cssi/SciSciGPT-SciSciNet huggingface dataset:
Dynamics of drop impact on solid surfaces: evolution of impact force and self-similar spreading

We investigate the dynamics of drop impacts on dry solid surfaces. By synchronising high-speed photography with fast force sensing, we simultaneously measure the temporal evolution of the shape and impact force of impacting drops over a wide range of Reynolds numbers ( ). At high , when inertia dominates the impact processes, we show that the early time evolution of impact force follows a square-root scaling, quantitatively agreeing with a recent self-similar theory. This observation provides direct experimental evidence on the existence of upward propagating self-similar pressure fields during the initial impact of liquid drops at high . When viscous forces gradually set in with decreasing , we analyse the early time scaling of the impact force of viscous drops using a perturbation method. The analysis quantitatively matches our experiments and successfully predicts the trends of the maximum impact force and the associated peak time with decreasing . Furthermore, we discuss the influence of viscoelasticity on the temporal signature of impact forces. Last but not least, we also investigate the spreading of liquid drops at high following the initial impact. Particularly, we find an exact parameter-free self-similar solution for the inertia-driven drop spreading, which quantitatively predicts the height of spreading drops at high . The limit of the self-similar approach for drop spreading is also discussed. As such, our study provides a quantitative understanding of the temporal evolution of impact forces across the inertial, viscous and viscoelastic regimes and sheds new light on the self-similar dynamics of drop-impact processes.
A SUZAKU OBSERVATION OF MCG-2-58-22: CONSTRAINING THE GEOMETRY OF THE CIRCUMNUCLEAR MATERIAL

We have analyzed a long-look Suzaku observation of the active galactic nucleus MCG -2-58-22, a type 1.5 Seyfert with very little X-ray absorption in the line of sight and prominent features arising from reflection off circumnuclear material: the Fe line and Compton reflection hump. We place tight constraints on the power-law photon index (Γ = 1.80 ± 0.02), the Compton reflection strength (R = 0.69 ± 0.05), and the Fe K emission line energy centroid and width (E = 6.40 ± 0.02 keV, v FWHM < 7100 km s–1). We find no significant evidence either for emission from strongly ionized Fe, or for a strong, relativistically broadened Fe line, indicating that perhaps there is no radiatively efficient accretion disk very close in to the central black hole. In addition, we test a new self-consistent physical model from Murphy and Yaqoob, the "MYTORUS" model, consisting of a donut-shaped torus of material surrounding the central illuminating source and producing both the Compton hump and the Fe K line emission. From the application of this model we find that the observed spectrum is consistent with a Compton-thick torus of material (column density N H = 3.6+1.3 – 0.8 × 1024 cm–2) lying outside of the line of sight to the nucleus, leaving it bare of X-ray absorption in excess of the Galactic column. We calculate that this material is sufficient to produce all of the Fe line flux without the need for any flux contribution from additional Compton-thin circumnuclear material.
Effect of Streaming Motion of Baryons Relative to Dark Matter on the Formation of the First Stars

We evaluate the effect of a supersonic relative velocity between the baryons and dark matter on the thermal and density evolution of the first gas clouds at z 50. Through a series of cosmological simulations, initialized at z i = 100 with a range of relative streaming velocities and minihalo formation redshifts, we find that the typical streaming velocities will have little effect on the gas evolution. Once the collapse begins, the subsequent evolution of the gas will be nearly indistinguishable from the case of no streaming, and star formation will still proceed in the same way, with no change in the characteristic Pop III stellar masses. Reionization is expected to be dominated by halo masses of 108 M ☉, for which the effect of streaming should be negligible.
Quantum Epidemiology: Operator Growth, Thermal Effects, and SYK

In many-body chaotic systems, the size of an operator generically grows in Heisenberg evolution, which can be measured by certain out-of-time-ordered four-point functions. However, these only provide a coarse probe of the full underlying operator growth structure. In this article we develop a methodology to derive the full growth structure of fermionic systems, that also naturally introduces the effect of finite temperature. We then apply our methodology to the SYK model, which features all-to-all q-body interactions. We derive the full operator growth structure in the large q limit at all temperatures. We see that its temperature dependence has a remarkably simple form consistent with the slowing down of scrambling as temperature is decreased. Furthermore, our finite-temperature scrambling results can be modeled by a modified epidemic model, where the thermal state serves as a vaccinated population, thereby slowing the overall rate of infection.
Critical fluctuations of noisy period-doubling maps

We extend the theory of quasipotentials in dynamical systems by calculating, within a broad class of period-doubling maps, an exact potential for the critical fluctuations of pitchfork bifurcations in the weak noise limit. These far-from-equilibrium fluctuations are described by finite-size mean field theory, placing their static properties in the same universality class as the Ising model on a complete graph. We demonstrate that the effective system size of noisy period-doubling bifurcations exhibits universal scaling behavior along period-doubling routes to chaos.
Absolute Dimensions of the Unevolved F-type Eclipsing Binary BT Vulpeculae

