cssi/SciSciGPT-SciSciNet huggingface dataset:
A joint analysis of Planck and BICEP2 B modes including dust polarization uncertainty

We analyze BICEP2 and Planck data using a model that includes CMB lensing, gravity waves, and polarized dust. Recently published Planck dust polarization maps have highlighted the difficulty of estimating the amount of dust polarization in low intensity regions, suggesting that the polarization fractions have considerable uncertainties and may be significantly higher than previous predictions. In this paper, we start by assuming nothing about the dust polarization except for the power spectrum shape, which we take to be C{sub l}{sup BB,dust} ∝ l{sup -2.42}. The resulting joint BICEP2+Planck analysis favors solutions without gravity waves, and the upper limit on the tensor-to-scalar ratio is r 0.14 are excluded with 99.5% confidence). We address the cross-correlation analysis of BICEP2 at 150 GHz with BICEP1 at 100 GHz as a testmore » of foreground contamination. We find that the null hypothesis of dust and lensing with 0r= gives Δ χ{sup 2} < 2 relative to the hypothesis of no dust, so the frequency analysis does not strongly favor either model over the other. We also discuss how more accurate dust polarization maps may improve our constraints. If the dust polarization is measured perfectly, the limit can reach r < 0.05 (or the corresponding detection significance if the observed dust signal plus the expected lensing signal is below the BICEP2 observations), but this degrades quickly to almost no improvement if the dust calibration error is 20% or larger or if the dust maps are not processed through the BICEP2 pipeline, inducing sampling variance noise.« less
The homotopy invariance of the string topology loop product and string bracket

Let M n be a closed, oriented, n-manifold, and LM its free loop space. In [4] a commutative algebra structure in homology, H�(LM), and a Lie algebra structure in equivariant homology H S 1 � (LM), were defined. In this paper we prove that these structures are homotopy invariants in the following sense. Let f : M1 ! M2 be a homotopy equivalence of closed, oriented n-manifolds. Then the induced equivalence, Lf : LM1 ! LM2 induces a ring isomorphism in homology, and an isomorphism of Lie algebras in equivariant homology. The analogous statement also holds
Canonical bases and higher representation theory

This paper develops a general theory of canonical bases and how they arise naturally in the context of categorification. As an application, we show that Lusztig’s canonical basis in the whole quantized universal enveloping algebra is given by the classes of the indecomposable 1-morphisms in a categorification when the associated Lie algebra is of finite type and simply laced. We also introduce natural categories whose Grothendieck groups correspond to the tensor products of lowest- and highest-weight integrable representations. This generalizes past work of the author’s in the highest-weight case.
Congested aggregation via Newtonian interaction

We consider a congested aggregation model that describes the evolution of a density through the competing effects of nonlocal Newtonian attraction and a hard height constraint. This provides a counterpoint to existing literature on repulsive–attractive nonlocal interaction models, where the repulsive effects instead arise from an interaction kernel or the addition of diffusion. We formulate our model as the Wasserstein gradient flow of an interaction energy, with a penalization to enforce the constraint on the height of the density. From this perspective, the problem can be seen as a singular limit of the Keller–Segel equation with degenerate diffusion. Two key properties distinguish our problem from previous work on height constrained equations: nonconvexity of the interaction kernel (which places the model outside the scope of classical gradient flow theory) and nonlocal dependence of the velocity field on the density (which causes the problem to lack a comparison principle). To overcome these obstacles, we combine recent results on gradient flows of nonconvex energies with viscosity solution theory. We characterize the dynamics of patch solutions in terms of a Hele-Shaw type free boundary problem and, using this characterization, show that in two dimensions patch solutions converge to a characteristic function of a disk in the long-time limit, with an explicit rate on the decay of the energy. We believe that a key contribution of the present work is our blended approach, combining energy methods with viscosity solution theory.
Spectroscopic evidence for temperature-dependent convergence of light and heavy hole valence bands of PbQ (Q=Te, Se, S)

We have conducted a temperature-dependent angle-resolved photoemission spectroscopy (ARPES) study of the electronic structures of PbTe, PbSe and PbS. Our ARPES data provide direct evidence for the light -hole upper valence bands (UVBs) and hitherto undetected heavy -hole lower valence bands (LVBs) in these materials. An unusual temperature-dependent relative movement between these bands leads to a monotonic decrease in the energy separation between their maxima with increasing temperature, which is known as band convergence and has long been believed to be the driving factor behind extraordinary thermoelectric performances of these compounds at elevated temperatures.
When can quantum decoherence be mimicked by classical noise

