cssi/SciSciGPT-SciSciNet huggingface dataset:
STELLAR ACTIVITY MIMICS A HABITABLE-ZONE PLANET AROUND KAPTEYN’S STAR

Kapteyn's star is an old M subdwarf believed to be a member of the Galactic halo population of stars. A recent study has claimed the existence of two super-Earth planets around the star based on radial velocity (RV) observations. The innermost of these candidate planets—Kapteyn b (P = 48 days)—resides within the circumstellar habitable zone (HZ). Given recent progress in understanding the impact of stellar activity in detecting planetary signals, we have analyzed the observed HARPS data for signatures of stellar activity. We find that while Kapteyn's star is photometrically very stable, a suite of spectral activity indices reveal a large-amplitude rotation signal, and we determine the stellar rotation period to be 143 days. The spectral activity tracers are strongly correlated with the purported RV signal of "planet b," and the 48-day period is an integer fraction () of the stellar rotation period. We conclude that Kapteyn b is not a planet in the HZ, but an artifact of stellar activity.
Exact partition potential for model systems of interacting electrons in 1-D

We find the numerically exact partition potential for 1-D systems of interacting electrons designed to model diatomic molecules. At integer fragment occupations, the kinetic contribution to the partition potential develops sharp features in the internuclear region that nearly cancel corresponding features of exchange-correlation. They occur at locations that coincide with those of well-known features of the underlying molecular Kohn–Sham potential. For non-integer fragment occupations, we demonstrate that the fragment energy gaps determine the kinetic part of the partition potential. Our results highlight the importance of non-additive noninteracting kinetic and exchange-correlation energy approximations in density-embedding methods at large internuclear separations and the importance of non-additive noninteracting kinetic energy approximations at all separations.
Quantized VCG Mechanisms for Polymatroid Environments

Many network resource allocation problems can be viewed as allocating a divisible resource, where the allocations are constrained to lie in a polymatroid. We consider market-based mechanisms for such problems. Though the Vickrey-Clarke-Groves (VCG) mechanism can provide the efficient allocation with strong incentive properties (namely dominant strategy incentive compatibility), its well-known high communication requirements can prevent it from being used. There have been a number of approaches for reducing the communication costs of VCG by weakening its incentive properties. Here, instead we take a different approach of reducing communication costs via quantization while maintaining VCG's dominant strategy incentive properties. The cost for this approach is a loss in efficiency which we characterize. We first consider quantizing the resource allocations so that agents need only submit a finite number of bids instead of full utility function. We subsequently consider quantizing the agent's bids.
Bulk hydrodynamic stability and turbulent saturation in compressing hot spots

For hot spots compressed at constant velocity, we give a hydrodynamic stability criterion that describes the expected energy behavior of non-radial hydrodynamic motion for different classes of trajectories (in ρR — T space). For a given compression velocity, this criterion depends on ρR, T, and dT/d(ρR) (the trajectory slope) and applies point-wise so that the expected behavior can be determined instantaneously along the trajectory. Among the classes of trajectories are those where the hydromotion is guaranteed to decrease and those where the hydromotion is bounded by a saturated value. We calculate this saturated value and find the compression velocities for which hydromotion may be a substantial fraction of hot-spot energy at burn time. The Lindl (Phys. Plasmas 2, 3933 (1995)] “attractor” trajectory is shown to experience non-radial hydrodynamic energy that grows towards this saturated state. Comparing the saturation value with the available detailed 3D simulation results, we find that the fluctuating velocities in these simulations reach substantial fractions of the saturated value.For hot spots compressed at constant velocity, we give a hydrodynamic stability criterion that describes the expected energy behavior of non-radial hydrodynamic motion for different classes of trajectories (in ρR — T space). For a given compression velocity, this criterion depends on ρR, T, and dT/d(ρR) (the trajectory slope) and applies point-wise so that the expected behavior can be determined instantaneously along the trajectory. Among the classes of trajectories are those where the hydromotion is guaranteed to decrease and those where the hydromotion is bounded by a saturated value. We calculate this saturated value and find the compression velocities for which hydromotion may be a substantial fraction of hot-spot energy at burn time. The Lindl (Phys. Plasmas 2, 3933 (1995)] “attractor” trajectory is shown to experience non-radial hydrodynamic energy that grows towards this saturated state. Comparing the saturation value with the available detailed 3D simulation results, we find that the fluctuating ...
Lunar Secondary Craters and Estimated Ejecta Block Sizes Reveal a Scale-Dependent Fragmentation Trend