We report extensive differential V-band photometry and high-resolution spectroscopy for the 1.14 day, detached, double-lined eclipsing binary BT Vul (F0+F7). Our radial-velocity monitoring and light curve analysis lead to absolute masses and radii of M1 = 1.5439 +/- 0.0098 MSun and R1 = 1.536 +/- 0.018 RSun for the primary, and M2 = 1.2196 +/- 0.0080 MSun and R2 = 1.151 +/- 0.029 RSun for the secondary. The effective temperatures are 7270 +/- 150 K and 6260 +/- 180 K, respectively. Both stars are rapid rotators, and the orbit is circular. A comparison with stellar evolution models from the MIST series shows excellent agreement with these determinations, for a composition of [Fe/H] = +0.08 and an age of 350 Myr. The two components of BT Vul are very near the zero-age main sequence.
Explicit programming strategies

Software developers solve a diverse and wide range of problems. While software engineering research often focuses on tools to support this problem solving, the strategies that developers use to solve problems are at least as important. In this paper, we offer a novel approach for enabling developers to follow explicit programming strategies that describe how an expert tackles a common programming problem. We define explicit programming strategies, grounding our definition in prior work both within software engineering and in other professions which have adopted more explicit procedures for problem solving. We then present a novel notation called Roboto and a novel strategy tracker tool that explicitly represent programming strategies and frame executing strategies as a collaborative effort between human abilities to make decisions and computer abilities to structure process and persist information. In a formative evaluation, 28 software developers of varying expertise completed a design task and a debugging task. We found that, compared to developers who are free to choose their own strategies, developers given explicit strategies experienced their work as more organized, systematic, and predictable, but also more constrained. Developers using explicit strategies were objectively more successful at the design and debugging tasks. We discuss the implications of Roboto and these findings, envisioning a thriving ecosystem of explicit strategies that accelerate and improve developers’ programming problem solving.
Getting a THUMP from a WIMP

Producing an acceptable thermal relic abundance of dark matter with masses ≫ 102 TeV is a challenge. We propose a novel mechanism where GeV-scale states establish a tiny thermal relic abundance for dark matter, which is later promoted to ultra massive status by a very light scalar. We refer to this dark matter as a THermal Ultra Massive Particle (THUMP). Direct detection of THUMPs can be naturally expected due to large scattering cross sections mediated by low mass states that couple THUMPs to the Standard Model. Our model generically leads to signals for the associated GeV-scale states at accelerator experiments.
Vibrational spectroscopy at atomic resolution with electron impact scattering

Atomic vibrations control all thermally activated processes in materials, including diffusion, heat transport, phase transformations and surface chemistry. Recent developments in scanning transmission electron microscopy (STEM) have enabled nanoscale probing of vibrational modes using electron energy-loss spectroscopy (EELS)1,2. Although atomically resolved analysis is routine in STEM, vibrational spectroscopy employing oscillating dipoles yields signals originating from regions tens of nanometres in size, because the scattering angles are only a few microradians3. Recently, it has been shown that energy-filtered images recorded at high scattering angles display atomic resolution4. Here we show, using conventional on-axis EELS, that non-dipole, impact scattering vibrational signals are present, and exhibit atomic resolution. This on-axis signal shows variations in the spectral peak shape and intensity as the electron probe is scanned across an individual atomic column in a Si sample. Although atomic spatial resolution in coherent elastic scattering will complicate the quantitative interpretation of spectra from crystals, the change in peak shape provides compelling evidence that the vibrational EELS excitation process is highly localized. High spatial resolution is also demonstrated in SiO2, an amorphous polar material. Our approach represents an important technical advance that will provide new insights into the local thermal, elastic and kinetic properties of materials. Conventional on-axis electron energy-loss spectroscopy can detect vibrational modes in crystals and amorphous solids at atomic resolution by isolating the specific signal from the background signal and the dipole contributions.
Dynamic arrival rate estimation for campus Mobility On Demand network graphs

Mobility On Demand (MOD) systems are revolutionizing transportation in urban settings by improving vehicle utilization and reducing parking congestion. A key factor in the success of an MOD system is the ability to measure and respond to real-time customer arrival data. Real time traffic arrival rate data is traditionally difficult to obtain due to the need to install fixed sensors throughout the MOD network. This paper presents a framework for measuring pedestrian traffic arrival rates using sensors onboard the vehicles that make up the MOD fleet. A novel distributed fusion algorithm is presented which combines onboard LIDAR and camera sensor measurements to detect trajectories of pedestrians with a 90% detection hit rate with 1.5 false positives per minute. A novel moving observer method is introduced to estimate pedestrian arrival rates from pedestrian trajectories collected from mobile sensors. The moving observer method is evaluated in both simulation and hardware and is shown to achieve arrival rate estimates comparable to those that would be obtained with multiple stationary sensors.
Astrometric “Imaging” of Crowded Stellar Fields with Only Two SIM Pointings