Quantum decoherence arises due to uncontrollable entanglement between a system and its environment. However, the effects of decoherence are often thought of and modeled through a simpler picture in which the role of the environment is to introduce classical noise in the system's degrees of freedom. Here, we establish necessary conditions that the classical noise models need to satisfy to quantitatively model the decoherence. Specifically, for pure-dephasing processes, we identify well-defined statistical properties for the noise that are determined by the quantum many-point time correlation function of the environmental operators that enter into the system-bath interaction. In particular, for the exemplifying spin-boson problem with a Lorentz-Drude spectral density, we show that the high-temperature quantum decoherence is quantitatively mimicked by colored Gaussian noise. In turn, for dissipative environments, we show that classical noise models cannot describe decoherence effects due to relaxation through spontaneous emission of photons/phonons. These developments provide a rigorous platform to assess the validity of classical noise models of decoherence.
The LIGO Open Science Center

The LIGO Open Science Center (LOSC) fulfills LIGO's commitment to release, archive, and serve LIGO data in a broadly accessible way to the scientific community and to the public, and to provide the information and tools necessary to understand and use the data. In August 2014, the LOSC published the full dataset from Initial LIGO's "S5" run at design sensitivity, the first such large-scale release and a valuable testbed to explore the use of LIGO data by non-LIGO researchers and by the public, and to help teach gravitational-wave data analysis to students across the world. In addition to serving the S5 data, the LOSC web portal (losc.ligo.org) now offers documentation, data-location and data-quality queries, tutorials and example code, and more. We review the mission and plans of the LOSC, focusing on the S5 data release.
Anisotropic-Exchange Magnets on a Triangular Lattice: Spin Waves, Accidental Degeneracies, and Dual Spin Liquids

Author(s): Maksimov, PA; Zhu, Z; White, SR; Chernyshev, AL | Abstract: We present an extensive overview of the phase diagram, spin-wave excitations, and finite-temperature transitions of the anisotropic-exchange magnets on an ideal nearest-neighbor triangular lattice. We investigate transitions between five principal classical phases of the corresponding model: ferromagnetic, Neel, its dual, and the two stripe phases. Transitions are identified by the spin-wave instabilities and by the Luttinger-Tisza approach, and we highlight the benefits of the former while outlining the shortcomings of the latter. Some of the transitions are direct and others occur via intermediate phases with more complicated forms of ordering. The spin-wave spectrum in the Neel phase is obtained and is shown to be nonreciprocal, α,k≠α,-k, in the presence of anisotropic bond-dependent interactions. In a portion of the Neel phase, we find spin-wave instabilities to a long-range spiral-like state. This transition boundary is similar to that of the spin-liquid phase of the S=1/2 model discovered in our prior work, suggesting a possible connection between the two. Further, in the stripe phases, quantum fluctuations are mostly negligible, leaving the ordered moment nearly saturated even for the S=1/2 case. However, for a two-dimensional surface of the full 3D parameter space, the spin-wave spectrum in one of the stripe phases exhibits an enigmatic accidental degeneracy manifested by pseudo-Goldstone modes. As a result, despite the nearly classical ground state, the ordering transition temperature in a wide region of the phase diagram is significantly suppressed from the mean-field expectation. We identify this accidental degeneracy as due to an exact correspondence to an extended Kitaev-Heisenberg model with emergent symmetries that naturally lead to the pseudo-Goldstone modes. There are previously studied dualities within the Kitaev-Heisenberg model on the triangular lattice that are exposed here in a wider parameter space. One important implication of this correspondence for the S=1/2 case is the existence of a region of the spin-liquid phase that is dual to the spin-liquid phase discovered recently by us. We complement our studies by the density-matrix renormalization group of the S=1/2 model to confirm some of the duality relations and to verify the existence of the dual spin-liquid phase.
Quasigeodesic flows and sphere-filling curves

Given a closed hyperbolic 3-manifold M with a quasigeodesic flow we construct a \pi_1-equivariant sphere-filling curve in the boundary of hyperbolic space. Specifically, we show that any complete transversal P to the lifted flow on H^3 has a natural compactification as a closed disc that inherits a \pi_1 action. The embedding of P in H^3 extends continuously to the compactification and the restriction to the boundary is a surjective \pi_1-equivariant map from S^1 to S^2_\infty. This generalizes the result of Cannon and Thurston for fibered hyperbolic 3-manifolds.
Gravitational Wave Frequencies and Energies in Hypernovae

A torus develops a state of suspended accretion against a magnetic wall around a rapidly rotating black hole formed in core-collapse hypernovae. It hereby emits about 10% of the black hole spin energy in gravitational radiation from a finite number of multipole mass moments. We quantify the relation between the frequency of quadrupole gravitational radiation and the energy output Ew in torus winds by fgw 470 Hz(Ew/4 × 1052 ergs)1/2(7 M☉/M)3/2, where M denotes the mass of the black hole. We propose that Ew irradiates the remnant stellar envelope from within. We identify Ew with energies ~ 1052 ergs inferred from X-ray observations on matter injecta and the poloidal curvature in the magnetic wall with the horizon opening angle in baryon poor outflows that power true GRB energies of Eγ 3 × 1051 ergs.
SLATER DECOMPOSITION OF LAUGHLIN STATES

