cssi/SciSciGPT-SciSciNet huggingface dataset:
Scalable and Generalizable Social Bot Detection through Data Selection

Efficient and reliable social bot classification is crucial for detecting information manipulation on social media. Despite rapid development, state-of-the-art bot detection models still face generalization and scalability challenges, which greatly limit their applications. In this paper we propose a framework that uses minimal account metadata, enabling efficient analysis that scales up to handle the full stream of public tweets of Twitter in real time. To ensure model accuracy, we build a rich collection of labeled datasets for training and validation. We deploy a strict validation system so that model performance on unseen datasets is also optimized, in addition to traditional cross-validation. We find that strategically selecting a subset of training data yields better model accuracy and generalization than exhaustively training on all available data. Thanks to the simplicity of the proposed model, its logic can be interpreted to provide insights into social bot characteristics.
Effective resistance on graphs and the Epidemic quasimetric

We introduce the epidemic quasimetric on graphs and study its behavior with respect to clustering techniques. In particular we compare its behavior to known objects such as the graph distance, effective resistance, and modulus of curve families.
ON THE EXISTENCE OF LARGE DEGREE GALOIS REPRESENTATIONS FOR FIELDS OF SMALL DISCRIMINANT

Let L=K be a Galois extension of number fields. We prove two lower bounds on the maximum of the degrees of the irreducible complex representations of Gal.L=K/, the sharper of which is conditional on the Artin conjecture and the generalized Riemann hypothesis. Our bound is nontrivial when TK V QU is small and L has small root discriminant, and might be summarized as saying that such fields can’t be “too abelian”.
The Recent Evolution of Early-Type Galaxies as Seen in their Cold Gas

I present an overview of new observations of atomic and molecular gas in early-type galaxies, focusing on the Atlas project. Our data on stellar kinematics, age and metallicity, and ionized gas kinematics allow us to place the cold gas into the broader context of early-type galaxy assembly and star formation history. The cold gas data also provide valuable constraints for numerical simulations of early-type galaxies.
AlGaN channel field effect transistors with graded heterostructure ohmic contacts

We report on ultra-wide bandgap (UWBG) Al0.75Ga0.25N channel metal-insulator-semiconductor field-effect transistors (MISFETs) with heterostructure engineered low-resistance ohmic contacts. The low intrinsic electron affinity of AlN (0.6 eV) leads to large Schottky barriers at the metal-AlGaN interface, resulting in highly resistive ohmic contacts. In this work, we use a reverse compositional graded n++ AlGaN contact layer to achieve upward electron affinity grading, leading to a low specific contact resistance (ρsp) of 1.9 × 10−6 Ω cm2 to n-Al0.75Ga0.25N channels (bandgap ∼5.3 eV) with non-alloyed contacts. We also demonstrate UWBG Al0.75Ga0.25N channel MISFET device operation employing the compositional graded n++ ohmic contact layer and 20 nm atomic layer deposited Al2O3 as the gate-dielectric.
Dual Role of Cell-Cell Adhesion In Tumor Suppression and Proliferation Due to Collective Mechanosensing

It is known that mechanical interactions couple a cell to its neighbors, enabling a feedback loop to regulate tissue growth. However, the interplay between cell-cell adhesion strength, local cell density and force fluctuations in regulating cell proliferation is poorly understood. Here, we show that spatial variations in the tumor growth rates, which depend on the location of cells within tissue spheroids, are strongly influenced by cell-cell adhesion. As the strength of the cell-cell adhesion increases, intercellular pressure initially decreases, enabling dormant cells to more readily enter into a proliferative state. We identify an optimal cell-cell adhesion regime where pressure on a cell is a minimum, allowing for maximum proliferation. We use a theoretical model to validate this novel collective feedback mechanism coupling adhesion strength, local stress fluctuations and proliferation. Our results, predicting the existence of a non-monotonic proliferation behavior as a function of adhesion strength, are consistent with experimental results. Several experimental implications of the proposed role of cell-cell adhesion in proliferation are quantified, making our model predictions amenable to further experimental scrutiny. We show that the mechanism of contact inhibition of proliferation, based on a pressure-adhesion feedback loop, serves as a unifying mechanism to understand the role of cell-cell adhesion in proliferation.
Classical Simulation of Yang-Baxter Gates.