The Space Interferometry Mission (SIM) will observe sources in crowded fields. Source crowding can induce significant positional errors in SIM's astrometric measurements, even for targets many magnitudes brighter than all other crowding sources. Here we show that the spectral decomposition of the fringe pattern may be used to perform phase and group delay estimation for multiple field sources simultaneously. This allows disentanglement of the overlapping fringes from multiple blended sources, leading to precise astrometric measurements for each source. Effectively, this is synthesis "imaging" of point sources with just two baselines. We find that spectrally dispersed fringes enable SIM to identify and localize a limited number of field sources quite robustly, thereby reducing astrometry errors to near photon noise levels. We simulate SIM measurements of the LMC and show that (1) SIM astrometry will not be corrupted by blending and (2) extremely precise imaging of mildly crowded fields may be performed using only two orthogonal baseline orientations, allowing microarcsecond positional measurements. We lastly illustrate the method's potential with the example of astrometric microlensing, showing that SIM's mass and distance measurements of lenses will be untainted by crowding when spectrally dispersed fringes are measured.
Automatic sequences and curves over finite fields

We prove that if y = ∑ n=0∞a(n)xn ∈ Fq[[x]] is an algebraic power series of degree d, height h, and genus g, then the sequence a is generated by an automaton with at most qh+d+g−1 states, up to a vanishingly small error term. This is a significant improvement on previously known bounds. Our approach follows an idea of David Speyer to connect automata theory with algebraic geometry by representing the transitions in an automaton as twisted Cartier operators on the differentials of a curve.
The Formation of the First Massive Black Holes

Supermassive black holes (SMBHs) are common in local galactic nuclei, and SMBHs as massive as several billion solar masses already exist at redshift z = 6. These earliest SMBHs may grow by the combination of radiation-pressure-limited accretion and mergers of stellar-mass seed BHs, left behind by the first generation of metal-free stars, or may be formed by more rapid direct collapse of gas in rare special environments where dense gas can accumulate without first fragmenting into stars. This chapter offers a review of these two competing scenarios, as well as some more exotic alternative ideas. It also briefly discusses how the different models may be distinguished in the future by observations with JWST, LISA and other instruments.
A SURVEY OF ALKALI LINE ABSORPTION IN EXOPLANETARY ATMOSPHERES

We obtained over 90 hr of spectroscopic observations of four exoplanetary systems with the Hobby‐Eberly Telescope. Observations were taken in transit and out of transit, and we analyzed the differenced spectra—i.e., the transmission spectra—to inspect it for absorption at the wavelengths of the neutral sodium (Nai) doublet at λλ5889,5895 and neutral potassium (Ki )a tλ7698. We used the transmission spectrum at Cai λ6122—which showsstrongstellarabsorptionbutisnotanalkalimetalresonancelinethatweexpecttoshowsignificantabsorption in these atmospheres—as a control line to examine our measurements for systematic errors. We use an empirical Monte Carlo method to quantify these systematic errors. In a reanalysis of the same data set using a reduction and analysis pipeline that was derived independently, we confirm the previously seen Nai absorption in HD 189733b at a level of (−5.26 ± 1.69) × 10 −4 (the average value over a 12 A integration band to be consistent with previous authors). Additionally, we tentatively confirm the Nai absorption seen in HD 209458b (independently by multiple authors) at a level of (−2.63 ± 0.81) × 10 −4 , though the interpretation is less clear. Furthermore, we find Nai absorption of (−3.16 ± 2.06) × 10 −4 at <3σ in HD 149026b; features apparent in the transmission spectrum are consistent with real absorption and indicate this may be a good target for future observations to confirm. No other results (Nai in HD 147506b and Cai and Ki in all four targets) are significant to 3σ, although we observe some features that we argue are primarily artifacts.
An intermediate quasi-isometric invariant between subexponential asymptotic dimension growth and Yu's property A

We present a new quasi-isometric invariant for metric spaces that we name asymptotically large depth. For finitely generated groups we show that this invariant implies Yu's property A and is implied by subexponential asymptotic dimension growth.
The NEXTGEN Model Atmosphere Grid. II. Spherically Symmetric Model Atmospheres for Giant Stars with Effective Temperatures between 3000 and 6800 K

We present the extension of our NextGen model atmosphere grid to the regime of giant stars. The input physics of the models presented here is nearly identical to that of the NextGen dwarf atmosphere models; however, spherical geometry is used self-consistently in the model calculations (including the radiative transfer). We revisit the discussion of the effects of spherical geometry on the structure of the atmospheres and the emitted spectra and discuss the results of non-LTE calculations for a few selected models.
The Origin of Kepler-419b: A Path to Tidal Migration Via Four-body Secular Interactions