The second-quantized form of the Laughlin states for the fractional quantum Hall effect is discussed by decomposing the Laughlin wavefunctions into the N-particle Slater basis. A general formula is given for the expansion coefficients in terms of the characters of the symmetric group, and the expansion coefficients are shown to possess numerous interesting symmetries. For expectation values of the density operator it is possible to identify individual dominant Slater states of the correct uniform bulk density and filling fraction in the physically relevant N→∞ limit.
First Measurements of the Flux Integral With the NIST-4 Watt Balance

In early 2014, construction of a new watt balance, named NIST-4, had started at the National Institute of Standards and Technology (NIST). In a watt balance, the gravitational force of an unknown mass is compensated by an electromagnetic force produced by a coil in a magnet system. The electromagnetic force depends on the current in the coil and the magnetic flux integral. Most watt balances feature an additional calibration mode, referred to as velocity mode, which allows one to measure the magnetic flux integral to high precision. In this paper, we describe first measurements of the flux integral in the new watt balance. We introduce measurement and data analysis techniques to assess the quality of the measurements and the adverse effects of vibrations on the instrument.
Exact non-symmetric closed line vacuum magnetic fields in a topological torus

Non-symmetric vacuum magnetic fields with closed magnetic field lines are of interest in the construction of stellarator equilibria. Beyond the result of D. Lortz, Z. Angew Math. Phys. 21, 196 (1970), few results are available. This work presents a closed-form expression for a class of vacuum magnetic fields in a topological torus with closed field lines. We explicitly obtain the invariants of such a field. We finally show that a three-dimensional low beta magnetohydrodynamic equilibrium may be constructed in a topological torus, starting with these closed line vacuum magnetic fields.
Materials Relevant to Realizing a Field-Effect Transistor Based on Spin–Orbit Torques

Spin–orbit torque (SOT) is a promising mechanism for writing magnetic memories, while field-effect transistors (FETs) are the gold-standard device for logic operation. The spin–orbit torque field-effect transistor (SOTFET) is a proposed device that couples an SOT-controlled ferromagnet to a semiconducting transistor channel via the transduction in a magnetoelectric multiferroic (MF). This allows the SOTFET to operate as both a memory and a logic device, but its realization depends on the choice of appropriate materials. In this report, we discuss and parametrize the types of materials that can lead to an SOTFET heterostructure.
Markets for public decision-making

A public decision-making problem consists of a set of issues, each with multiple possible alternatives, and a set of competing agents, each with a preferred alternative for each issue. We study adaptations of market economies to this setting, focusing on binary issues. Issues have prices, and each agent is endowed with artificial currency that she can use to purchase probability for her preferred alternatives (we allow randomized outcomes). We first show that when each issue has a single price that is common to all agents, market equilibria can be arbitrarily bad. This negative result motivates a different approach. We present a novel technique called pairwise issue expansion, which transforms any public decision-making instance into an equivalent Fisher market, the simplest type of private goods market. This is done by expanding each issue into many goods: one for each pair of agents who disagree on that issue. We show that the equilibrium prices in the constructed Fisher market yield a pairwise pricing equilibrium in the original public decision-making problem which maximizes Nash welfare. More broadly, pairwise issue expansion uncovers a powerful connection between the public decision-making and private goods settings; this immediately yields several interesting results about public decisions markets, and furthers the hope that we will be able to find a simple iterative voting protocol that leads to near-optimum decisions.
Faddeev–Jackiw Hamiltonian reduction for free and gauged Rarita–Schwinger theories

We study the Faddeev–Jackiw symplectic Hamiltonian reduction for \(3+1\)-dimensional free and Abelian gauged Rarita–Schwinger theories that comprise Grassmannian fermionic fields. We obtain the relevant fundamental brackets and find that they are in convenient forms for quantization. The brackets are independent of whether the theories contain mass or gauge fields, and the structures of constraints and symplectic potentials largely determine characteristic behaviors of the theories. We also note that, in contrast to the free massive theory, the Dirac field equations for free massless Rarita–Schwinger theory cannot be obtained in a covariant way.
Global self-similar protostellar disk/wind models