A unitary operator that satisfies the constant Yang-Baxter equation immediately yields a unitary representation of the braid group B_n for every n >= 2. If we view such an operator as a quantum-computational gate, then topological braiding corresponds to a quantum circuit. A basic question is when such a representation affords universal quantum computation. In this work, we show how to classically simulate these circuits when the gate in question belongs to certain families of solutions to the Yang-Baxter equation. These include all of the qubit (i.e., d = 2) solutions, and some simple families that include solutions for arbitrary d >= 2. Our main tool is a probabilistic classical algorithm for efficient simulation of a more general class of quantum circuits. This algorithm may be of use outside the present setting.
Scenario planning and nanotechnological futures

Scenario planning may assist us in harnessing the benefits of nanotechnology and managing the associated risks for the good of the society. Scenario planning is a way to describe the present state of the world and develop several hypotheses about the future of the world, thereby enabling discussions about how the world ought to be. Scenario planning thus is not only a tool for learning and foresight, but also for leadership. Informed decision making by experts and political leaders becomes possible, while simultaneously allaying the public's perception of the risks of new and emerging technologies such as nanotechnology. Two scenarios of the societal impact of nanotechnology are the mixed-signals scenario and the confluence scenario. Technoscientists have major roles to play in both scenarios.
A three-dimensional constitutive model for the martensitic transformation in polycrystalline shape memory alloys under large deformation

This work presents a three-dimensional constitutive model for the martensitic transformation in polycrystalline Shape Memory Alloys (SMAs) under large deformation. By utilizing the logarithmic strain and rate, the model is able to account for large strains and rotations that SMA-based components may undertake, but also resolves the artificial stress errors caused by the non-integrable objective rates that are widely used in current commercial finite element software. The model is developed through classical thermodynamic laws combined with the standard Coleman-Noll procedure. The scalar martensitic volume fraction and the second-order transformation strain tensor are chosen as the internal state variables to capture the material response exhibited by polycrystalline SMAs. A detailed implementation procedure of the proposed model is described through a user-defined material subroutine. Numerical experiments considering SMA components including a bar, a beam, a torque tube and a solid flexible structure under stress/thermally-induced phase transformations are investigated via the proposed model, and the results under cyclic loading are compared against the predictions provided by the Abaqus nonlinear solver. The development framework of the proposed model and its implementation procedure can be extended to incorporate other nonlinear phenomena exhibited by SMAs, such as transformation-induced plasticity, viscoplasticity, and damage under large deformation.
An Incentive-Based Online Optimization Framework for Distribution Grids

This paper formulates a time-varying social-welfare maximization problem for distribution grids with distributed energy resources (DERs) and develops online distributed algorithms to identify (and track) its solutions. In the considered setting, network operator and DER-owners pursue given operational and economic objectives, while concurrently ensuring that voltages are within prescribed limits. The proposed algorithm affords an online implementation to enable tracking of the solutions in the presence of time-varying operational conditions and changing optimization objectives. It involves a strategy where the network operator collects voltage measurements throughout the feeder to build incentive signals for the DER-owners in real time; DERs then adjust the generated/consumed powers in order to avoid the violation of the voltage constraints while maximizing given objectives. The stability of the proposed schemes is analytically established and numerically corroborated.
Decoupled sectors and Wolf–Rayet galaxies

It has recently been proposed that gamma-ray burst (GRB) events may be modified by the presence of a dark matter sector subcomponent that is charged under an unbroken U(1). This proposal depends upon there being a nontrivial density of charged dark matter in star forming regions of galaxies which host GRBs. We discuss four Wolf–Rayet galaxies (NGC 1614, NGC 3367, NGC 4216 and NGC 5430) which should contain comparable amounts of dark matter gas and visible matter gas in the star forming regions. We show that the ratio of dark jet power to visible jet power depends only on the ratio of particle mass and charge when the densities are equal, allowing for these input parameters to be probed directly by future observations of GRBs.
SPIN-DOWN MEASUREMENT OF PSR J1813–1749: THE ENERGETIC PULSAR POWERING HESS J1813–178

Two new X-ray timing observations of the 44.7 ms pulsar in G12.82-0.02/HESS J1813-178 were obtained with Chandra and XMM-Newton to determine its precise spin-down rate. With a period derivative of P-dot 1.265 Multiplication-Sign 10{sup -13}, PSR J1813-1749 is the third most energetic pulsar in the Galaxy, having spin-down luminosity E-dot 5.6 Multiplication-Sign 10{sup 37} erg s{sup -1}. Lack of pulsed detection in a deep radio search from the Green Bank Telescope, and in {gamma}-rays from Fermi, are reported. We reconsider the distance to PSR J1813-1749/G12.82-0.02 in view of its large X-ray measured column density, N{sub H} = 10 Multiplication-Sign 10{sup 22} cm{sup -2}, which exceeds the visual extinction A{sub V} = 9.1 to a young stellar cluster at d = 4.8 kpc that has been associated with it. Although the distance may well be larger, existing data do not constrain it further. The small radiative output of PSR J1813-1749/G12.82-0.02 in all bands would not exceed its spin-down power at any distance in the Galactic disk.
Superfluidity of Flexible Chains of Polar Molecules

We study quantum chains formed in a gas of polar bosonic molecules confined in a stack of N identical one- and two-dimensional optical lattice layers, with molecular dipole moments aligned perpendicularly to the layers. Quantum Monte Carlo simulations of a single chain reveal its quantum roughening transition. The case of finite in-layer density of molecules is analyzed within the J-current model approximation, and it is found that N-layered molecular superfluid phase can undergo a quantum phase transition to a rough chain superfluid. A theorem is proven that no superfluidity of chains with length shorter than N is possible. The scheme for detecting the chain formation is proposed.
Predicting Online Extremism, Content Adopters, and Interaction Reciprocity