We test the high-eccentricity tidal migration scenario for Kepler-419b, a member of the eccentric warm Jupiter class of planets whose origin is debated. Kepler-419 hosts two known planets (b,c). However, in its current configuration, planet c cannot excite the eccentricity of planet b enough to undergo high-eccentricity tidal migration. We investigate whether the presence of an undiscovered fourth body could explain the orbit of Kepler-419b. We explore the parameter space of this potential third giant planet using a suite of N-body simulations with a range of initial conditions. From the results of these simulations, coupled with observational constraints, we can rule out this mechanism for much of the parameter space of the initial object d conditions. However, for a small range of parameters (masses between 0.5 and 7 m Jup, semimajor axes between 4 and 7.5 au, eccentricities between 0.18 and 0.35, and mutual inclinations near 0°) an undiscovered object d could periodically excite the eccentricity of Kepler-419b without destabilizing the system over 1 Gyr while producing currently undetectable radial velocity and transit timing variation signals.
Evidence for Two Hot-Jupiter Formation Paths

Disk migration and high-eccentricity migration are two well-studied theories to explain the formation of hot Jupiters. The former predicts that these planets can migrate up until the planet-star Roche separation ($a_{Roche}$) and the latter predicts they will tidally circularize at a minimum distance of 2$a_{Roche}$. Considering long-running radial velocity and transit surveys have identified a couple hundred hot Jupiters to date, we can revisit the classic question of hot Jupiter formation in a data-driven manner. We approach this problem using data from several exoplanet surveys (radial velocity, Kepler, HAT, and WASP) allowing for either a single population or a mixture of populations associated with these formation channels, and applying a hierarchical Bayesian mixture model of truncated power laws of the form $x^{\gamma-1}$ to constrain the population-level parameters of interest (e.g., location of inner edges, $\gamma$, mixture fractions). Within the limitations of our chosen models, we find the current radial velocity and Kepler sample of hot Jupiters can be well explained with a single truncated power law distribution with a lower cutoff near 2$a_{Roche}$, a result that still holds after a decade, and $\gamma=-0.51\pm^{0.19}_{0.20}$. However, the HAT and WASP data show evidence for multiple populations (Bayes factor $\approx 10^{21}$). We find that $15\pm^{9}_{6}\%$ reside in a component consistent with disk migration ($\gamma=-0.04\pm^{0.53}_{1.27}$) and $85\pm^{6}_{9}\%$ in one consistent with high-eccentricity migration ($\gamma=-1.38\pm^{0.32}_{0.47}$). We find no immediately strong connections with some observed host star properties and speculate on how future exoplanet surveys could improve upon hot Jupiter population inference.
Enhanced superlens imaging with loss-compensating hyperbolic near-field spatial filter

Recently a coherent optical process called plasmon-injection (Π) scheme, which employs an auxiliary source, has been introduced as a new technique to compensate losses in metamaterials. Here, a physical implementation of the Π scheme is proposed for enhanced superlens imaging in the presence of absorption losses and noise. The auxiliary source is constructed by a high-intensity illumination (above 1 mW/μm2) of the superlens integrated with a near-field spatial filter. The integrated system enables reconstruction of an object previously unresolvable with the superlens alone. This work elevates the viability of the Π scheme as a strong candidate for loss compensation in near-field imaging systems without requiring nonlinear effects or gain media.
Tight State-Restoration Soundness in the Algebraic Group Model

Most efficient zero-knowledge arguments lack a concrete security analysis, making parameter choices and efficiency comparisons challenging. This is even more true for non-interactive versions of these systems obtained via the Fiat-Shamir transform, for which the security guarantees generically derived from the interactive protocol are often too weak, even when assuming a random oracle.
Harvesting energy from sun, outer space, and soil

While solar power systems have offered a wide variety of electricity generation approaches including photovoltaics, solar thermal power systems, and solar thermoelectric generators, the ability to generate electricity at both the daytime and nighttime with no necessity of energy storage remains challenging. Here, we propose and verify an environment-friendly, sustainable, and cost-effective strategy of harvesting solar energy by solar heating during the daytime and harnessing the coldness of the outer space through radiative cooling to produce electricity at night using a commercial thermoelectric module. It enables electricity generation for 24 h a day. We experimentally demonstrate a peak power density of 37 mW/m[Formula: see text] at night and a peak value of 723 mW/m[Formula: see text] during the daytime. A theoretical model that accurately predicts the performance of the device is developed and validated. The feature of 24-h electricity generation shows great potential energy applications of off-grid and battery-free lighting and sensing.
CleaNN: accelerated trojan shield for embedded neural networks

We propose Cleann, the first end-to-end framework that enables online mitigation of Trojans for embedded Deep Neural Network (DNN) applications. A Trojan attack works by injecting a backdoor in the DNN while training; during inference, the Trojan can be activated by the specific backdoor trigger. What differentiates Cleann from the prior work is its lightweight methodology which recovers the ground-truth class of Trojan samples without the need for labeled data, model retraining, or prior assumptions on the trigger or the attack. We leverage dictionary learning and sparse approximation to characterize the statistical behavior of benign data and identify Trojan triggers. Cleann is devised based on algorithm/hardware co-design and is equipped with specialized hardware to enable efficient real-time execution on resource-constrained embedded platforms. Proof of concept evaluations on Cleann for the state-of-the-art Neural Trojan attacks on visual benchmarks demonstrate its competitive advantage in terms of attack resiliency and execution overhead.
Enzymatic Analysis of Yeast Cell Wall-Resident GAPDH and Its Secretion.