The magnetocentrifugal disk wind mechanism is the leading candidate for producing the large-scale, bipolar jets commonly seen in protostellar systems. I present a detailed formulation of a global, radially self-similar model for a non-ideal disk that launches a magnetocentrifugal wind. This formulation generalizes the conductivity tensor formalism previously used in radially localized disk models. The model involves matching a solution of the equations of non-ideal magnetohydrodynamics (MHD) describing matter in the disk to a solution of the equations of ideal MHD describing a "cold" wind. The disk solution must pass smoothly through the sonic point, the wind solution must pass smoothly through the Alfven point, and the two solutions must match at the disk/wind interface. This model includes for the first time a self-consistent treatment of the evolution of magnetic flux threading the disk, which can change on the disk accretion timescale. The formulation presented here also allows a realistic conductivity profile for the disk to be used in a global disk/wind model for the first time. The physical constraints on the model solutions fix the distribution of the magnetic field threading the disk, the midplane accretion speed, and the midplane migration speed of flux surfaces. I present a representative solution that corresponds to a disk in the ambipolar conductivity regime with a nominal neutral-matter-magnetic-field coupling parameter that is constant along field lines, matched to a wind solution. I conclude with a brief discussion of the importance of self-similar disk/wind models in studying global processes such as dust evolution in protostellar systems.
Higher Moments of Arithmetic Functions in Short Intervals: A Geometric Perspective

We study the geometry associated to the distribution of certain arithmetic functions, including the von Mangoldt function and the Mobius function, in short intervals of polynomials over a finite field $\mathbb{F}_q$. Using the Grothendieck-Lefschetz trace formula, we reinterpret each moment of these distributions as a point-counting problem on a highly singular complete intersection variety. We compute part of the $\ell$-adic cohomology of these varieties, corresponding to an asymptotic bound on each moment for fixed degree $n$ in the limit as $q \to \infty$. The results of this paper can be viewed as a geometric explanation for asymptotic results that can be proved using analytic number theory over function fields.
Acoustic tomography of solar convective flows and structures

We present a new method for helioseismic diagnostics of the three-dimensional structure of sound speed, magnetic fields and flow velocities in the convection zone by inversion of acoustic travel-time data. The data are measurements of the time for acoustic waves to travel between points on the solar surface and surrounding annuli obtained from continuous observations at the South Pole in 1991 and from high-resolution observations from the Solar and Heliospheric Observatory (SOHO) in 1996. The travel time of the waves depends primarily on the sound speed perturbations and the velocity of flow along the ray paths. The effects of the sound speed perturbations and flows can be separated by measuring the travel time of waves propagating in opposite directions along the same ray paths. Magnetic fields result in anisotropy of the wave speed. A 3D inversion method based on Fermat’s Principle and a regularized least-squares technique have been applied to infer the properties of convection in the quiet Sun and in active regions.
Network brokerage and the perception of leadership

Abstract We renovate a classic experiment to define a research platform that provides data on network behavior and the causal effect of access to structural holes. Our hypothesis is that people are perceived to be leaders when they behave as network brokers, which is to say, when they coordinate information across structural holes. We focus on the perception of leadership to connect with the many field studies in which access to structural holes predicts success measures keyed to leadership. Our hypothesis is clearly supported. The broker-leader association we report is very similar in strength and form to broker-success associations reported in previous research. At the same time, it is also clear that people adapt to their randomly assigned network, re-shaping it to suit preferences that in some part emerge in team deliberations or outside the experiment. A modification to our hypothesis — at least for these small laboratory teams — is that monopoly brokerage is key to being cited as team leader. Leadership is ambiguous when multiple people are positioned to be brokers unless one person emerges by his or her network behavior as a monopoly broker. Our summary conclusion is that access to structural holes can be causal to the perception of leadership, a characteristic implicit in many success measures used to document the broker-success association.
A simplified SARS-CoV-2 detection protocol for research laboratories.

Widespread testing is required to limit the current public health crisis caused by the COVID-19 pandemic. Multiple tests protocols have been authorized by the food and drugs administration (FDA) under an emergency use authorization (EUA). The majority of these protocols are based on the gold-standard RT-qPCR test pioneered by the U.S. Centers for Disease Control and Prevention (CDC). However, there is still a widespread lack of testing in the US and many of the clinical diagnostics protocols require extensive human labor and materials that could face supply shortages and present biosafety concerns. Given the need to develop alternative reagents and approaches to provide nucleic-acid testing in the face of heightened demand and potential shortages, we have developed a simplified SARS-CoV-2 testing protocol adapted for its use in research laboratories with minimal molecular biology equipment and expertise. The protocol utilizes TRIzol to purify the viral RNA from different types of clinical specimens, requires minimal BSL-1 precautions and, given its high sensitivity, can be easily adapted to pooling samples strategies.
EikoNet: Solving the Eikonal Equation With Deep Neural Networks