We present a machine learning framework that leverages a mixture of metadata, network, and temporal features to detect extremist users, and predict content adopters and interaction reciprocity in social media. We exploit a unique dataset containing millions of tweets generated by more than 25 thousand users who have been manually identified, reported, and suspended by Twitter due to their involvement with extremist campaigns. We also leverage millions of tweets generated by a random sample of 25 thousand regular users who were exposed to, or consumed, extremist content. We carry out three forecasting tasks, (i) to detect extremist users, (ii) to estimate whether regular users will adopt extremist content, and finally (iii) to predict whether users will reciprocate contacts initiated by extremists. All forecasting tasks are set up in two scenarios: a post hoc (time independent) prediction task on aggregated data, and a simulated real-time prediction task. The performance of our framework is extremely promising, yielding in the different forecasting scenarios up to 93 % AUC for extremist user detection, up to 80 % AUC for content adoption prediction, and finally up to 72 % AUC for interaction reciprocity forecasting. We conclude by providing a thorough feature analysis that helps determine which are the emerging signals that provide predictive power in different scenarios.
Enabling Cooperative IoT Security via Software Defined Networks (SDN)

Internet of Things (IoT) is becoming an increasingly attractive target for cybercriminals. We observe that many attacks to IoTs are launched in a collusive way, such as brute-force hacking usernames and passwords, to target at a particular victim. However, most of the time our defending mechanisms to such kind of attacks are carried out individually and independently, which leads to ineffective and weak defense. To this end, we propose to leverage Software Defined Networks (SDN) to enable cooperative security for legacy IP-based IoT devices. SDN decouples control plane and data plane, and can help bridge the knowledge divided between the application and network layers. In this paper, we discuss the IoT security problems and challenges, and present an SDN-based architecture to enable IoT security in a cooperative manner. Furthermore, we implemented a platform that can quickly share the attacking information with peer controllers and block the attacks. We carried out our experiments in both virtual and physical SDN environments with OpenFlow switches. Our evaluation results show that both environments can scale well to handle attacks, but hardware implementation is much more efficient than a virtual one.
The Extended Bogomolny Equations and Generalized Nahm Pole Boundary Condition

We develop a Kobayashi–Hitchin-type correspondence between solutions of the extended Bogomolny equations on Σ×ℝ+ with Nahm pole singularity at Σ×{0} and the Hitchin component of the stable SL(2,ℝ) Higgs bundle; this verifies a conjecture of Gaiotto and Witten. We also develop a partial Kobayashi–Hitchin correspondence for solutions with a knot singularity in this program, corresponding to the non-Hitchin components in the moduli space of stable SL(2,ℝ) Higgs bundles. We also prove existence and uniqueness of solutions with knot singularities on ℂ×ℝ+.
A model for the analysis of security policies in service function chains

Two emerging architectural paradigms, i.e., Software Defined Networking (SDN) and Network Function Virtualization (NFV), enable the deployment and management of Service Function Chains (SFCs). A SFC is an ordered sequence of abstract Service Functions (SFs), e.g., firewalls, VPN-gateways, traffic monitors, that packets have to traverse in the route from source to destination. While this appealing solution offers significant advantages in terms of flexibility, it also introduces new challenges such as the correct configuration and ordering of SFs in the chain to satisfy overall security requirements. This paper presents a formal model conceived to enable the verification of correct policy enforcements in SFCs. Software tools based on the model can then be designed to cope with unwanted network behaviors (e.g., security flaws) deriving from incorrect interactions of SFs in the same SFC.
Squeezed vacuum used to accelerate the search for a weak classical signal

Many experiments that interrogate fundamental theories require detectors whose sensitivities are limited by the laws of quantum mechanics. In cavity-based searches for axionic dark matter, vacuum fluctuations in the two quadratures of the cavity electromagnetic field limit the sensitivity to an axion-induced field. In an apparatus designed to partially mimic existing axion detectors, we demonstrate experimentally that such quantum limits can be overcome through the use of squeezed states. By preparing a microwave cavity in a squeezed state and measuring just the squeezed quadrature, we enhance the spectral scan rate by a factor of 2.12±0.08. This enhancement is in excellent quantitative agreement with a theoretical model accounting for both imperfect squeezing and measurement.
Gravitational focusing and substructure effects on the rate modulation in direct dark matter searches

We study how gravitational focusing (GF) of dark matter by the Sun affects the annual and biannual modulation of the expected signal in non-directional direct dark matter searches, in the presence of dark matter substructure in the local dark halo. We consider the Sagittarius stream and a possible dark disk, and show that GF suppresses some, but not all, of the distinguishing features that would characterize substructure of the dark halo were GF neglected.
The effect of bound states on X-ray Thomson scattering for partially ionized plasmas