Planetary impact events eject large volumes of surface material. Crater excavation processes are difficult to study, and in particular the details of individual ejecta fragments are not well understood. A related, enduring issue in planetary mapping is whether a given crater resulted from a primary impact (asteroid or comet) or instead is a secondary crater created by an ejecta fragment. With mapping and statistical analyses of six lunar secondary crater fields (including Orientale, Copernicus, and Kepler) we provide three new constraints on these issues: 1) estimation of the maximum secondary crater size as a function of distance from a primary crater on the Moon, 2) estimation of the size and velocity of ejecta fragments that formed these secondaries, and 3) estimation of the fragment size ejected at escape velocity. Through this analysis, we confirmed and extended a suspected scale-dependent trend in ejecta size-velocity distributions. Maximum ejecta fragment sizes fall off much more steeply with increasing ejection velocity for larger primary impacts (compared to smaller primary impacts). Specifically, we characterize the maximum ejecta sizes for a given ejection velocity with a power law, and find the velocity exponent varies between approximately -0.3 and -3 for the range of primary craters investigated here (0.83-660 km in diameter). Data for the jovian moons Europa and Ganymede confirm similar trends for icy surfaces. This result is not predicted by analytical theories of formation of Grady-Kipp fragments or spalls during impacts, and suggests that further modeling investigations are warranted to explain this scale-dependent effect.
Stochastic Defense Against Complex Grid Attacks

We describe stochastic defense mechanisms designed to detect sophisticated grid attacks involving both physical actions (including load modification) and sensor output alteration. The initial attacks are undetectable under a full ac power-flow model even assuming ubiquitous sensor placement, while hiding large line overloads. The defensive techniques apply network control actions that change voltages in a random fashion and additionally introduce (random) low-rank corrections to covariance matrices.
Photon detection system designs for the Deep Underground Neutrino Experiment

The Deep Underground Neutrino Experiment (DUNE) will be a premier facility for exploring long-standing questions about the boundaries of the standard model. Acting in concert with the liquid argon time projection chambers underpinning the far detector design, the DUNE photon detection system will capture ultraviolet scintillation light in order to provide valuable timing information for event reconstruction. To maximize the active area while maintaining a small photocathode coverage, the experiment will utilize a design based on plastic light guides coated with a wavelength-shifting compound, along with silicon photomultipliers, to collect and record scintillation light from liquid argon. This report presents recent preliminary performance measurements of this baseline design and several alternative designs which promise significant improvements in sensitivity to low-energy interactions.
The State of the Heliosphere Revealed by Limb-halo Coronal Mass Ejections in Solar Cycles 23 and 24

We compare the properties of halo coronal mass ejections (CMEs) that originate close to the limb (within a central meridian distance range of 60 to 90 deg) during solar cycles 23 and 24 to quantify the effect of the heliospheric state on CME properties. There are 44 and 38 limb halos in the cycles 23 and 24, respectively. Normalized to the cycle-averaged total sunspot number, there are 42 percent more limb halos in cycle 24. Although the limb halos as a population is very fast (average speed 1464 km s-1), cycle-24 halos are slower by 26 percent than the cycle-23 halos. We introduce a new parameter, the heliocentric distance of the CME leading edge at the time a CME becomes a full halo; this height is significantly shorter in cycle 24 (by 20 percent) and has a lower cutoff at 6 Rs. These results show that cycle-24 CMEs become halos sooner and at a lower speed than the cycle-23 ones. On the other hand, the flare sizes are very similar in the two cycles, ruling out the possibility of eruption characteristics contributing to the differing CME properties. In summary, this study reveals the effect of the reduced total pressure in the heliosphere that allows cycle-24 CMEs expand more and become halos sooner than in cycle 23. Our findings have important implications for the space-weather consequences of CMEs in cycle 25 (predicted to be similar to cycle 24) and for understanding the disparity in halo counts reported by automatic and manual catalogs.
On Many-Body Localization for Quantum Spin Chains

For a one-dimensional spin chain with random local interactions, we prove that many-body localization follows from a physically reasonable assumption that limits the amount of level attraction in the system. The construction uses a sequence of local unitary transformations to diagonalize the Hamiltonian and connect the exact many-body eigenfunctions to the original basis vectors.
Lifting of level-1 states in the D1D5 CFT

The D1D5 CFT has a large set of states that are supersymmetric at the ‘free’ orbifold point in moduli space. When we perturb away from this point, some of these states join into long multiplets and lift in energy, while others remain supersymmetric. The count of unlifted states can be bounded below by an index, but the index does not yield the pattern of lifting; i.e., which states join into a long multiplet and how much this multiplet lifts. In this paper we consider the simple case of the D1D5 CFT where the orbifold CFT is a sigma model with targets space (T4)2/S2 and consider states at energy level 1. There are 2688 states at this level. The lifted states form a triplet of long multiplets, and we compute their lift at second order in perturbation theory. Half the members of the long multiplet are in the untwisted sector and half are in the twisted sector. This and other similar studies should help in the understanding of fuzzball states that describe extremal holes, since CFT sectors with low twist describe shallow throats in the dual gravity solution while sectors with high twist describe deep throats.
Virtual testbed for monocular visual navigation of small unmanned aircraft systems