The recent deep learning revolution has created enormous opportunities for accelerating compute capabilities in the context of physics-based simulations. In this article, we propose EikoNet, a deep learning approach to solving the Eikonal equation, which characterizes the first-arrival-time field in heterogeneous 3-D velocity structures. Our grid-free approach allows for rapid determination of the travel time between any two points within a continuous 3-D domain. These travel time solutions are allowed to violate the differential equation--which casts the problem as one of optimization--with the goal of finding network parameters that minimize the degree to which the equation is violated. In doing so, the method exploits the differentiability of neural networks to calculate the spatial gradients analytically, meaning that the network can be trained on its own without ever needing solutions from a finite-difference algorithm. EikoNet is rigorously tested on several velocity models and sampling methods to demonstrate robustness and versatility. Training and inference are highly parallelized, making the approach well-suited for GPUs. EikoNet has low memory overhead and further avoids the need for travel-time lookup tables. The developed approach has important applications to earthquake hypocenter inversion, ray multipathing, and tomographic modeling, as well as to other fields beyond seismology where ray tracing is essential.
Scalable multiple whole-genome alignment and locally collinear block construction with SibeliaZ

Multiple whole-genome alignment is a challenging problem in bioinformatics. Despite many successes, current methods are not able to keep up with the growing number, length, and complexity of assembled genomes, especially when computational resources are limited. Approaches based on compacted de Bruijn graphs to identify and extend anchors into locally collinear blocks have potential for scalability, but current methods do not scale to mammalian genomes. We present an algorithm, SibeliaZ-LCB, for identifying collinear blocks in closely related genomes based on analysis of the de Bruijn graph. We further incorporate this into a multiple whole-genome alignment pipeline called SibeliaZ. SibeliaZ shows run-time improvements over other methods while maintaining accuracy. On sixteen recently-assembled strains of mice, SibeliaZ runs in under 16 hours on a single machine, while other tools did not run to completion for eight mice within a week. SibeliaZ makes a significant step towards improving scalability of multiple whole-genome alignment and collinear block reconstruction algorithms on a single machine. Multiple whole-genome alignment is a challenging problem in bioinformatics, especially when computational resources are limited. Here the authors present SibeliaZ, an algorithm and software based on analysis of de Bruijn graphs, which provides improved computational efficiency and scalability.
Simulation of coupled multiphase flow and geomechanics in porous media with embedded discrete fractures

In fractured natural formations, the equations governing fluid flow and geomechanics are strongly coupled. Hydrodynamical properties depend on the mechanical configuration, and they are therefore difficult to accurately resolve using uncoupled methods. In recent years, significant research has focused on discretization strategies for these coupled systems, particularly in the presence of complicated fracture network geometries. In this work, we explore a finite-volume discretization for the multiphase flow equations coupled with a finite-element scheme for the mechanical equations. Fractures are treated as lower dimensional surfaces embedded in a background grid. Interactions are captured using the Embedded Discrete Fracture Model (EDFM) and the Embedded Finite Element Method (EFEM) for the flow and the mechanics, respectively. This non-conforming approach significantly alleviates meshing challenges. EDFM considers fractures as lower dimension finiten volumes which exchange fluxes with the rock matrix cells. The EFEM method provides, instead, a local enrichment of the finite-element space inside each matrix cell cut by a fracture element. Both the use of piecewise constant and piecewise linear enrichments are investigated. They are also compared to an Extended Finite Element (XFEM) approach. One key advantage of EFEM is the element-based nature of the enrichment, which reduces the geometric complexity of the implementation and leads to linear systems with advantageous properties. Synthetic numerical tests are presented to study the convergence and accuracy of the proposed method. It is also applied to a realistic scenario, involving a heterogeneous reservoir with a complex fracture distribution, to demonstrate its relevance for field applications.
Welfare costs of bilateral currency crises: The role of international trade

This paper shows that bilateral currency crises reduce bilateral trade up to 50% after controlling for the depreciation rate. Using a trade model, these reductions are connected to the welfare costs of currency crises. The results show that a single currency crisis can result in welfare reductions through changes in international trade corresponding to more than 10% (and up to 41%) of the costs of autarky for 23 different currency crisis episodes between 1960 and 2014. These welfare costs are also shown to be greater than the welfare gains from having free trade agreements and using common currencies for 25 different currency crisis episodes.
Formaldehyde-doxorubicin dual polymeric drug delivery system for higher efficacy and limited cardiotoxicity of anthracyclines

Abstract We report the synthesis of a dual delivery system composed of chemically bound pH-responsive formaldehyde polymer prodrugs and pH-responsive doxorubicin loaded nanoparticles to increase the therapeutic index of doxorubicin by working in synergy with formaldehyde to enable the formation of DOX-DNA adducts and limiting the cardiotoxicity of anthracyclines. Polyacrylates bearing 1,2- and 1,3- pendant diols were synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization to conjugate formaldehyde, forming 5- or 6-membered acetal rings with tunable conjugation percentages (1.5–10 wt%) for controlled release in acidic environments of the tumor extracellular matrix. The formaldehyde-conjugated prodrugs are then combined with polyester nanoparticles formed by intermolecular crosslinking via oxime click chemistry of less than 200 nm in size containing 14 wt% encapsulated Doxorubicin (DOX). Release kinetics show a sustained release of both DOX and formaldehyde at pH 5.0, mimicking the low pH of the tumor environment whereas insignificant release was recorded at physiological pH. The cell viability of the dual delivery system combination was evaluated in 4 T1 breast cancer cells resulting in a considerably increase of cell death of about 4-fold compared to free DOX alone. The protective effect of formaldehyde towards DOX- induced damages was observed in Lactate dehydrogenase assays with cardiomyocytes (P1-3). The resulting polymeric delivery system is the first reported example of a DOX and formaldehyde co-administration, demonstrating the potential significant effect of formaldehyde towards an improved anti-cancer efficacy and reduced cardiotoxicity of DOX.
The relationship between cannabis use and cognition in people with bipolar disorder: A systematic scoping review