Abstract X-ray Thomson scattering is being developed as a method to measure the temperature, electron density, and ionization state of high energy density plasmas such as those used in inertial confinement fusion. X-ray laser sources have always been of interest because of the need to have a bright monochromatic X-ray source to overcome plasma emission and eliminate other lines in the background that complicate the analysis. With the advent of the X-ray free electron laser (X-FEL) at the SNAL Linac Coherent Light Source (LCLS) and other facilities coming online worldwide, we now have such a source available in the keV regime. An important challenge with X-ray Thomson scattering experiments is understanding how to model the scattering for partially ionized plasmas. Most Thomson scattering codes used to model experimental data greatly simplify or neglect the contributions of the bound electrons to the scattered intensity. In this work we take the existing models of Thomson scattering that include elastic ion–ion scattering and inelastic electron–electron scattering and add the contribution of bound electrons in the partially ionized plasmas. Except for hydrogen plasmas, most plasmas studied today have bound electrons and it is important to understand their contribution to the Thomson scattering, especially as new X-ray sources such as an X-FEL will allow us to study much higher Z plasmas. To date, most experiments have studied hydrogen or beryllium plasmas. We first analyze existing experimental data for beryllium to validate the code. We then consider several higher Z materials such as Cr and predict the existence of additional peaks in the scattering spectrum that require new computational tools to understand. For a Sn plasma, we show that bound contributions change the shape of the scattered spectrum in a way that would change the plasma temperature and density inferred from experiment.
Convolution Inequalities for the Boltzmann Collision Operator

We study integrability properties of a general version of the Boltzmann collision operator for hard and soft potentials in n-dimensions. A reformulation of the collisional integrals allows us to write the weak form of the collision operator as a weighted convolution, where the weight is given by an operator invariant under rotations. Using a symmetrization technique in Lp we prove a Young’s inequality for hard potentials, which is sharp for Maxwell molecules in the L2 case. Further, we find a new Hardy-Littlewood-Sobolev type of inequality for Boltzmann collision integrals with soft potentials. The same method extends to radially symmetric, non-increasing potentials that lie in some \({L^{s}_{weak}}\) or Ls. The method we use resembles a Brascamp, Lieb and Luttinger approach for multilinear weighted convolution inequalities and follows a weak formulation setting. Consequently, it is closely connected to the classical analysis of Young and Hardy-Littlewood-Sobolev inequalities. In all cases, the inequality constants are explicitly given by formulas depending on integrability conditions of the angular cross section (in the spirit of Grad cut-off). As an additional application of the technique we also obtain estimates with exponential weights for hard potentials in both conservative and dissipative interactions.
SQUARE: strategic quantum ancilla reuse for modular quantum programs via cost-effective uncomputation

Compiling high-level quantum programs to machines that are size constrained (i.e. limited number of quantum bits) and time constrained (i.e. limited number of quantum operations) is challenging. In this paper, we present SQUARE (Strategic QUantum Ancilla REuse), a compilation infrastructure that tackles allocation and reclamation of scratch qubits (called ancilla) in modular quantum programs. At its core, SQUARE strategically performs uncomputation to create opportunities for qubit reuse.Current Noisy Intermediate-Scale Quantum (NISQ) computers and forward-looking Fault-Tolerant (FT) quantum computers have fundamentally different constraints such as data locality, instruction parallelism, and communication overhead. Our heuristic-based ancilla-reuse algorithm balances these considerations and fits computations into resource-constrained NISQ or FT quantum machines, throttling parallelism when necessary. To precisely capture the workload of a program, we propose an improved metric, the “active quantum volume,” and use this metric to evaluate the effectiveness of our algorithm. Our results show that SQUARE improves the average success rate of NISQ applications by 1. 47X. Surprisingly, the additional gates for uncomputation create ancilla with better locality, and result in substantially fewer swap gates and less gate noise overall. SQUARE also achieves an average reduction of 1. 5X (and up to 9. 6X) in active quantum volume for FT machines.
Cable Capacitance Attack Against the KLJN Secure Key Exchange

The security of the Kirchhoff-law-Johnson-(like)-noise (KLJN) key exchange system is based on the fluctuation-dissipation theorem of classical statistical physics. Similarly to quantum key distribution, in practical situations, due to the non-idealities of the building elements, there is a small information leak, which can be mitigated by privacy amplification or other techniques so that unconditional (information-theoretic) security is preserved. In this paper, the industrial cable and circuit simulator LTSPICE is used to validate the information leak due to one of the non-idealities in KLJN, the parasitic (cable) capacitance. Simulation results show that privacy amplification and/or capacitor killer (capacitance compensation) arrangements can effectively eliminate the leak.
Mass Gap in Weakly Coupled Abelian Higgs on a Unit Lattice