Monocular visual navigation methods have seen significant advances in the last decade, recently producing several real-time solutions for autonomously navigating small unmanned aircraft systems wit...
Simulations of Solar Jets Confined by Coronal Loops

Coronal jets are collimated, dynamic events that occur over a broad range of spatial scales in the solar corona. In the open magnetic field of coronal holes, jets form quasi-radial spires that can extend far out into the heliosphere, while in closed-field regions the jet outflows are confined to the corona. We explore the application of the embedded-bipole model to jets occurring in closed coronal loops. In this model, magnetic free energy is injected slowly by footpoint motions that introduce twist within the closed dome of the jet source region, and is released rapidly by the onset of an ideal kink-like instability. Two length scales characterize the system: the width (N) of the jet source region and the footpoint separation (L) of the coronal loop that envelops the jet source. We find that both the conditions for initiation and the subsequent dynamics are highly sensitive to the ratio L/N. The longest-lasting and most energetic jets occur along long coronal loops with large L/N ratios, and share many of the features of open-field jets, while smaller L/N ratios produce shorter-duration, less energetic jets that are affected by reflections from the far-loop footpoint. We quantify the transition between these behaviors and show that our model replicates key qualitative and quantitative aspects of both quiet Sun and active-region loop jets. We also find that the reconnection between the closed dome and surrounding coronal loop is very extensive: the cumulative reconnected flux at least matches the total flux beneath the dome for small L/N, and is more than double that value for large L/N.
Motility-driven glass and jamming transitions in biological tissues.

Understanding metastatic cell escape from tumors and embryonic development requires a detailed understanding of how cells move collectively inside dense tissues. Scientists show that small changes to single-cell behavior can cause tissue to transition between a fluidlike and a solidlike state.
Ricci-positive metrics on connected sums of projective spaces

Abstract It is a well known result of Gromov that all manifolds of a given dimension with positive sectional curvature are subject to a universal bound on the sum of their Betti numbers. On the other hand, there is no such bound for manifolds with positive Ricci curvature: indeed, Perelman constructed Ricci positive metrics on arbitrary connected sums of complex projective planes. In this paper, we revisit and extend Perelman's techniques to construct Ricci positive metrics on arbitrary connected sums of complex, quaternionic, and octonionic projective spaces in every dimension.
METHODS FOR ESTIMATING FLUXES AND ABSORPTIONS OF FAINT X-RAY SOURCES

X-ray sources with very few counts can be identified with low-noise X-ray detectors such as the Advanced CCD Imaging Spectrometer on board the Chandra X-ray Observatory. These sources are often too faint for parametric spectral modeling using well-established methods such as fitting with XSPEC. We discuss the estimation of apparent and intrinsic broadband X-ray fluxes and soft X-ray absorption from gas along the line of sight to these sources, using nonparametric methods. Apparent flux is estimated from the ratio of the source count rate to the instrumental effective area averaged over the chosen band. Absorption, intrinsic flux, and errors on these quantities are estimated from comparison of source photometric quantities with those of high signal-to-noise spectra that were simulated using spectral models characteristic of the class of astrophysical sources under study. The concept of this method is similar to the long-standing use of color-magnitude diagrams in optical and infrared astronomy, with X-ray median energy replacing color index and X-ray source counts replacing magnitude. Our nonparametric method is tested against the apparent spectra of ~2000 faint sources in the Chandra observation of the rich young stellar cluster in the M 17 H II region. We show that the intrinsic X-ray properties can be determined with little bias and reasonable accuracy using these observable photometric quantities without employing often uncertain and time-consuming methods of nonlinear parametric spectral modeling. Our method is calibrated for thermal spectra characteristic of stars in young stellar clusters, but recalibration should be possible for some other classes of faint X-ray sources such as extragalactic active galactic nuclei.
3D Integration: Another Dimension Toward Hardware Security

We review threats and selected schemes concerning hardware security at design and manufacturing time as well as at runtime. We find that 3D integration can serve well to enhance the resilience of different hardware security schemes, but it also requires thoughtful use of the options provided by the umbrella term of 3D integration. Toward enforcing security at runtime, we envision secure 2.5D system-level integration of untrusted chips and “all around” shielding for 3D ICs.
PRODUCT INTEGRALS AND WILSON LOOPS

Using product integrals we review the unambiguous mathematical representation of Wilson line and Wilson loop operators, including their behavior under gauge transformations and the non-abelian Stokes theorem. Interesting consistency conditions among Wilson lines are also presented.
The APOKASC Catalog

