cssi/SciSciGPT-SciSciNet huggingface dataset:
Divergent Photocatalytic Reactions of α-Ketoesters under Triplet Sensitization and Photoredox Conditions.

The long-lived triplet excited states of transition metal photocatalysts can activate organic substrates via either energy- or electron-transfer pathways, and the rates of these processes can be influenced by rational tuning of the reaction conditions. The characteristic reactive intermediates generated, however, are distinct and can exhibit very different reactivity patterns. This mechanistic diversity available to photocatalytic reactions might thus offer an opportunity to engineer divergent reactions that give markedly different chemical outcomes under superficially similar conditions. Herein, we show that the photocatalytic reactions of benzoylformate esters with alkenes can be directed toward either Paterno-Buchi cycloadditions or allylic functionalization reactions under conditions favoring energy transfer or electron transfer, respectively. These studies provide a framework for designing other divergent photocatalytic methods that produce different sets of reaction outcomes under photoredox and triplet sensitization conditions.
Monotonicity Properties of Physical Network Flows and Application to Robust Optimal Allocation

We derive conditions for monotonicity properties that characterize general flows of a commodity over a network, where the flow is described by potential and flow dynamics on the edges, as well as potential continuity and the Kirchhoff–Neumann mass balance requirements at nodes. The transported commodity may be injected or withdrawn at any of the network nodes, and its movement throughout the network is controlled by nodal actuators. For a class of dissipative nonlinear parabolic partial differential equation (PDE) systems on networks, we derive conditions for monotonicity properties in steady-state flow, as well as for propagation of monotone ordering of states with respect to time-varying boundary condition parameters. In the latter case, initial conditions and time-varying parameters in the coupling conditions at vertices provide an initial boundary value problem (IBVP). We prove that ordering properties of the solution to the IBVP are preserved when the initial conditions and the parameters of the time-varying coupling law are appropriately ordered. Then, we prove that when monotone ordering is not preserved, the first crossing of solutions occurs at a network node. We consider the implications for robust optimization and optimal control formulations and real-time monitoring of uncertain dynamic flows on networks and discuss the application to subsonic compressible fluid flow with energy dissipation on physical networks. The main result and monitoring policy are demonstrated for gas pipeline test networks and a case study using data corresponding to a real working system. We propose applications of this general result to the control and monitoring of natural gas transmission networks.
Particle pair dispersion and eddy diffusivity in a high-speed premixed flame

Abstract Turbulent mixing is a physical process of fundamental importance in high-speed premixed flames. This mixing results in enhanced transport of temperature and chemical scalars, leading to potentially large changes in flame structure and dynamics. To understand turbulent mixing in non-reacting flows, a number of classical theories have been proposed to describe the scaling and statistics of dispersing fluid particle pairs, including predictions of the effective, or turbulent, eddy diffusivity. Here we examine the validity of these classical theories through the study of fluid particle pair dispersion and eddy diffusivity in a highly turbulent premixed methane-air flame at a Karlovitz number of approximately 140. Using data from a direct numerical simulation and a higher-order Lagrangian tracking algorithm, particle pair centroids are seeded at different initial temperatures and separations, and then integrated forward in time. We show that scaling relations and results developed for pair dispersion in non-reacting flows remain relevant in this high-intensity premixed flame, and we identify the impacts of heat release on dispersion and eddy diffusivity.
Climatology of Severe Local Storm Environments and Synoptic-Scale Features over North America in ERA5 Reanalysis and CAM6 Simulation

Severe local storm (SLS) activity is known to occur within specific thermodynamic and kinematic environments. These environments are commonly associated with key synoptic-scale features--including southerly Great Plains low-level jets, drylines, elevated mixed layers, and extratropical cyclones--that link the large-scale climate to SLS environments. This work analyzes spatiotemporal distributions of both the environmental parameters and synoptic-scale features in ERA5 reanalysis and in Community Atmosphere Model version 6 (CAM6) during 1980--2014 over North America. Compared to radiosondes, ERA5 successfully reproduces SLS environments, with strong spatiotemporal correlations and low biases, especially over the Great Plains. Both ERA5 and CAM6 reproduce the climatology of SLS environments over the central United States as well as its strong seasonal and diurnal cycles. ERA5 and CAM6 also reproduce the climatological occurrence of the synoptic-scale features, with the distribution pattern similar to that of SLS environments. Compared to ERA5, CAM6 exhibits a high bias in Convective Available Potential Energy over the eastern United States primarily due to a high bias in surface moisture, and to a lesser extent, storm-relative helicity due to enhanced low-level winds. Composite analysis indicates consistent synoptic anomaly patterns favorable for significant SLS environments over much of the eastern half of the United States in both ERA5 and CAM6, though the pattern differs for the southeastern United States. Overall, results indicate that both ERA5 and CAM6 are capable of reproducing SLS environments as well as the synoptic-scale features and transient events that generate them.
CO2 Laser Surgery of the Upper Airway