The proof of the Higgs mechanism in a weakly coupled lattice gauge theory in $$d \geqslant 2$$ is revisited. A new power series cluster expansion is applied, and the mass gap is shown to exist for the observable $$F_{\mu \nu }$$ .
Entanglement entropy, dualities, and deconfinement in gauge theories

Computing the entanglement entropy in confining gauge theories is often accompanied by puzzles and ambiguities. In this work we show that compactifying the theory on a small circle $$ {\mathbb{S}}_L^1 $$ evades these difficulties. In particular, we study Yang-Mills theory on $$ {\mathrm{\mathbb{R}}}^3\times {\mathbb{S}}_L^1 $$ with double-trace deformations or adjoint fermions and hold it at temperatures near the deconfinement transition. This theory is dual to a multi-component (electric-magnetic) Coulomb gas that can be mapped either to an XY-spin model with ℤp symmetry-preserving perturbations or dual Sine-Gordon model. The entanglement entropy of the dual Sine-Gordon model exhibits an extremum at the critical temperature/crossover. We also compute Renyi mutual information (RMI) of the XY-spin model by means of the replica trick and Monte Carlo simulations. These are expensive calculations, since one in general needs to suppress lower winding vortices that do not correspond to physical excitations of the system. We use a T-duality that maps the original XY model to its mirror image, making the extraction of RMI a much efficient process. Our simulations indicate that RMI follows the area law scaling, with subleading corrections, and this quantity can be used as a genuine probe to detect deconfinement transitions. We also discuss the effect of fundamental matter on RMI and the implications of our findings in gauge theories and beyond.
Matrix theory and U-duality in seven dimensions

Abstract We demonstrate the emergence of the U-duality group in compactification of Matrix theory on a 4-torus. The discussion involves non-trivial effects in strongly coupled 4+1 dimensional gauge theory, and highlights some interesting phenomena in the Matrix theory description of compactified M-theory.
A Markov Chain Algorithm for Compression in Self-Organizing Particle Systems

We consider programmable matter as a collection of simple computational elements (or particles) with limited (constant-size) memory that self-organize to solve system-wide problems of movement, configuration, and coordination. Here, we focus on the compression problem, in which the particle system gathers as tightly together as possible, as in a sphere or its equivalent in the presence of some underlying geometry. More specifically, we seek fully distributed, local, and asynchronous algorithms that lead the system to converge to a configuration with small perimeter. We present a Markov chain based algorithm that solves the compression problem under the geometric amoebot model, for particle systems that begin in a connected configuration with no holes. The algorithm takes as input a bias parameter λ, where λ > 1 corresponds to particles favoring inducing more lattice triangles within the particle system. We show that for all λ > 5, there is a constant α > 1 such that at stationarity with all but exponentially small probability the particles are α-compressed, meaning the perimeter of the system configuration is at most α ⋅ pmin, where pmin is the minimum possible perimeter of the particle system. We additionally prove that the same algorithm can be used for expansion for small values of λ in particular, for all 0
Language Technology Resource Center.

This paper describes the Language Technology Resource Center (LTRC), a United States Government website for providing information and tools for users of languages (e.g., translators, analysts, systems administrators, researchers, developers, etc.) The LTRC provides information on a broad range of products and tools. It also provides a survey where product developers and researchers can provide the U.S. Government and the public with information about their work. A variety of reports are generated, including reports of all tools of a given type in a given language or dialect. Information is provided about standards, professional organizations, online resources, and other resources. The LTRC was developed and is run by MITRE, a Federally Funded Research and Development Center (FFRDC), on behalf of the U.S. Government. One of the major challenges for the future is to identify and provide information on the many new tools that are appearing. International collaboration is critical to cover this number of tools.
Structural basis for the association of PLEKHA7 with membrane-embedded phosphatidylinositol lipids

Summary PLEKHA7 (pleckstrin homology domain containing family A member 7) plays key roles in intracellular signaling, cytoskeletal organization, and cell adhesion, and is associated with multiple human cancers. The interactions of its pleckstrin homology (PH) domain with membrane phosphatidyl-inositol-phosphate (PIP) lipids are critical for proper cellular localization and function, but little is known about how PLEKHA7 and other PH domains interact with membrane-embedded PIPs. Here we describe the structural basis for recognition of membrane-bound PIPs by PLEHA7. Using X-ray crystallography, nuclear magnetic resonance, molecular dynamics simulations, and isothermal titration calorimetry, we show that the interaction of PLEKHA7 with PIPs is multivalent, distinct from a discrete one-to-one interaction, and induces PIP clustering. Our findings reveal a central role of the membrane assembly in mediating protein-PIP association and provide a roadmap for understanding how the PH domain contributes to the signaling, adhesion, and nanoclustering functions of PLEKHA7.
Linear Degrees of Freedom of the MIMO X-Channel With Delayed CSIT