Abstract Bipolar disorder (BD) and cannabis use are highly comorbid and are each associated with cognitive impairment. Given the prevalence of cannabis use in people with BD, it is important to understand whether the two interact to impact cognitive function. We performed a systematic scoping review to determine what is currently known in this field. We systematically searched PubMed, Embase, CINAHL, Web of Science, and PsycINFO for studies on the relationship between cannabis use and cognition in people with BD or relevant animal models. Six observational human studies and no animal studies met inclusion criteria. Two studies found cannabis use in BD was associated with better performance in some cognitive domains, while three studies found no association. One study found cannabis use in BD was associated with worse overall cognition. Overall, most identified studies suggest cannabis use is not associated with significant cognitive impairment in BD; however, the scope of knowledge in this field is limited, and more systematic studies are clearly required. Future studies should focus on longitudinal and experimental trials, and well-controlled observational studies with rigorous quantification of the onset, frequency, quantity, duration, and type of cannabis use, as well as BD illness features.
Learning to Satisfy Unknown Constraints in Iterative MPC

We propose a control design method for linear time-invariant systems that iteratively learns to satisfy unknown polyhedral state constraints. At each iteration of a repetitive task, the method constructs an estimate of the unknown environment constraints using collected closed-loop trajectory data. This estimated constraint set is improved iteratively upon collection of additional data. An MPC controller is then designed to robustly satisfy the estimated constraint set. This paper presents the details of the proposed approach, and provides robust and probabilistic guarantees of constraint satisfaction as a function of the number of executed task iterations. We demonstrate the safety of the proposed framework and explore the safety vs. performance trade-off in a numerical example.
Using Social Science to Inform the Law of Intestacy: The Case of Unmarried Committed Partners

Laws of intestate succession determine how the estate of a person who dies without a will is distributed. Researchers have struggled with the question of how to infer the donative intent of persons who die intestate. Based on an empirical study of unmarried committed partners, we compare the usefulness of two methods of social research for informing intestacy law: will studies and interviews with living persons about their preferences for estate distribution. The results indicate that for some groups of unmarried committed partners, will studies may not adequately reflect the extent to which intestate decedents wish their partner to share in their estate. In addition, the results demonstrate a close correspondence between respondents' actual wills, when they had them, and their distributive preferences on hypothetical scenarios. These findings are discussed as they relate to an examination of which sources of social scientific evidence are most useful in informing the law of intestacy.
Witchcraft beliefs and the erosion of social capital: Evidence from Sub-Saharan Africa and beyond

This paper examines the relationship between witchcraft beliefs, a deep-rooted cultural phenomenon, and various elements of social capital. Using novel survey data from nineteen countries in Sub-Saharan Africa we establish a robust negative association between the prevalence of witchcraft beliefs and multiple measures of trust which holds after accounting for country fixed effects and potential confounding factors at the individual, regional, and ethnic-group levels. This finding extends to other metrics of social capital, namely charitable giving and participation in religious group activities. Such coexistence of witchcraft beliefs and antisocial attitudes stands in stark contrast to a well-explored alternative cultural equilibrium characterized by religious prosociality. Evidence from societies beyond Africa shows that in preindustrial communities where witchcraft is believed to be an important cause of illness, mistrust and other antisocial traits are inculcated since childhood. Furthermore, second-generation immigrants in Europe originating from countries with widespread witchcraft beliefs are generally less trusting.
Citations in Economics: Measurement, Uses and Impacts

I describe and compare sources of data on citations in economics and the statistics derived from them. Constructing data sets of the post-publication citation histories of articles published in the "top five" journals in the 1970s and 2000s, I examine distributions and life cycles of citations, compare citation histories of articles in different subspecialties in economics, and present evidence on the history and heterogeneity of those journals' impacts and the marginal citation productivity of additional coauthors. I use a new data set of the lifetime citation histories of over 1,000 economists from thirty universities to rank economics departments by various measures and demonstrate the importance of intra- and interdepartmental heterogeneity in productivity. Throughout, the discussion summarizes earlier work, including the impacts of citations on salaries and nonmonetary rewards, and how citations reflect judgments about research quality in economics and the importance of economic ideas.
Liberty versus Property? Cracks in the Foundations of Copyright Law