I report on the APOKASC catalog, a joint effort between the Kepler Asteroseismic Science Consortium and the SDSS-III APOGEE spectroscopic survey. It will contain both seismic and spectroscopic values for stars observed by both surveys. I discuss the derivation of spectroscopic parameters and their uncertainties from the H-band spectra delivered by the APOGEE spectrograph, illustrating the sensitivity of stellar spectra to some parameters, such as Teff, and lack of sensitivity to others, such as logg.
An Area Law for One Dimensional Quantum Systems

We prove an area law for the entanglement entropy in gapped one-dimensional quantum systems. The bound on the entropy grows surprisingly rapidly with the correlation length; we discuss this in terms of properties of quantum expanders and present a conjecture on matrix product states which may provide an alternate way of arriving at an area law. We also show that, for gapped, local systems, the bound on Von Neumann entropy implies a bound on Renyi entropy for sufficiently large α<1 and implies the ability to approximate the ground state by a matrix product state.
Nuclear Ignition of White Dwarf Stars by Relativistic Encounters with Rotating Intermediate Mass Black Holes

We present results from general relativistic calculations of nuclear ignition in white dwarf stars triggered by near encounters with rotating intermediate mass black holes with different spin and alignment parameters. These encounters create thermonuclear environments characteristic of Type Ia supernovae capable of producing both calcium and iron group elements in arbitrary ratios, depending primarily on the proximity of the interaction which acts as a strong moderator of nucleosynthesis. We explore the effects of black hole spin and spin-orbital alignment on burn product synthesis to determine whether they might also be capable of moderating reactive flows. When normalized to equivalent impact penetration, accounting for frame dragging corrections, the influence of spin is weak, no more than 25% as measured by nuclear energy release and mass of burn products, even for near maximally rotating black holes. Stars on prograde trajectories approach closer to the black hole and produce significantly more unbound debris and iron group elements than is possible by encounters with nonrotating black holes or by retrograde orbits, at more than 50% mass conversion efficiency. The debris contains several radioisotopes, most notably Ni56, made in amounts that produce sub-luminous (but still observable) light curves compared to branch-normal SNe Ia.
ON THE METRIC ENTROPY OF THE BANACH–MAZUR COMPACTUM

We study the metric entropy of the metric space unitary matrices known as “quantum expanders”.
Interferometry of non-Abelian anyons

We develop the general quantum measurement theory of non-Abelian anyons through interference experiments. The paper starts with a terse introduction to the theory of anyon models, focusing on the basic formalism necessary to apply standard quantum measurement theory to such systems. This is then applied to give a detailed analysis of anyonic charge measurements using a Mach–Zehnder interferometer for arbitrary anyon models. We find that, as anyonic probes are sent through the legs of the interferometer, superpositions of the total anyonic charge located in the target region collapse when they are distinguishable via monodromy with the probe anyons, which also determines the rate of collapse. We give estimates on the number of probes needed to obtain a desired confidence level for the measurement outcome distinguishing between charges, and explicitly work out a number of examples for some significant anyon models. We apply the same techniques to describe interferometry measurements in a double point-contact interferometer realized in fractional quantum Hall systems. To lowest order in tunneling, these results essentially match those from the Mach–Zehnder interferometer, but we also provide the corrections due to processes involving multiple tunnelings. Finally, we give explicit predictions describing state measurements for experiments in the Abelian hierarchy states, the non-Abelian Moore–Read state at v = 5/2 and Read–Rezayi state at v = 12/5.
Bubbles unbound II: AdS and the single bubble

I present further analytic time symmetric initial data for five dimensions describing ``bubbles of nothing'' which have no Kaluza-Klein circle asymptotically. The new solutions consist of a large family of single bubbles in both asymptotically flat and asymptotically AdS space. I also numerically construct gravitational solitons in AdS where the usual boundary conditions are modified geometrically but not topologically. Furthermore I point out there are both regular AdS bubbles and topologically trivial metrics in asymptotically global AdS dual to matter which violates all the usual energy conditions, both classical and quantum. I inquire as to the existence of a dual gravitational instability.
Powerful extragalactic jets dissipate their kinetic energy far from the central black hole

Accretion onto the supermassive black hole in some active galactic nuclei (AGN) drives relativistic jets of plasma, which dissipate a significant fraction of their kinetic energy into gamma-ray radiation. The location of energy dissipation in powerful extragalactic jets is currently unknown, with implications for particle acceleration, jet formation, jet collimation, and energy dissipation. Previous studies have been unable to constrain the location between possibilities ranging from the sub-parsec-scale broad-line region to the parsec-scale molecular torus, and beyond. Here we show using a simple diagnostic that the more distant molecular torus is the dominant location for powerful jets. This diagnostic, called the seed factor, is dependent only on observable quantities, and is unique to the seed photon population at the location of gamma-ray emission. Using 62 multiwavelength, quasi-simultaneous spectral energy distributions of gamma-ray quasars, we find a seed factor distribution which peaks at a value corresponding to the molecular torus, demonstrating that energy dissipation occurs ~1 parsec from the black hole (or ~104 Schwarzchild radii for a 109M⊙ black hole). The location of energy dissipation in powerful extragalactic jets is currently unknown. Here, the authors show that the more distant molecular torus is the dominant location for powerful jets using a diagnostic called the seed factor which is dependent only on observable quantities.
The Mixed Problem for the Laplacian in Lipschitz Domains

