and algebra based on lifespans

Critical to the design of an historical database model is the representation of the “existence” of objects across the temporal dimension — for example, the “birth,” “death,” or “rebirth” of an individual, or the establishment or dis-establishment of a relationship. The notion of the “lifespan” of a database object is proposed as a simple framework for expressing these concepts. An object's lifespan is simply those periods of time during which the database models the properties of that object. In this paper we propose the historical relational data model (HRDM) and algebra that is based upon lifespans and that views the values of all attributes as functions from time points to simple domains. The model that we obtain is a consistent extension of the relational data model, and provides a simple mechanism for providing both time-varying data and time-varying schemes.
Clarifying Consent: Peter Westen’s the Logic of Consent

This is a review essay of Peter Westen's "The Logic of Consent". I argue that Westen's book is philosophically informed, legally grounded, and well argued. It is a must-read for rape reformers, and yet it does not, itself, seek to reform rape laws. Rather, Westen's project is one of conceptual clarification. As Westen tells us in the Preface, we cannot resolve the justice of statutes regarding offenses of non-consent without first clarifying to ourselves and to others the diverse and potentially deceptive meanings of consent. In the first part of the review, I canvass Westen's delineation of the four different conceptions of consent, and argue that Westen succeeds in tracking our diverse and deceptive usages of consent. I then set forth two examples of Westen's achievement in separating normative, conceptual, and empirical arguments that occur within Westen's broader conceptions. The vast majority of Westen's arguments are devoted to individual debates within rape law, and thus, if "The Logic of Consent" lacks anything, it is a sense of perspective. In the second part of the review, I seek to place Westen's arguments in context. First, I argue that Westen's arguments demonstrate that consent is a species of choice, and its normative force is dependent upon its voluntariness. I contend that consent thus parallels our other assessment of choice within criminal law - choices by which we hold defendants criminally responsible. Secondly, I set forth the relationship between Westen's conceptions of consent. I argue that, with one exception, these conceptions do not compete; we simply conflate them. I then claim that the logical conclusion of Westen's own argument is that the law should jettison the one truly competing conception.
The Concept of "Religion" in the Supreme Court of Israel

In this Article, I suggest that “religion,” both as it is commonly understood, and as it is understood and applied by courts as a legal term of art, refers chiefly to belief, and that this understanding of “religion” is incorrectly, if tacitly, assumed to be both neutral and broadly applicable. I focus on three leading cases in the Supreme Court of Israel addressing the question “who is a Jew?” As Judaism is the dominant religion in Israel, how Israeli courts understand “who is a Jew” in a legal context says a great deal about how the Court understands “religion” more generally. The Court’s discussion reveals factors that the courts would find relevant in deciding what makes a religion a religion. I explore how this question has been answered and what the shape of the legal discourse has been in responding to that question, what assumptions have been made, and what factors have been determinative. The Article concludes that the Court has imported a Christian understanding of “religion” into Israeli civil jurisprudence under the mistaken assumption that such an understanding of religion is “secular.” It then asks how such an understanding could come to be seen as universal, and suggests that while conceiving of religion as belief fits neatly in the context of Christian Europe, in which religion was subordinated to the state, both the idea of religion as belief and the separability of religion from the temporal political authority of the modern state present greater difficulties in the context of the Jewish experience.
Interpretation in Law - Toward a Reconstruction of the Current Debate

Recent scholarship on interpretive problems in law has evidenced a struggle between two competing conceptions of linguistic meaning. Those arguing for the possibility of "objective" interpretation of juridical concepts see their task as saving law from the clutches of nihilism. Specifically, theorists of objectivity maintain that an interpreter of legal materials is not free to fashion meaning out of whole cloth, but is constrained by interpretive rules constitutive of the interpretive process. Those discounting the possibility of objective interpretation point to the radical indeterminancy of legal texts; for them the interpretation of legal concepts is little more than the imposition of power under the guise of "neutral interpretation."
Disability Screening and Labor Supply: Evidence from South Africa.