The use of CO2 laser surgery in otolaryngology has served as an effective tool to treat various lesions in the upper airway. This article discusses the application of the CO2 laser to the upper airway, with specific reference to the larynx, nasal cavity, nasopharynx, and oropharynx.
The Department of Justice as a gatekeeper in whistleblower-initiated corporate fraud enforcement: Drivers and consequences

Abstract We examine drivers and consequences of U.S. Department of Justice (DOJ) oversight of whistleblower cases of corporate fraud against the government. We find that the DOJ is more likely to intervene in and conduct longer investigations of cases that have a higher chance of victory and yield greater monetary proceeds, indicating that DOJ enforcement is influenced by its performance measures. DOJ intervention also affects the firm- and aggregate-level fraud environment. Firms subject to DOJ intervention improve their employee relations, internal controls, and board independence, and experience lower future whistleblowing risk. Whistleblowers avoid courts and agencies with low DOJ intervention rates. In contrast, we do not find that cases pursued by whistleblowers alone affect firms' or whistleblowers' behavior, suggesting that public enforcement through DOJ intervention has a greater deterrent effect on fraud than private enforcement by whistleblowers acting alone.
On the Complexity of BWT-Runs Minimization via Alphabet Reordering

The Burrows-Wheeler Transform (BWT) has been an essential tool in text compression and indexing. First introduced in 1994, it went on to provide the backbone for the first encoding of the classic suffix tree data structure in space close to entropy-based lower bound. Within the last decade, it has seen its role further enhanced with the development of compact suffix trees in space proportional to "r", the number of runs in the BWT. While r would superficially appear to be only a measure of space complexity, it is actually appearing increasingly often in the time complexity of new algorithms as well. This makes having the smallest value of r of growing importance. Interestingly, unlike other popular measures of compression, the parameter r is sensitive to the lexicographic ordering given to the text’s alphabet. Despite several past attempts to exploit this fact, a provably efficient algorithm for finding, or approximating, an alphabet ordering which minimizes r has been open for years. We help to explain this lack of progress by presenting the first set of results on the computational complexity of minimizing BWT-runs via alphabet reordering. We prove that the decision version of this problem is NP-complete and cannot be solved in time poly(n)⋅ 2^o(σ) unless the Exponential Time Hypothesis fails, where σ is the size of the alphabet and n is the length of the text. Moreover, we show that the optimization variant is APX-hard. In doing so, we relate two previously disparate topics: the optimal traveling salesperson path of a graph and the number of runs in the BWT of a text. In addition, by relating recent results in the field of dictionary compression, we illustrate that an arbitrary alphabet ordering provides an O(log² n)-approximation. Lastly, we provide an optimal linear-time algorithm for a more restricted problem of finding an optimal ordering on a subset of symbols (occurring only once) under ordering constraints.
MDEA: Malware Detection with Evolutionary Adversarial Learning

Malware detection have used machine learning to detect malware in programs. These applications take in raw or processed binary data to neural network models to classify as benign or malicious files. Even though this approach has proven effective against dynamic changes, such as encrypting, obfuscating and packing techniques, it is vulnerable to specific evasion attacks where that small changes in the input data cause misclassification at test time. This paper proposes a new approach: MDEA, an Adversarial Malware Detection model uses evolutionary optimization to create attack samples to make the network robust against evasion attacks. By retraining the model with the evolved malware samples, its performance improves a significant margin.
Low-Loss, High-Bandwidth Fiber-to-Chip Coupling using Capped Adiabatic Tapered Fibers

We demonstrate adiabatically tapered fibers clad with a higher-index material for coupling to an on-chip waveguide. The loss from fiber to a sub-micron waveguide in a packaged device is 1.3 dB, and the 3 dB bandwidth is is 90 nm.
Divergent impact of grazing on plant communities of created wetlands with varying hydrology and antecedent land use

Destruction of natural wetlands has warranted the creation of wetlands to mitigate the reduction of valuable ecosystem functions and services. However, the complex interactions among key drivers of wetland community structure–hydrology, nutrient availability and herbivory-makes creation of functional wetland replacements challenging. We examined interactions among these drivers, and their impacts on plant communities and soil characteristics in two created wetlands with different hydrology and land use histories: a shallow emergent marsh on a previous gravel depository and a seasonally flooded marsh on a former cattle pasture. In paired plots open to or protected from large wetland grazers we observed seasonal variation in grazing impacts on plant communities and an increase in effect size over time. At the permanently flooded marsh with high waterfowl densities and low nutrients, open plots had significantly reduced plant growth and diversity, and an increase in submerged vegetation. In contrast, grazer density was lower and nutrients were higher in the seasonally flooded marsh, where grazer access enhanced plant diversity and reduced invasive plant cover. These results suggest the possibility of long-term grazer-induced shifts in community composition and delivery of key ecosystem services in young, vulnerable created wetlands. To improve created wetland design and function, we suggest that in addition to hydrologic conditions, the impact of prior land use on present nutrient availability be considered. Further, enhanced heterogeneity of spatial and bathymetric structure can provide conditions for diverse plant communities and balanced habitat use by wetland grazers.
Reconstructing the Position and Intensity of Multiple Gamma-Ray Point Sources With a Sparse Parametric Algorithm