Many modern intellectual property scholars have argued that the creation of patents and copyrights, for inventions and writings, respectively, should be resisted on the grounds that these forms of property necessarily infringe ordinary forms of liberty, in contrast to property that is found in tangible things. This article rejects that claim by showing how property conflicts with liberty in both settings, but that the different configurations of rights observed in these various areas is defensible on the grounds that the loss of liberty for all persons is, to the extent that human institutions can make it, compensated by the increased utility generated by the various property rights in question. The appropriate approach to intellectual property is not abolition but fine-tuning in an effort to increase the gains from intellectual property generally.
Three prejudices against terrorism

This article criticises three assumptions regarding terrorism and the agents who carry it out: (1) terrorists are always indiscriminate in their targeting; (2) terrorism is never effective in combating oppression; and (3) terrorists never participate in fair negotiations, as they merely wish to switch places with their oppressors. By criticising these three prejudices against terrorism, the article does not attempt to justify or excuse terrorism generally nor in the specific case of Sri Lanka which is examined. Instead, it creates the necessary room for such justifications or excuses to be critically appraised by dismantling some popular myths surrounding terrorism.
Computation of asymmetric signal extraction filters and mean squared error for ARIMA component models

. Standard signal extraction results for both stationary and nonstationary time series are expressed as linear filters applied to the observed series. Computation of the filter weights, and of the corresponding frequency response function, is relevant for studying properties of the filter and of the resulting signal extraction estimates. Methods for doing such computations for symmetric, doubly infinite filters are well established. This study develops an algorithm for computing filter weights for asymmetric, semi-infinite signal extraction filters, including the important case of the concurrent filter (for signal extraction at the current time point). The setting is where the time series components being estimated follow autoregressive integrated moving-average (ARIMA) models. The algorithm provides expressions for the asymmetric signal extraction filters as rational polynomial functions of the backshift operator. The filter weights are then readily generated by simple expansion of these expressions, and the corresponding frequency response function is directly evaluated. Recursive expressions are also developed that relate the weights for filters that use successively increasing amounts of data. The results for the filter weights are then used to develop methods for computing mean squared error results for the asymmetric signal extraction estimates.
Using Johnson v. United States to Reframe Retroactivity for Second or Successive Collateral Challenges

The Armed Career Criminal Act (ACCA) provides a fifteen-year mandatory minimum sentence in federal prison for persons with at least three prior "violent felony" convictions who are subsequently convicted of being in possession of a firearm. In Johnson v. United States, the U.S. Supreme Court struck down one portion of this statute on the ground that it was unconstitutionally vague. In addition to an enumerated list of "violent felonies" that can result in a conviction, this portion included a catchall category that defined a violent felony as a crime that "otherwise involves conduct that presents a serious potential risk of physical injury to another." This Note examines whether federal prisoners, whose convictions and sentences under this now-unconstitutional prong of the ACCA were final before Johnson, and who have previously petitioned for habeas corpus, may again petition in federal court based on Johnson's holding. In other words, the question, which has become the subject of a widening circuit split and is under review by the Supreme Court, is whether Johnson's new rule about the unconstitutionality of the ACCA has been "made retroactive... by the Supreme Court" to federal prisoners seeking habeas corpus relief in federal court. This Note addresses this question and the circuit split that has emerged on the issue and concludes that Johnson has indeed been "made retroactive." Finally, this Note offers a modified framework for assessing the retroactivity of new rules to second or successive habeas petitions. Language: en
Truth in Gaming: Toward Consumer Protection in the Gambling Industry

This article proposes a new regulatory regime, Truth in Gaming, designed to aid both recreational and problem gamblers alike, and based on the clear, accurate, and timely disclosure of the true costs of gambling. This proposal is based on research that indicates that pathological gamblers often engage in defective gambling strategies, misjudging their inability to control random events and evaluate their losses. The provision of accurate information about the true costs of gambling and the likelihood of losing may aid pathological and problem gamblers in their efforts to gain control over their gambling habits. Such information is crucial to providing consumer protection for gamblers, giving them the information they need to make informed decisions about whether, where, how often, and how much they gamble. Unfortunately, gamblers are rarely provided with accurate price information for slot machines, and such information for other electronic gaming devices is often difficult for gamblers to determine. This lack of price information prevents gamblers from shopping effectively and so makes the market for gambling inefficient as casinos do not compete based on an obvious price for slot machines. Without this information, even non-problem gamblers may unwittingly take risks they would deem excessive if they knew the extent of those risks. The article proposes a regulatory system, Truth in Gaming, that would require casinos to display accurate price information for slot machines and other gaming opportunities, in a way that is clear and meaningful, and that would be interactive so that it would reflect any changing costs based on, for example, how much money is bet. Each slot machine would display the hold percentage, the expected average loss percentage given the bet, for that machine and also a hold amount, which is the expected average amount lost given the bet. These are the true expected average cost of a bet, and should be disclosed to the gambler before the bet. The article also proposes that gaming devices be configured so that gamblers can track their wins, losses, and hold percentages using smart cards, giving them the ability to accurately determine the true cost of gambling to them. These proposals will force casinos to provide consumers the information that they need to bet rationally.
Focal Conic Flower Textures at Curved Interfaces