We study the degrees of freedom (DoFs) of the multiple-input multiple-output X-channel (MIMO XC) with delayed channel state information at the transmitters (delayed CSITs), assuming linear coding strategies at the transmitters. We present two results: 1) the linear sum DoF for MIMO XC with general antenna configurations and 2) the linear DoF region for MIMO XC with symmetric antennas. The converse for each result is based on developing a novel rank-ratio inequality that characterizes the maximum ratio between the dimensions of received linear subspaces at the two multiple-antenna receivers. The achievability of the linear sum DoF is based on a three-phase strategy, in which during the first two phases only the transmitter with fewer antennas exploits delayed CSIT in order to minimize the dimension of its signal at the unintended receiver. During the third phase, both transmitters use delayed CSIT to send linear combinations of past transmissions, such that each receiver receives a superposition of desired message data and known interference, thus simultaneously serving both receivers. We also derive other linear DoF outer bounds for the MIMO XC that, in addition to the outer bounds from the sum DoF converse and the proposed transmission strategy, allow us to characterize the linear DoF region for symmetric antenna configurations.
Structure of quantum entanglement at a finite temperature critical point

The authors propose a scheme to characterize quantum entanglement close to a finite temperature critical point using an entanglement measure for mixed states. They show that despite a diverging correlation length at the critical point, the entanglement is only short-ranged.
Perfect Storm: Climate Change and Tourism

While the world’s attention is on dealing with the COVID-19 pandemic, climate change remains a greater existential threat to vulnerable countries that are highly dependent on a weather-sensitive sector like tourism. Using a novel multidimensional index, this study investigates the long-term impact of climate change vulnerability on international tourism in a panel of 15 Caribbean countries over the period 1995–2017. Empirical results show that climate vulnerability already has a statistically and economically significant negative effect on international tourism revenues across the region. As extreme weather events are becoming more frequent and severe over time, our findings indicate that the Caribbean countries need to pursue comprehensive adaptation policies to reduce vulnerabilities to climate change.
A rate threshold mechanism regulates MAPK stress signaling and survival

Cells are exposed to changes in extracellular stimulus concentration that vary as a function of rate. However, how cells integrate information conveyed from stimulation rate along with concentration remains poorly understood. Here, we examined how varying the rate of stress application alters budding yeast mitogen-activated protein kinase (MAPK) signaling and cell behavior at the single-cell level. We show that signaling depends on a rate threshold that operates in conjunction with stimulus concentration to determine the timing of MAPK signaling during rate-varying stimulus treatments. We also discovered that the stimulation rate threshold and stimulation rate-dependent cell survival are sensitive to changes in the expression levels of the Ptp2 phosphatase, but not of another phosphatase that similarly regulates osmostress signaling during switch-like treatments. Our results demonstrate that stimulation rate is a regulated determinant of cell behavior and provide a paradigm to guide the dissection of major stimulation rate dependent mechanisms in other systems.
Mechanical Tuning of the Terahertz Photonic Bandgap of 3D-Printed One-Dimensional Photonic Crystals

Mechanical tuning of a 3D-printed, polymer-based one-dimensional photonic crystal was demonstrated in the terahertz spectral range. The investigated photonic crystal consists of 13 alternating compact and low-density layers and was fabricated through single-step stereolithography. While the compact layers are entirely polymethacrylate without any intentional internal structures, the low-density layers contain sub-wavelength sized slanted columnar inclusions to allow the mechanical compression in a direction normal to the layer interfaces of the photonic crystal. Terahertz transmission spectroscopy of the photonic crystal was performed in a spectral range from 83 to 124 GHz as a function of the compressive strain. The as-fabricated photonic crystal showed a distinct photonic bandgap centered at 109 GHz, which blue shifted under compressive stress. A maximum shift of 12 GHz in the bandgap center frequency was experimentally demonstrated. Stratified optical models incorporating simple homogeneous and inhomogeneous compression approximations were used to analyze the transmission data. A good agreement between the experimental and model-calculated transmission spectra was found.
Investor Flows and Stock Market Returns

This study simultaneously analyzes the relation between aggregate stock market returns and cash flows (net purchases of equity) from a broad array of investor groups in the United States over a long period of time from 1952 to 2004. We find strong evidence that quarterly flows are autocorrelated for each of the different investor groups. We further document a significant and positive contemporaneous relation between stock market returns and flows of Mutual Funds and Foreign Investors.
Do Capital Structure Adjustments by Takeover Targets Influence Acquisition Gains

Existing theoretical models predict that takeover targets optimally increase debt and repurchase equity around takeover attempts. Ultimately, these leverage shifts should benefit target shareholders and enhance bargaining power in negotiations with acquiring firms. We show that target firms indeed issue higher levels of debt, and simultaneously repurchase more equity, relative to a set of matched firms, during the period from one year prior to takeover announcement through completion. We find that bank debt is the primary source of these debt increases. Lastly, we find evidence consistent with the expectation of improved bargaining power for target equityholders with target debt issuances. We document that compared to debt issued by non-target firms, announcements of debt issuances by takeover targets are associated with additional positive abnormal returns to target stockholders. Additionally, at least some of these target equity gains appear to come at the expense of bidder shareholders. These impacts on target and bidder abnormal returns are more significant for debt issuances occurring in the periods immediately preceding and following takeover announcement, as well as for issuances of bank debt. Debt issuances occurring after takeover announcement appear to reverse initially lower (higher) abnormal returns experienced by targets (bidders) upon takeover announcement itself, and further increase the likelihood of positive adjustments to acquisition premiums offered by the bidders to the targets.
Greatness Thrust upon Them: Class Biases in American Law