We consider the mixed boundary value problem, or Zaremba’s problem, for the Laplacian in a bounded Lipschitz domain Ω in R n , n ≥ 2. We decompose the boundary $ \partial \Omega= D\cup N$ with D and N disjoint. The boundary between D and N is assumed to be a Lipschitz surface in $\partial \Omega$ . We find an exponent q 0 > 1 so that for p between 1 and q 0 we may solve the mixed problem for L p . Thus, if we specify Dirichlet data on D in the Sobolev space W 1,p (D) and Neumann data on N in L p (N), the mixed problem with data f D and f N has a unique solution and the non-tangential maximal function of the gradient lies in $L^p( \partial \Omega)$ . We also obtain results for p = 1 when the data comes from Hardy spaces.
Subconvexity and equidistribution of Heegner points in the level aspect

Let q be a prime and -D < -4 be an odd fundamental discriminant such that q splits in Q(\sqrt{-D}). For f a weight zero Hecke-Maass newform of level q and h the weight one theta series of level D corresponding to an ideal class group character of Q(\sqrt{-D}), we establish a hybrid subconvexity bound for L(f \times h,s) at the central point when q = D^{\eta} for 0 < \eta < 1. With this circle of ideas, we show that the Heegner points of level q and discriminant D become equidistributed, in a natural sense, as q, D become large with q < D^{1/20-\varepsilon}. Our approach to these problems is connected to estimating the L^2-restriction norm of a Maass form of large level when restricted to the collection of Heegner points. We furthermore establish bounds for quadratic twists of Hecke-Maass L-functions with simultaneously large level and large quadratic twist, and hybrid bounds for quadratic Dirichlet L-functions in certain ranges.
Computing knot Floer homology in cyclic branched covers

We use grid diagrams to give a combinatorial algorithm for computing the knot Floer homology of the pullback of a knot K in its m-fold cyclic branched cover Sigma^m(K), and we give computations when m=2 for over fifty three-bridge knots with up to eleven crossings.
ArborX: A Performance Portable Geometric Search Library

Searching for geometric objects that are close in space is a fundamental component of many applications. The performance of search algorithms comes to the forefront as the size of a problem increases both in terms of total object count as well as in the total number of search queries performed. Scientific applications requiring modern leadership-class supercomputers also pose an additional requirement of performance portability, i.e., being able to efficiently utilize a variety of hardware architectures. In this article, we introduce a new open-source C++ search library, ArborX, which we have designed for modern supercomputing architectures. We examine scalable search algorithms with a focus on performance, including a highly efficient parallel bounding volume hierarchy implementation, and propose a flexible interface making it easy to integrate with existing applications. We demonstrate the performance portability of ArborX on multi-core CPUs and GPUs and compare it to the state-of-the-art libraries such as Boost.Geometry.Index and nanoflann.
LMVE at SemEval-2020 Task 4: Commonsense Validation and Explanation Using Pretraining Language Model

This paper introduces our system for commonsense validation and explanation. For Sen-Making task, we use a novel pretraining language model based architecture to pick out one of the two given statements that is againstcommon sense. For Explanation task, we use a hint sentence mechanism to improve the performance greatly. In addition, we propose a subtask level transfer learning to share information between subtasks.
Universal fast flux control of a coherent, low-frequency qubit

A set of protocols for initializing, controlling, and reading out a qubit design known as ``heavy fluxonium,'' operated in a previously unexplored regime, provides excellent coherence times and fast high-fidelity gates.
CAPITAL ALLOCATION AND DELEGATION OF DECISION-MAKING AUTHORITY WITHIN FIRMS

Abstract We use a unique data set that contains information on more than 1,000 Chief Executive Officers (CEOs) and Chief Financial Officers (CFOs) around the world to investigate the degree to which executives delegate financial decisions and the circumstances that drive variation in delegation. Delegation does not appear to be monolithic; instead, our results show that it varies across corporate policies and also varies with the personal characteristics of the CEO. We find that CEOs delegate financial decisions for which they need the most input, when they are overloaded, and when they are distracted by recent acquisitions. CEOs delegate less when they are knowledgeable (long-tenured or with a finance background). Capital is allocated based on “gut feel” and the personal reputation of the manager running a given division. Finally, corporate politics and corporate socialism affect capital allocation in European and Asian firms.
Ethical Limitations on the State's Use of Arational Persuasion