ABSTRACT In yeast, many proteins are found in both the cytoplasmic and extracellular compartments, and consequently it can be difficult to distinguish nonconventional secretion from cellular leakage. Therefore, we monitored the extracellular glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity of intact cells as a specific marker for nonconventional secretion. Extracellular GAPDH activity was proportional to the number of cells assayed, increased with incubation time, and was dependent on added substrates. Preincubation of intact cells with 100 μM dithiothreitol increased the reaction rate, consistent with increased access of the enzyme after reduction of cell wall disulfide cross-links. Such treatment did not increase cell permeability to propidium iodide, in contrast to effects of higher concentrations of reducing agents. An amine-specific membrane-impermeant biotinylation reagent specifically inactivated extracellular GAPDH. The enzyme was secreted again after a 30- to 60-min lag following the inactivation, and there was no concomitant increase in propidium iodide staining. There were about 4 × 104 active GAPDH molecules per cell at steady state, and secretion studies showed replenishment to that level 1 h after inactivation. These results establish conditions for specific quantitative assays of cell wall proteins in the absence of cytoplasmic leakage and for subsequent quantification of secretion rates in intact cells. IMPORTANCE Eukaryotic cells secrete many proteins, including many proteins that do not follow the classical secretion pathway. Among these, the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is unexpectedly found in the walls of yeasts and other fungi and in extracellular space in mammalian cell cultures. It is difficult to quantify extracellular GAPDH, because leakage of just a little of the very large amount of cytoplasmic enzyme can invalidate the determinations. We used enzymatic assays of intact cells while also maintaining membrane integrity. The results lead to estimates of the amount of extracellular enzyme and its rate of secretion to the wall in intact cells. Therefore, enzyme assays under controlled conditions can be used to investigate nonconventional secretion more generally.
On the Tu-Zeng permutation trinomial of type (1∕4,3∕4)

Abstract Let q be a power of 2. Recently, Tu and Zeng considered trinomials of the form f ( X ) = X + a X ( 1 ∕ 4 ) q 2 ( q − 1 ) + b X ( 3 ∕ 4 ) q 2 ( q − 1 ) , where a , b ∈ F q 2 ∗ . They proved that f is a permutation polynomial of F q 2 if b = a 2 − q and X 3 + X + a − 1 − q has no root in F q . In this paper, we show that the above sufficient condition is also necessary.
Framework for identifying drug repurposing candidates from observational healthcare data.

Objective Observational medical databases, such as electronic health records and insurance claims, track the healthcare trajectory of millions of individuals. These databases provide real-world longitudinal information on large cohorts of patients and their medication prescription history. We present an easy-to-customize framework that systematically analyzes such databases to identify new indications for on-market prescription drugs. Materials and methods Our framework provides an interface for defining study design parameters and extracting patient cohorts, disease-related outcomes, and potential confounders in observational databases. It then applies causal inference methodology to emulate hundreds of randomized controlled trials (RCTs) for prescribed drugs, while adjusting for confounding and selection biases. After correcting for multiple testing, it outputs the estimated effects and their statistical significance in each database. Results We demonstrate the utility of the framework in a case study of Parkinson's disease (PD) and evaluate the effect of 259 drugs on various PD progression measures in two observational medical databases, covering more than 150 million patients. The results of these emulated trials reveal remarkable agreement between the two databases for the most promising candidates. Discussion Estimating drug effects from observational data is challenging due to data biases and noise. To tackle this challenge, we integrate causal inference methodology with domain knowledge and compare the estimated effects in two separate databases. Conclusion Our framework enables systematic search for drug repurposing candidates by emulating RCTs using observational data. The high level of agreement between separate databases strongly supports the identified effects.
One-Way Functions Imply Secure Computation in a Quantum World

We prove that quantum-hard one-way functions imply simulation-secure quantum oblivious transfer (QOT), which is known to suffice for secure computation of arbitrary quantum functionalities. Furthermore, our construction only makes black-box use of the quantum-hard one-way function.
MPC-Based Hierarchical Task Space Control of Underactuated and Constrained Robots for Execution of Multiple Tasks