Yet research that examines the poverty reduction and labor supply effects of disability programs has taken place exclu-sively in developed countries with relatively low unemployment and high labor force participa-tion rates. In developing countries with high unemployment rates, the disincentive effect of cash transfers on labor supply has often been assumed to be economically insignificant (Anne Case and Angus Deaton 1998). In this paper, I provide initial evidence on, and draw attention to, the effect of the South Africa Disability Grant (DG) program on labor supply, in the context of a policy change in disability screening. I use a difference-in-differences estimator to assess the effect of a change toward a less intensive dis-ability screening on labor force nonparticipation for older individuals.If screening for disability benefit programs were perfect, the supply of disability benefits would be independent of labor supply decisions, and only those unable to work due to health con-ditions would receive benefits. However, the dis-ability screening process is imperfect because it is, in practice, difficult to determine whether a person is able to work, which is the typical test of eligibility for disability benefit programs. Recent evidence suggests that the work disincen -tive effects of disability benefits are expected to
A New Keynesian Workbook

Abstract A large literature has recently developed to place the New Keynesian framework for analyzing business cycle fluctuations and the conduct of monetary policy into undergraduate economics curricula. New Keynesian models offer several attractive modeling aspects: straightforward linear specifications of structural relations, intuitive and clear dynamic properties, derivation from microfoundations. This paper provides a description of an Excel-based application that presents several versions of the New Keynesian model: static, with adaptive expectations, and with rational expectations. The latter two versions also provide dynamic descriptions of variables’ evolution in terms of impulse response functions.
Performance Measurement in Corporate Governance: Do Mergers Improve Managerial Performance in the Post‐Merger Period?

Corporate finance studies of mergers and acquisitions have relied mostly on stock price reactions to evaluate the impact of these events. In this paper, we analyze the performance of a sample of merged firms over a ten year period using a managerially controlled efficiency measure, data envelopment analysis (DEA). Our individual firm‐level year‐by‐year analyses indicate that the managerial performance of the merged firms generally improved in the post‐merger period as documented in the earlier studies of mergers and acquisitions. However, there were also a significant number of cases where we could not observe improved managerial efficiency using this less aggregated approach. We conclude that DEA based disaggregated approaches are useful tools in the hands of corporate governance boards with an interest in yearly or even quarterly managerial performance at the individual firm level.
Corporate Victims of "Victimless Crime": How the FCPA's Statutory Ambiguity, Coupled with Strict Liability, Hurts Businesses and Discourages Compliance

The Foreign Corrupt Practices Act (“FCPA”), a federal law that outlaws corporate bribery of foreign officials, is the key legislation in the fight against global corruption. Unfortunately, despite the long-awaited guidance recently issued by the Department of Justice, the unpredictability and severity of FCPA enforcement, coupled with the lack of an affirmative defense in cases of adequate compliance, continues to take a substantial toll on U.S. businesses and the economy. This Note argues against strict corporate vicarious liability and evaluates the unintended effects of a broad interpretation of the FCPA on international business practices. Suggesting that current enforcement practices might actually reduce compliance, this Note evaluates several proposed solutions and advocates for a hybrid approach that would resolve the ambiguity and make compliance both feasible and economically viable. Bribing foreign officials is wrong, but not everything governments do to prevent it is wise or proportional.
Does price matter in charitable giving? Evidence from a large-scale natural field experiment

We conducted a natural field experiment to further our understanding of the economics of charity. Using direct mail solicitations to over 50,000 prior donors of a nonprofit organization, we tested the effectiveness of a matching grant on charitable giving. We find that the match offer increases both the revenue per solicitation and the response rate. Larger match ratios (i.e.,$3:$1 and $2:$1) relative to a smaller match ratio ($1:$1) had no additional impact, however. The results provide avenues for future empirical and theoretical work on charitable giving, cost-benefit analysis, and the private provision of public goods.
The Neo-Positivist Concept of International Law