Policy makers frequently use arational appeals and nudges—such as those relying on emotion, cognitive biases, and subliminal messaging—to persuade citizens to adopt behaviors that support public goals. However, these communication tactics have been widely criticized for relying on arational triggers rather than reasoned argument. This article develops a fuller account of the nonconsequentialist objection to arational persuasion by state actors, focusing on theories of decisional autonomy and metadecisional voluntariness. The article concludes by proposing ethically justifiable limitations on state communications that should be compelling to both critics and advocates of arational persuasion.
Information interpretation or information discovery: which role of analysts do investors value more?

This study provides evidence that a significant percentage of analyst forecast revisions are issued promptly after a broad set of corporate public disclosures and that investors perceive these prompt revisions as more valuable than nonprompt revisions. These results hold for all revisions, revisions outside of the earnings announcement window, or revisions in weeks preceding the earnings announcements and are also robust to various sensitivity tests. Investors particularly value analysts’ prompt interpretation of earnings announcements, Form 8-K filings, or certain qualitative news. To the extent that prompt revisions are more likely to reflect analysts’ information interpretation role, our results suggest that investors value more highly analysts’ ability to interpret public disclosures, especially less structured or non-financial disclosures, than their ability for information discovery.
Appraising the “Merger Price” Appraisal Rule

This paper develops an auction design framework to analyze various methods for assessing “fair value” in post-merger appraisal proceedings. Our inquiry spotlights an approach recently embraced by some courts benchmarking fair value against the merger price itself. We show that the merger price deference effectively nullifies the role that appraisal can potentially play in establishing a de facto reserve price for company auctions, thereby depressing both acquisition prices and target shareholders’ expected welfare relative to both the optimal appraisal policy and a variety of other valuation measures. We also examine conditions under which deference to the merger price may nonetheless be defensible on economic grounds. Our results have empirical implications for understanding appraisal, and they likewise help to inform doctrine by providing guidance to legal actors about when a sales process can be considered sufficiently “robust” to justify deal price deference.
Importance of Catering Incentives for Growth Dynamics

This paper tests whether the dynamics of firm growth metrics, such as sales and investment growth, are consistent with firms catering to the market by delivering growth when stock prices are more sensitive to growth-related news. After developing growth valuation premium measures, we document four main results consistent with catering theory. First, time periods of high growth premium are followed by higher-than-expected growth indicators. Second, catering to the premium is more pronounced for firms whose managers care more about maximizing short-term stock prices. Third, firms whose managers care more about short-term stock prices have higher time-series volatility of median sales, investment, and PPE growth. Finally, conditional trading strategy based on timing the revenue growth premium yields 26 basis points per month after adjusting for risk and postearnings announcement drift.
Hovering Too Close: The Ramifications of Helicopter Parenting in Higher Education

"They are needy, overanxious and sometimes plain pesky–and schools at every level are trying to find ways to deal with them. No, not students. Parents–specifically parents of today's "˜millennial generation' who, many educators are discovering, can't let their kids go."
Willingness to Pay versus Welfare

Economists often analyze questions of law and policy by reference to the criterion of private willingness to pay (WTP), with the belief that people's WTP for a good is an accurate proxy for the welfare that they would obtain from that good. For two reasons, the proxy is crude. The first problem is that people may not pay for all of the benefits they receive, and in such cases, use of WTP may lead in unfortunate directions, even or especially if welfare is our lodestar. Inefficient results may nonetheless increase welfare. The second and more fundamental problem is that people may be willing to pay for goods whose acquisition does not improve their welfare. People typically choose on the basis of their affective forecasting, and their affective forecasts can lead them to make bad blunders. Sometimes people overestimate the welfare effects of both losses and gains. These points have many implications for law and policy. In particular, juries are probably offering greatly inflated dollar awards for hedonic damages, and the outcome of cost-benefit analyses, based on WTP, may not capture welfare, suitably defined. The absence of a connection between increases in Gross Domestic Product and self-reported happiness is highly suggestive here.
Why Appellate Courts Have Rejected the Argument that the Defense of Marriage Act Trumps the Parental Kidnapping Prevention Act

This article explains why the Defense of Marriage Act should not be interpreted to trump the Parental Kidnapping Prevention Act. Using two cases from Virginia/Vermont and California/Alabama, the article discusses why PKPA protections should be available to couples in same-sex relationships despite contract language in DOMA.
The Role of Learning Support Services in University Students’ Educational Outcomes

Learning Support Services at the University of California, Santa Cruz is intended to aid students—particularly those who are at highest risk of academic failure—to master the required material and ...
Equipment investment and growth in developing countries