This paper proposes an MPC-based controller to efficiently execute multiple hierarchical tasks for underactuated and constrained robotic systems. Existing task-space controllers or whole-body controllers solve instantaneous optimization problems given task trajectories and the robot plant dynamics. However, the task-space control method we propose here relies on the prediction of future state trajectories and the corresponding costs-to-go terms over a finite time-horizon for computing control commands. We employ acceleration energy error as the performance index for the optimization problem and extend it over the finite-time horizon of our MPC. Our approach employs quadratically constrained quadratic programming, which includes quadratic constraints to handle multiple hierarchical tasks, and is computationally more efficient than nonlinear MPC-based approaches that rely on nonlinear programming. We validate our approach using numerical simulations of a new type of robot manipulator system, which contains underactuated and constrained mechanical structures.
Robust Closed-loop Model Predictive Control via System Level Synthesis

In this paper, we consider the robust closed-loop model predictive control (MPC) of a linear time-variant (LTV) system with norm bounded disturbances and LTV model uncertainty, wherein a series of constrained optimal control problems (OCPs) are solved. Guaranteeing robust feasibility of these OCPs is challenging due to disturbances perturbing the predicted states, and model uncertainty, both of which can render the closed-loop system unstable. As such, a trade-off between the numerical tractability and conservativeness of the solutions is often required. We use the System Level Synthesis (SLS) framework to reformulate these constrained OCPs over closed-loop system responses, and show that this allows us to transparently account for norm bounded additive disturbances and LTV model uncertainty by computing robust state feedback policies. We further show that by exploiting the underlying linear fractional structure of the resulting robust OCPs, we can significantly reduce the conservativeness of existing SLS-based and tube-MPC-based robust control methods while also improving computational efficiency. We conclude with numerical examples demonstrating the effectiveness of our methods.
Action Duration Prediction for Segment-Level Alignment of Weakly-Labeled Videos

This paper focuses on weakly-supervised action alignment, where only the ordered sequence of video-level actions is available for training. We propose a novel Duration Network1, which captures a short temporal window of the video and learns to predict the remaining duration of a given action at any point in time with a level of granularity based on the type of that action. Further, we introduce a Segment-Level Beam Search to obtain the best alignment, that maximizes our posterior probability. Segment-Level Beam Search efficiently aligns actions by considering only a selected set of frames that have more confident predictions. The experimental results show that our alignments for long videos are more robust than existing models. Moreover, the proposed method achieves state of the art results in certain cases on the popular Breakfast and Hollywood Extended datasets.
ON WARING'S PROBLEM IN SUMS OF THREE CUBES

We investigate the asymptotic formula for the number of representations of a large positive integer as a sum of $k$-th powers of integers represented as the sums of three positive cubes, counted with multiplicities. We also obtain a lower bound for the number of representations when the sums of three cubes are counted without multiplicities.
Improving Causal Inference with Text as Data in Empirical IS Research: A Machine Learning Approach

This study combines two streams of literature – text representation and machine learning-based causal inference, to study how to represent text as data to improve causal inference, i.e., estimating treatment effects more accurately. We choose a real problem context, Yelp reviews, to demonstrate how to train a topic modeling or Word2Vec model to transform review text into meaningful metrics and the causal forest to estimate the treatment effect of an ‘Elite’ badge recognized by Yelp on received votes of the review. Results show that the estimated average treatment effect (ATE) significantly decreases after adding quantitative text representations into the model. This implies that the positive effect of ‘Elite’ badge was overestimated without text information. We also present specific steps to help other researchers leverage the causal forest to estimate the heterogeneous effects across subgroups. Overall, we show that transforming text into quantitative data makes the treatment effect estimation more accurate.
Judges and Juries: The Defense Case and Differences in Acquittal Rates

Kalven and Zeisel's (1966) classic study, The American Jury, concluded that juries were “in revolt” from the law when they acquitted when judges would have convicted. Using data collected by the National Center for State Courts to examine jury decision making in four different communities, this article reexamines the question of the judge and jury's respective fidelity to the law and evidence by examining the influence on judge and jury of the defendant's evidence, his criminal record, and his reason for refusing to plead. No data can tell us definitively whether the judge is correct and the jury in error when they disagree, but the data analyzed in the present study can tell us whether the factors that move the jury and fail to move the judge are or are not consistent with the innocence of the accused.
The United States’ Premature Pivot to “Asia”