A common view of our present society is that it is largely egalitarian and classless. This paper proposes that this conception of an egalitarian and classless society belies reality. It argues that there is a dominant class of leaders in government, labor, and business who are characterized by their organizational skills and their technical expertise, and who have more in common with one another that they have with the respective constituencies in whose name they exercise power. It further argues that this class, in effect, is able to wield power to control the structure of society and the legal system to closely match their experiences and concerns without adequate regard for those more vulnerable than themselves. It concludes, after many examples of class biases in the law, by reflecting on how protection of the rest of society through legal reform is a positive moral duty which all of those in the controlling class must embrace.
Anti‐dumping Reform: Time to Go Back to Basics

This paper traces and analyses both the legal and economic history of the US anti-dumping regime, and sets forth the shortcomings of the current system, both in regards to efficiency and equity. It then presents and explains a series of proposals for reform of the system, ranging from abolition of anti-dumping laws and regulations and their replacement with competition laws, down to less drastic but specific changes within the existing system to render it less onerous to consumers and exporters. The paper finally details the case for substituting safeguards actions for anti-dumping actions.
Fear, Social Projection, and Financial Decision Making

Abstract The number of individual investors who trade stocks online has significantly increased in recent years. Surprisingly, consumer researchers have paid little attention to how emotions influence individual investors' stock-trading decisions. In a series of three experiments, the authors investigate the impact of incidental fear on the decision to sell in a stock market simulation. The results show that fearful (vs. control) participants sell their stock earlier (Experiments 1–3). This effect, however, is contingent on particular features of the market. Fear leads to early sell-off when partipant believe the value of the stock is peer generated but not when they believe the value of the stock is computer generated (Experiment 2). Early sell-off as a result of incidental fear also occurs when participants believe their risk attitude is common in the market but not when they believe their risk attitude is unique (Experiment 3). Social projection—that is, people's tendency to rely on their current state...
Only Fools Who Send Hyenas to Roast Meat for Them: In Search of the Doctrinal Foundations of the Not-So-Ordinary Crime of Patrimonicide

Crimes against humanity are generally considered crimes of such unimaginable horror that they shock the conscience of mankind. The Article challenges the international community to take a mental leap by recognizing that the contemporary version of official corruption is so fundamentally different from its historical antecedents that it deserves to (a) be called a different name: indigenous spoliation or patrimonicide; and (b), to be treated as an extraordinary crime that rises up to the level of a crime against humanity. Towards this end, the Article reviews the basic elements of a crime against humanity identified in various legal instruments, and in the law and practice of the three United Nations' ad hoc criminal tribunals. On the basis of this analysis, the Article then proceeds to demonstrate the link between the * PhD, JD (Northwestern); University Distinguished Professor & Professor of Law, Dedman School of Law, Southern Methodist University, (SMU), Dallas, Texas USA. Email Address: nkofele@smu.edu. An earlier and abbreviated version of this paper was presented as the keynote address under the title "SED QUIS CUSTODIET IPSOS CUSTODIES?" (BUT WHO WILL GUARD the GUARDIANS?) The Case for Elevating Official Corruption to the Status of a Crime in Positive International Law," at the 22nd Annual Fulbright Symposium on International Legal Problems, Golden Gate University School of Law, San Francisco, California, April 6, 2012. I would like to thank President Dan Angel of Golden Gate University, Dean Drucilla Ramey and the Faculty of the Law School, and Associate Dean Jon Sylvester and the members of the Graduate Law Programs, for hosting this symposium to honor the memory of a great American and world statesman, the late Senator William J. Fulbright. I also extend warm and fraternal greetings to Professor Christian Nwachukwu Okeke who made my participation at this very important gathering of international law scholars from around the globe possible. Professor Okeke has for three decades provided inspiring leadership in legal education here in the United States and in Nigeria. He has also contributed immensely to the progressive development and advancement of international law. I salute him! This Article was supported by a summer research grant from the SMU Dedman School of Law. Julienne Gilmore, JD (2012), SMU Dedman School of Law, Brenda Cordoner, JD (2013) SMU Dedman School of Law, and Elizabeth Rukundo, LL.B. (Makerere), LL.M.( 2013), SMU Dedman School of Law, provided valuable research assistance to this article, for which the author is grateful.
The Application of the Religious Freedom Restoration Act to Appearance Regulations That Presumptively Prohibit Observant Sikh Lawyers From Joining the U.S. Army Judge Advocate General Corps