Abstract Differences in equipment investment or equipment prices account for large variations in growth rates across countries. An important task is to understand the economic mechanism underlying the equipment–growth nexus and its policy implications. In order to study this issue, this paper develops a model in which growth is driven by the adoption of technologies that are embodied in equipment. I show that this model can quantitatively account for the observed cross-country relationships between equipment investment, equipment prices, and growth. I find that the competitive equilibrium is characterized by inefficiently low levels of learning and too slow growth and study which policies are able to remedy this inefficiency.
The Reaction of Real Estate–Related Industries to the Monetary Policy Actions

We study the impact of changes in US monetary policy on the equity returns of real-estate-related industries. We find that over the 1989 to 2005 sample period covered in our study, a hypothetical unexpected rate cut of 25 basis points is associated with an increase of about 170 basis points in the value-weighted returns of real estate-related industries. We find that monetary policy impacts the stock prices in real estate-related industries through its impact on the future expected stock returns and not on real interest rates or expected future dividends. There is also some evidence of asymmetry in the responses of the industry returns to the monetary policy actions. A strong stock price response to reversals in the direction of the Federal Reserve’s monetary policy is reported.
Breaking the Barrier between Regionalism and Multilateralism: A New Perspective on Trade Regionalism

This article attempts to reconcile legal and institutional tensions between regionalism, in the form of regional trading agreements (RTAs), and multilateralism represented by the WTO. It observes that GATT Article XXIV alone cannot fully resolve such tensions and thus calls for a new paradigm to deal with RTAs and their interaction with the GATT/WTO system. A weak mandate from working groups and an impotent dispute settlement mechanism largely incapacitated the old GATT in its attempt to synchronize RTAs’ simultaneously protectionist and trade-generating effects, thereby rendering RTAs to have thrived in this lenient environment up until the creation of the WTO, which developed legal discipline, in both a legislative and jurisprudential context, to strengthen normative effects of Article XXIV. Yet this article further suggests that an entirely new vision is necessary to cope with those RTA-issues left untouched by Article XXIV, namely the unique problem of services (as distinguished from goods) and the operation (as opposed to formation) of RTAs in the WTO system. Premised upon the notion of convergence, the new paradigm proposed in this article focuses on the interdependent interactions between/among diverse trading units, such as RTAs and the WTO, in a pluralistic yet federalistic fashion. Convergence of this type would promote “open regionalism,” the assimilation by some trading units of the important features of others, and the alliance of differing trading units. Emerging from these converging interactions would be a common hermeneutical and institutional terrain necessary to rectify the current deficiencies of Article XXIV through the development of a jus gentium of international trade.
What Is Public Interest Law? Empirical Perspectives on an Old Question

This article presents some preliminary findings from empirical research on public discourse around public interest law. The research treats “public interest law” as a keyword – a phrase that assumes different meanings as it is mobilized by different social actors for different purposes. The article examines two public data sources in which conflict over the meaning of public interest law has been particularly visible: 1) advocacy groups’ self-characterization in U.S. Supreme Court briefs, and 2) accounts in two major newspapers. Together, these sources show that language that once applied to a relatively small number of organizations and practices serving a limited set of constituencies is now claimed by, and used to describe, a much larger set of organizations, actors, policy agendas, and political perspectives. These data also suggest that, during a period when conservative and libertarian groups have become increasingly assertive in claiming the public interest law designation, the media have used the term more cautiously. This struggle over discourse is integrally related to the allocation of some types of legitimacy and resources within the American legal profession. Moreover, it has significant consequences for judicial decision making and policy formation to the extent that public interest law organizations and lawyers exercise special influence tied to their perceived status as champions of underrepresented constituencies.
Justice, Access to the Courts, and the Right to Free Counsel for Indigent Parents: The Continuing Scourge of Lassiter v. Department of Social Services of Durham.

Nearly a century ago, legal services pioneer Reginald Heber Smith observed that “substantive law, however fair and equitable itself, is impotent to provide the necessary safeguards unless the administration of justice, which alone gives effect and force to substantive law, is in the highest sense impartial.”1 The expression of this lofty ideal introduced Smith’s sweeping indictment of the manner in which indigents seeking to enforce basic civil rights in the early twentieth century were routinely denied meaningful recourse to the courts: The administration of American justice is not impartial, the rich and the poor do not stand on an equality before the law, the traditional method of providing justice has operated to close the doors of the courts to the poor, and has caused a gross denial of justice in all parts of the country to millions of persons.2 Eighty-five years after Smith issued his indictment, gaps in the ability of our civil courts to achieve the ideal of fair and equitable administration of justice are more profound than ever.3 Plainly, no
Rationalizable Counterfactual Choice Probabilities in Dynamic Binary Choice Processes