The ability of liquid-crystal materials to self-assemble into different structures extends even to the defects in them. Ordered arrays of defect-induced structures are used in optical applications, such as microlenses. By inserting colloid particles---which behave as defects---into layered (smectic) liquid crystals to control molecular alignment, scientists develop a new way of generating and manipulating specific optical ``flower textures'' that may see applications.
Structured autocorrelation matrix estimation for coprime arrays

Abstract A coprime array receiver processes a collection of received-signal snapshots to estimate the autocorrelation matrix of a larger (virtual) uniform linear array, known as coarray. By the received-signal model, this matrix has to be (i) Positive Definite, (ii) Hermitian, (iii) Toeplitz, and (iv) its noise-subspace eigenvalues have to be equal. Existing coarray autocorrelation matrix estimates satisfy a subset of the above conditions. In this work, we propose an optimization framework which offers a novel estimate satisfying all four conditions: we propose to iteratively solve a sequence of distinct structure-optimization problems and show that, upon convergence, we provably obtain a single estimate satisfying (i)-(iv). Numerical studies illustrate that the proposed estimate outperforms standard counterparts, both in autocorrelation matrix estimation error and Direction-of-Arrival estimation.
A Locally Gradient-Preserving Reinitialization for Level Set Functions

The level set method commonly requires a reinitialization of the level set function due to interface motion and deformation. We extend the traditional technique for reinitializing the level set function to a method that preserves the interface gradient. The gradient of the level set function represents the stretching of the interface, which is of critical importance in many physical applications. The proposed locally gradient-preserving reinitialization (LGPR) method involves the solution of three PDEs of Hamilton---Jacobi type in succession; first the signed distance function is found using a traditional reinitialization technique, then the interface gradient is extended into the domain by a transport equation, and finally the new level set function is found by solving a generalized reinitialization equation. We prove the well-posedness of the Hamilton---Jacobi equations, with possibly discontinuous Hamiltonians, and propose numerical schemes for their solutions. A subcell resolution technique is used in the numerical solution of the transport equation to extend data away from the interface directly with high accuracy. The reinitialization technique is computationally inexpensive if the PDEs are solved only in a small band surrounding the interface. As an important application, we show how the LGPR procedure can be used to make possible the local level set approach to the Eulerian Immersed boundary method.
Are Early Stage Investors Biased Against Women

We study whether early stage investors have gender biases using a proprietary data set from AngelList that allows us to observe private interactions between investors and fundraising startups. We find that male investors express less interest in female entrepreneurs compared to observably similar male entrepreneurs. In contrast, female investors express more interest in female entrepreneurs. These findings do not appear to be driven by within-gender screening/monitoring advantages or gender differences in risk preferences. Moreover, the male-led startups that male investors express interest in do not outperform the female-led startups they express interest in—they underperform. Overall, the evidence is consistent with gender biases.
Risk–return trade-off in the pacific basin equity markets

Abstract We conduct an empirical study of risk–return trade-off in fourteen Pacific basin equity markets using several volatility estimators, including five variants of GARCH class, equally weighted rolling window volatility, and mixed data sampling (MIDAS), as well as binormal GARCH (BiN-GARCH) model which allows for non-zero conditional skewness in returns. Our findings imply that the BiN-GARCH model, which allows for time-variation in the conditional skewness and market price of risk, captures the expected positive risk–return relationship in eleven out of fourteen markets studied. In comparison, symmetric skewness models such as MIDAS or GARCH variants fail to capture positive and statistically significant market price of risk estimates. These results provide support for the growing literature on the necessity of modeling conditional higher moments in financial research.
The Financial Power of the Powerless: Socio-Economic Status and Interest Rates under Partial Rule of Law

In advanced economies interest rates vary inversely with the borrower's socio-economic status, which itself depends inversely on default risk. These relationships depend on the impartiality of the law. Where the law is markedly biased in favour of certain groups, the latter will pay a surcharge for capital. Legal power, as measured by privileges before the law, thus undermines financial power, the capacity to borrow cheaply. Developing this argument, this paper also tests it through judicial records from Ottoman Istanbul, 1602-1799. Three privileged Ottoman groups—men, Muslims, and titled elites—all paid relatively high interest rates conditional on various loan characteristics. This article is protected by copyright. All rights reserved.