Observant Sikh lawyers are presumptively prohibited from joining the U.S. Army Judge Advocate General (JAG) Corps because they cannot satisfy the Army’s appearance regulations. This essay argues that this presumptive prohibition violates the Religious Freedom Restoration Act (RFRA). Under RFRA, the federal government may substantially burden an individual’s exercise of religion only if it demonstrates that its application of the burden furthers a compelling governmental interest by the least restrictive means.1 The Army’s appearance regulations are designed to promote two interests—uniformity and safety. In the course of furthering these interests, the Army’s appearance regulations effectively preclude observant Sikhs from joining the U.S. Army JAG Corps. The Sikh religion requires its male followers to wear turbans and forbids all of its followers from cutting their hair. Both requirements purportedly interfere with the Army’s asserted interests in uniformity and safety. This purported interference forms the basis for a conclusion that observant Sikhs are appropriately excluded from joining the U.S. Army JAG Corps. This essay argues against the necessity of such a conclusion by demonstrating that under RFRA (1) the Army does not have a compelling interest in disallowing exceptions to its appearance regulations, and (2) the Army’s appearance regulations do not constitute the least restrictive means of promoting safety. Because the Army’s appearance regulations violate RFRA, they must be amended to allow for the accommodation of observant Sikhs in the U.S. Army JAG Corps.
The Effects of Regulating Hidden Add-On Costs

We examine the welfare effects of price and disclosure regulation in a model where firms can shroud add-on costs, such as penalty fees for consumer financial products. Such regulation can increase or decrease welfare even when there are no direct costs. There are, however, strong complementarities between price controls and disclosure mandates: conditional on disclosure being mandated, price controls always (weakly) increase welfare, and conditional on prices being sufficiently constrained, disclosure mandates always (weakly) increase welfare.
Debt Covenant Violations, Firm Financial Distress, and Auditor Actions

We conduct a comprehensive study on the associations between debt covenant violations (“violations”) and auditor actions for financially distressed and nondistressed firms. Our study is motivated by a lack of research on the consequences of violations resulting from auditors' actions. We find that firms with violations have significantly higher audit fees, a greater likelihood of receiving a going-concern opinion, and a greater likelihood of experiencing an auditor resignation. Importantly, the positive associations hold for all types of firms, including financially nondistressed firms. In fact, we find that, after controlling for other financial information, the relation between violations and an increased likelihood of a going-concern opinion is stronger for nondistressed versus distressed firms. Our evidence is consistent with belief-revision research in auditing that finds auditors react more strongly to information that is inconsistent with their prior beliefs. This study provides further evidence on the indirect yet significant consequences of covenant violations on firms resulting from auditor actions.
Medical Decision Making by and on Behalf of Adolescents: Reconsidering First Principles

The school nurse cannot give your teenage daughter an aspirin for her headache without your permission, but that same daughter can get an abortion without even informing you. Or can she? The obligations on medical personnel providing care to adolescents are famously indeterminate.Two common-law presumptions have long lurked in the background, but, far from elucidating matters, those presumptions have contributed to the state of confusion. The first presumption is that, absent any special rule, children lack the legal authority to consent to medical treatment on their own. A parallel and corresponding presumption is that parents have a legal entitlement to make medical decisions for their minor children.This article questions whether those propositions have any force today — if, in fact, they ever did. Both as a descriptive matter and as a constitutional matter, these statements are highly questionable, particularly when adolescents are involved.This article therefore makes the case that neither presumed truth about the American legal landscape is valid, at least with respect to older minors. It also suggests that the ultimate failure of the law to provide solid and meaningful background presumptions in the domain of minors’ medical decision-making rights has done much to aggravate, if not create, the muddle of regulation that confounds health care providers.The constitutional doctrine pertaining to minors’ rights to bodily integrity, moreover, both highlights and founders upon the extreme lack of clarity with respect to the relevant default rules regarding older minors’ ability to consent to medical care. Increased judicial attention directed toward developing the constitutional doctrine surrounding minors‘ rights to bodily integrity would therefore be beneficial both to health care providers and to minors.
Urbanization, agglomeration economies, and access to mortgage credit

Abstract We examine the effect of urban agglomeration on access to mortgage credit using HMDA data from 1994 to 2008. Previous studies suggest that agglomeration should increase access to specialized workers and information, both of which should enhance liquidity in mortgage lending. Findings indicate that agglomeration economies increase mortgage origination rates and loan amounts in the 1990s, and especially so in higher risk locations. However, agglomeration effects dissipated over the study period. While we do not identify the microfoundations of these patterns, the decline in the influence of agglomeration coincides with the dramatic expansion of secondary mortgage markets and development of information technology, both of which should have reduced regional disparities in access to credit.
College enrollment over the business cycle: the role of supply constraints

Studies on the cyclicality of higher education examine the relationship between variations in labor market conditions and changes in enrollment. While the majority of the existing literature implic...