The Obama administration has shifted its focus of strategic concerns from the Middle East to the Far East. (Although the term “Asia” is often used, reference is clearly to China, as there is no other power in that region the U.S. holds it must contend with.) The shift reminds one of the old parable about a child who was looking for his lost dime next to the lamp post, not because it was there that the dime went missing—but because it was there that the light made searching easy. Responding to challenges posed by Iran, Pakistan, Afghanistan, Iraq, and the Arab Awakening is extremely taxing and frustrating. Countering China for now does not entail sacrificing the lives of young Americans, no surges are called for (the U.S. plans to send 250 Marines to Australia for now, and up to 2,500 over the next 10 years, and two aircraft carriers—of which the U.S. has eleven—are maneuvering in the area), and no large outlay of funds is needed. Moreover, one can readily point to achievements: several of the nations that border China have chosen to strengthen their ties with the U.S., including Vietnam, the Philippines, and even Burma. And these nations are following the U.S. lead to deal with China as a group, rather than on a one-on-one basis, as China sought. And the region is mainly peaceful and stable. Moreover, the Pentagon has a strong innate preference for preparing for a war with conventional troops: fighting an enemy with fighter planes, ships, artillery, and tanks—rather than dealing with irregular forces, of the sort it faces in the Middle East. The same holds for the lobbies that represent the American corporations that build the hardware. There is much more money to be made by building F-22 s and F-35 s and hundreds more ships to counter China, than by adding Special Forces and manufacturing whatever meager means their warfare requires: snub handguns, sharp knives, and robes. True, China may one day become a major power that will challenge the global role of the U.S. However, if such a development is to take place, it will be decades down the road—while the U.S. is challenged in the Middle East right now. Moreover, the way the U.S. deals with the Middle East has major consequences extending far beyond the region, including for the global stature of the U.S. and—its position in the Far East. The article proceeds by outlining the Middle East challenge and its implications, and then examines several reasons most (albeit not all) of the power moves to contain China can be delayed. Indeed, it might be beneficial to defer them.
Airport noise regulation, airline service quality, and social welfare

This paper explores the impact of airport noise regulation on airline service quality and airfares. It also characterizes the socially optimal stringency of noise limits, taking both noise damage and the various costs borne by airlines and their passengers into account. The analysis also investigates the effect of noise taxes, as well as the optimal level of such taxes. Along with the companion paper by [Girvin, R., 2006a. Airport noise regulation, airline service quality, and social welfare: The monopoly case. Unpublished paper, Program in Transportation Science, UC, Irvine], this work represents the first complete theoretical investigation into the economics of airport noise regulation using a model where the interests of the key relevant stakeholders are captured.
LIMITED ARBITRAGE AND SHORT SALES RESTRICTIONS: EVIDENCE FROM THE OPTIONS MARKETS

Abstract We investigate empirically the well-known put–call parity no-arbitrage relation in the presence of short sales restrictions. Violations of put–call parity are asymmetric in the direction of short sales constraints, and their magnitudes are strongly related to the cost and difficulty of short selling. These violations are also related to both the maturity of the option and the level of valuations in the stock market, consistent with a behavioral finance theory of over-optimistic stock investors and market segmentation. Moreover, both the size of put–call parity violations and the cost of short selling are significant predictors of future returns for individual stocks.
How firms respond to being rated

While many rating systems seek to help buyers overcome information asymmetries when making purchasing decisions, we investigate how these ratings also influence the companies being rated. We hypothesize that ratings are particularly likely to spur responses from firms that receive poor ratings, and especially those that face lower-cost opportunities to improve or that anticipate greater benefits from doing do. We test our hypotheses in the context of corporate environmental ratings that guide investors to select ‘socially responsible,’ and avoid ‘socially irresponsible,’ companies. We examine how several hundred firms responded to corporate environmental ratings issued by a prominent independent social rating agency, and take advantage of an exogenous shock that occurred when the agency expanded the scope of its ratings. Our study is among the first to theorize about the impact of ratings on subsequent performance, and we introduce important contingencies that influence firm response. These theoretical advances inform stakeholder theory, institutional theory, and economic theory. Copyright © 2010 John Wiley & Sons, Ltd.
On the validity of the Girsanov transformation method for sensitivity analysis of stochastic chemical reaction networks

We investigate the validity of the Girsanov Transformation (GT) method for parametric sensitivity analysis of stochastic models of chemical reaction networks. The validity depends on the likelihood...
King v. Burwell: What Does It Portend for Chevron's Domain?

In King v. Burwell, 135 S. Ct. 2480 (2015), the U.S. Supreme Court held that the Premium Tax Credit provisions of the Affordable Care Act (ACA) apply to taxpayers who purchase health insurance products on state and federally facilitated exchanges alike. In so holding, the Court reached the same result that lower courts — and, indeed, Treasury and the IRS — had reached. But the Court’s analytical path in King differed sharply from the approach of the district court and the Fourth Circuit below. Rather than invoking ordinary Chevron principles and evaluating Treasury’s interpretation of the ACA deferentially, the Court conducted its own interpretation of the statute, deciding for itself what the admittedly ambiguous law means and what it requires.This short Essay considers what the King decision suggests about the future of Chevron deference. It first compares the Court’s approach in King with its approach in two other “extraordinary” nondeference cases, FDA v. Brown & Williamson Tobacco Corp. and Gonzales v. Oregon. It next situates King in a broader context of developments in the Court’s Chevron jurisprudence. The Essay concludes that, while King may simply be a sui generis case involving an important social program, it may also signal a fading appetite for deference among the Justices.
Essential Health Benefits and the Affordable Care Act: Law and Process