The question "Is international law really law?” has not proved troublesome, according to Hart, because "a trivial question about the meaning of words has been mistaken for a serious question about the nature of things." Hart defends international law in Bentham's terms as "sufficiently analogous" to municipal law. It is important to see in what way this analogy is viewed by Hart in order to determine whether the reasoning he offers is too high a price to pay for accepting a neo-positivist into the circle of those who hold that international law is really law. Tags: Rule of Recognition, Sovereignty, Neo-Positivism, International Law, Basic norm in international law,
Optimal supply chain network design and redesign at minimal total cost and with demand satisfaction

In this paper, we propose a framework for supply chain network design and redesign that allows for the determination of the optimal levels of capacity and operational product flows associated with supply chain activities of manufacturing, storage, and distribution at minimal total cost and subject to the satisfaction of product demands. We formulate both the design and redesign problems as variational inequalities and show that the same algorithm, which exploits the underlying network structure, can be used for the solution of either problem. We illustrate the new framework with numerical examples that demonstrate the practicality and flexibility of the approach.
Government Interference and the Efficiency of the Land Market in China

Municipal governments in China established direct control of the supply of urban land in August 2004. This paper examines whether this government action mitigates the efficiency of the residential land market. Using a unique data set of detailed land and residential community transactions with manually collected location information for residential land lots in seven Chinese cities, this paper analyzes the relationship between the land lease prices and residential property prices from the first quarter of 2001 to the fourth quarter of 2007. Results indicate that property prices determined land prices both before and after 2004:3, but the effect was significantly weaker after 2004:3. This is consistent with the hypothesis that the market for residential land became less efficient after municipal governments gained direct control of the land supply.
Policy Responses to Balance-of-Payments Crises: The Role of Elections

Governments have a number of policy tools that can be used to address pressure on the balance of payments, threatening an undesirable decline in the relative value of the national currency. They can: (1) sell reserves, (2) raise interest rates, (3) impose capital controls, (4) apply trade restrictions, or (5) depreciate the currency. While researchers typically analyze these policies in isolation from one another, we treat them as a menu of options available to election-minded politicians. We analyze the use of these five policy responses to payments difficulties for a large sample of countries since the early 1970s. We argue that governments try to minimize political costs by adopting less transparent policies first and only moving to more visible policies as necessary, delaying the most visible and politically costly policies until after elections. The evidence is consistent with these claims: governments are more likely to draw down reserves and impose capital controls before other options. If these policies do not succeed, they tend to raise interest rates. If further action is needed, they delay devaluations and trade protection until after elections.
When Managers Bypass Shareholder Approval of Board Appointments: Evidence from the Private Security Market

Abstract This paper investigates the influence of managerial entrenchment on private placements by examining the firm's decision to appoint representatives of the private investors to the board without shareholder approval. By analyzing a sample of U.S. firms that appoint directors in combination with private offerings between 1995 and 2000, we find that firms with greater managerial entrenchment are more likely to bypass shareholder approval. Firms that bypass shareholders are less likely to appoint independent directors or to elect one of these directors as chairman. We also show that the market reacts more positively to the private offering announcement when the firm submits its board candidates for shareholder approval. Further, firms that bypass approval underperform compared to firms that obtain it. Overall our findings suggest that managers avoid shareholder approval to perpetuate entrenchment.
Protecting the borrower: An experiment in colonial India ☆

Abstract We study the impact of the Deccan Agriculturists' Relief Act (DARA), a key legislation to protect debtors that was enacted in western colonial India. Using a panel dataset and a difference-in-difference estimation, we find a substantial short-run decline in mortgage-backed credit after the passage of DARA. The contraction in credit did not reduce cropped area or agricultural investments in bullocks and carts, but may have led to less intensive cultivation.