We address two issues in nonparametric structural analyses of dynamic binary choice processes (DBCP). First, the DBCP is not testable and decision makers’ single-period payoffs (SPP) cannot be identified even when the distribution of unobservable states (USV) is known. Numerical examples show setting SPP from one choice to arbitrary utility levels to identify that from the other can lead to errors in predicting choice probabilities under counterfactual state transitions. We propose two solutions. First, if a data generating process (DGP) has exogenous variations in observable state transitions, the DBCP becomes testable and SPP is identified. Second, exogenous economic restrictions on SPP (such as ranking of states by SPP, or shape restrictions) can be used to recover the identified set of rationalizable counterfactual choice probabilities (RCCP) that are consistent with model restrictions. The other (more challenging) motivating issue is that when the USV distribution is not known, misspecification of the distribution in structural estimation leads to errors in counterfactual predictions. We introduce a simple algorithm based on linear programming to recover sharp bounds on RCCP. This approach exploits the fact that some stochastic restrictions on USV (such as independence from observable states) and economic restrictions on SPP can be represented (without loss of information for counterfactual analyses) as linear restrictions on SPP and distributional parameters of USV. We use numerical examples to illustrate the algorithm and show sizes of identified sets of RCCP can be quite small relative to the outcome space.
Market Entry and the Proper Scope of Copyright

Abstract The author presents a model of copyright law as a means to regulate entry into information markets. The model shows under what conditions copyright rules may lead to excessive or insufficient entry. The entry conditions are used to assess the efficacy of copyright rules in maximizing the sum of consumer and producer surplus.
Combat exposure and migraine headache: evidence from exogenous deployment assignment.

Migraine headache is a growing problem for U.S. servicemembers deployed to Iraq and Afghanistan and has been linked to substantial negative socioeconomic consequences. However, there has been no comprehensive examination of the relationship between combat exposure and migraine headache or its stress-related triggers. Analyzing data drawn from the National Longitudinal Study of Adolescent Health, we use exogenous variation in deployment assignment to estimate the effect of combat exposure on migraine headache. We find that those deployed to a combat zone with enemy firefight are at substantially increased risk for migraine headache relative to those deployed to non-combat zones outside the United States or to combat zones without enemy firefight. We find that combat-induced sleep disorders, stress-related psychological problems, and physical injuries in combat explain approximately 40-45 percent of the relationship between combat exposure and migraine headache. Language: en
Conflict between doctor and patient.

“The belief that doctors can act on behalf of patients denies the existence of inevitable conflict.” Jay Katz1
Strategy-proofness, investment efficiency, and marginal returns: an equivalence

The market design literature has successfully designed mechanisms that achieve desirable properties such as strategy-proofness (incentive compatibility) and efficiency at the allocation stage. However, agents must often make investment decisions before participating in allocation mechanisms. These decisions are endogenous, in the sense that market participants' investments depend on the choice of mechanism. The goal of this paper is to understand when it is possible to design fully efficient mechanisms, i.e., mechanisms that both are efficient ex post and induce agents to make efficient investment decisions ex ante. To do so, we consider a general public choice setting (with transfers). Our framework includes, but is not limited to, object allocation settings such as auctions as well as two-sided matching environments such as residency matching. In our setting, payoffs depend not only on the outcome selected by the mechanism but also on agents' pre-mechanism investment choices. We say that a mechanism induces efficient investment by an agent if the investment choices that maximize the utility of that agent coincide with the investment choices that maximize social welfare. Our first main result shows that a mechanism induces efficient investment if and only if it provides marginal rewards, in the sense that the change in an agent's utility when that agent adjusts her investment is equal to the associated change in social welfare. For our second main result, we focus on ex post efficient mechanisms, i.e., mechanisms that select welfare-maximizing outcomes given agents' investment decisions. We show that for ex post efficient mechanisms, inducing efficient investment and providing marginal rewards are both equivalent to strategy-proofness. We extend our equivalence results to approximate versions of the aforementioned properties. Our results imply that under the Kelso--Crawford (1982) worker-optimal stable mechanism (with discrete transfers), workers are incentivized to make approximately efficient human capital investments before entering the labor market (conditional on the actions of firms).
Expected Devaluation and Economic Fundamentals

Recent incidents of exchange rate collapse have provoked interest in the extent to which such events are determined by economic fundamentals. This paper considers whether interest rate differentials are appropriate measures of the risk of devaluation and whether this measure of devaluation risk reflects the movements of variables which capture internal and external balance. The paper finds that interest rate differentials reflect devaluation risk but that movements in fundamental variables have only a weak effect on devaluation risk in France and Italy. The most significant influence on devaluation risk is the position of the currency in its band in that the lower is the exchange value of a currency within the band, the greater is the perceived risk of devaluation.