Starting in 2014, the Affordable Care Act (ACA) will require private insurance plans sold in the individual and small-group markets to cover a roster of "essential health benefits." Precisely which benefits should count as essential, however, was left to the discretion of the Department of Health and Human Services (HHS). The matter was both important and controversial. Nonetheless, HHS announced its policy by posting on the Internet a thirteen-page bulletin stating that it would allow each state to define essential benefits for itself. On both substance and procedure, the move was surprising. The state-by-state approach departed from the uniform, federal standard that the ACA appears to anticipate and that informed observers expected HHS to adopt. And announcing the policy through an Internet bulletin appeared to allow HHS to sidestep traditional administrative procedures, including notice and comment, immediate review in the courts, and White House oversight. This article explores two questions. First, is the state-by-state approach a lawful exercise of HHS's authority? Second, did HHS in fact evade the procedural obligations that are meant to shape the exercise of its discretion?
The World Health Organization's Framework Convention on Tobacco Control: an Analysis of Guidelines Adopted by the Conference of the Parties

Framework treaties are increasingly used to address issue-areas of global concern like climate change, ozone depletion and tobacco control. These treaties provide the general platform for international cooperation while empowering States Parties to develop specific mandates for action through subsequent treaties (protocols) and interim decisions, often in the form of guidelines, by the treaty’s governing body. This Article analyzes guidelines adopted by the Conference of the Parties, the governing body of the World Health Organization’s 2003 Framework Convention on Tobacco Control, for Articles 5.3, 8, 11 and 13 dealing with, respectively, protection of public health policy from tobacco industry interference, protection from exposure to tobacco smoke, packaging and labeling of tobacco products and comprehensive bans of tobacco advertising, promotion and sponsorship. Competing interpretations of treaty and guidelines’ language raises questions about the effect of the guidelines as binding treaty law, customary international law or “soft law.” Applying traditional canons of treaty interpretation, this Article concludes that the guidelines, as decisions of the Conference of the Parties, are a “subsequent agreement regarding the interpretation of the treaty or the application of its provisions.” States Parties are therefore under an obligation to implement treaty provisions in light of the guidelines. While the language of the guidelines is not always mandatory, the guidelines inform the general obligation to comply with the treaty in good faith while specific provisions of the guidelines give rise to mandatory action. The Article also outlines alternative monitoring, enforcement and implementation mechanisms which may give the guidelines force as domestic law. The purpose of the Article is not only to clarify obligations imposed by the FCTC and the COP, but also to offer a comparative lesson as framework treaties increase in use and influence.
Contract Theory and Strategic Management: Balancing Expectations and Actions

Business firms as well as each of their subunits can be thought of as a set of contracts in which participating agents seek their own goals. Participants contribute resources, expecting to receive in exchange more than the opportunity cost of their contributions. For this system to work, the expectations of each individual must be in balance with what he/she is expected to contribute. In addition, the production technology of the firm must be capable of fulfilling such expectations in aggregate. Changes in factor and product markets continually alter the expectations and actions of individuals, nudge them out of balance, and threaten the feasibility of the contract set. A strategic manager scans the relevant markets for incipient changes in environment, and redesigns and implements new contracts which balance the self-interest of individuals with their changing expectations. Redesign and renegotiation of contracts is complicated because people protect their self-interest. Many firms collapse when the managers fail to recognize and act upon the changes in business environment in a timely fashion. Some redesign efforts fail because managers do not elicit the cooperation of those who have the necessary knowledge and expertise and expect to be adversely affected by the proposed changes. The contract model of the firm provides a framework and perspective to reduce such failures.
Tangible and intangible information in emerging markets

High book-to-market stocks earn higher average returns than low book-to-market stocks. This result has been verified using stock returns from the US, developed, and emerging markets. Why B/M explains expected returns is still an open question. In this paper, we use stock returns representing twenty-five emerging markets to test three different theories. Our results differ from papers studying the US stock market. For emerging markets, the component of book-to-market that is related to tangible information (past accounting performance) is significantly related to expected returns while the component related to intangible information (changes in price unrelated to accounting performance) is not. Our evidence is consistent across emerging market regions. We attempt to differentiate between overreaction and risk explanations for the B/M effect. We find some evidence to support overreaction but find no support for the risk explanation.
An Examination of How Entry-Level Staff Auditors Respond to Tone at the Top vis-à-vis Tone at the Bottom

ABSTRACT: Prior academic and practitioner literature argues that the ethical tone at the top of an organization is a key factor in establishing an effective internal control environment. Drawing on self-concept maintenance theory and in-group bias theory, this study predicts that entry-level staff auditors will disregard a company's ethical standards unless they observe a strong ethical tone from both their partner (tone at the top) and their supervising senior (tone at the bottom). Also, this study predicts that staff auditors will be more influenced by the tone of their supervising senior than the partner when these two individuals provide conflicting tones. In a 2 × 2 experiment that manipulates the tone set by a staff auditor's supervising senior and engagement partner, this study provides evidence consistent with predictions. Further analyses suggest that participants make less ethical decisions because they are less likely to view the situation as an ethical dilemma when either the senior or partner...