We present an experimental demonstration of additive point source localization (APSL), a sparse parametric imaging algorithm that reconstructs the 3-D positions and activities of multiple gamma-ray point sources. Using a handheld gamma-ray detector array and up to four 8 $\mu $ Ci 137Cs gamma-ray sources, we performed both source-search and source-separation experiments in an indoor laboratory environment. In the majority of the source-search measurements, APSL reconstructed the correct number of sources with position accuracies of ~20 cm and activity accuracies (unsigned) of ~20%, given measurement times of 2 to 3 min and distances of closest approach (to any source) of ~20 cm. In source-separation measurements where the detector could be moved freely about the environment, APSL was able to resolve two sources separated by 75 cm or more given only ~60 s of measurement time. In these source-separation measurements, APSL produced larger total activity errors of ~40%, but obtained source-separation distances accurate to within 15 cm. We also compare our APSL results against traditional maximum likelihood-expectation maximization (ML-EM) reconstructions and demonstrate improved image accuracy and interpretability using APSL over ML-EM. These results indicate that APSL is capable of accurately reconstructing gamma-ray source positions and activities using measurements from existing detector hardware.
Cox Models for Vehicular Networks: SIR Performance and Equivalence

We introduce a general framework for the modeling and analysis of vehicular networks by defining street systems as random 1D subsets of $\mathbb {R}^{2}$ . The street system, in turn, specifies the random intensity measure of a Cox process of vehicles, i.e., vehicles form independent 1D Poisson point processes on each street. Models in this Coxian framework can characterize streets of different lengths and orientations forming intersections or T-junctions. The lengths of the streets can be infinite or finite and mutually independent or dependent. We analyze the reliability of communication for different models, where reliability is the probability that a vehicle at an intersection, a T-junction, or a general location can receive a message successfully from a transmitter at a certain distance. Further, we introduce a notion of equivalence between vehicular models, which means that a representative model can be used as a proxy for other models in terms of reliability. Specifically, we prove that the Poisson stick process-based vehicular network is equivalent to the Poisson line process-based and Poisson lilypond model-based vehicular networks, and their rotational variants.
CENTRAL SEQUENCES IN SUBHOMOGENEOUS UNITAL C*-ALGEBRAS

Suppose that is a unital subhomogeneous C*-algebra. We show that every central sequence in is hypercentral if and only if every pointwise limit of a sequence of irreducible representations is multiplicity free. We also show that every central sequence in is trivial if and only if every pointwise limit of irreducible representations is irreducible. Finally, we give a nice representation of the latter algebras.
Scattering from layered seafloors: Comparisons between theory and integral equations

Acoustic scattering from layered seafloors exhibits dependence on both the mean geoacoustic layering, as well as the roughness properties of each layer. Several theoretical treatments of this environment exist, including the small roughness perturbation approximation, the Kirchhoff approximation, and three different versions of the small slope approximation. All of these models give different results for the scattering cross section and coherent reflection coefficient, and there is currently no way to distinguish which model is the most correct. In this work, an integral equation for scattering from a layered seafloor with rough interfaces is presented, and compared with small roughness perturbation method, and two of the small slope approximations. It is found that the most recent small slope approximation by Jackson and Olson [J. Acoust. Soc. Am. 147(1), 56–73 (2020)] is the most accurate when the root-mean-square (rms) roughness is large, and some models are in close agreement with each other when the rms roughness is small.
Improved autonomous error correction using variable dissipation in small logical qubit architectures

Coherence times for superconducting qubits have greatly improved over time. Moreover, small logical qubit architectures using engineered dissipation have shown great promise for further improvements in the coherence of a logical qubit manifold comprised of few physical qubits. Nevertheless, optimal working parameters for small logical qubits are generally not well understood. This work presents several approaches to finding preferential parameter configurations by looking at three different cases of increasing complexity. We begin by looking at state stabilization of a single qubit using dissipation via coupling to a lossy object. We look at the limiting factors in this approach to error correction, and how we address those by numerically optimizing the parametric coupling strength with the lossy object having an effective time-varying dissipation rate---we call this a pulse-reset cycle. We then translate this approach to more efficient state stabilization to an abstracted three-qubit flip code, and end by looking at the Very Small Logical Qubit (VSLQ). By using these techniques, we can further increase logical state lifetimes for different architectures. We show significant advantages in using a pulse-reset cycle over numerically optimized, fixed parameter spaces.
Parseval’s identity and optimal transport maps

Abstract Recent findings for optimal transport maps between distribution functions sharing the same copula show that componentwise the solution is the optimal map between the marginal distributions. This is an important discovery since in the multivariate setting optimal maps are difficult to find and only known in a few special cases. In this paper, we extend the result on common copulas by showing that orthonormal transformations of variables sharing a common copula also have a known optimal map. We illustrate this by establishing optimal maps between members of a class of scale mixture of normal distributions.
Simulating 0+1 Dimensional Quantum Gravity on Quantum Computers: Mini-Superspace Quantum Cosmology and the World Line Approach in Quantum Field Theory

Quantum computers are promising candidates to radically expand the domain of computational science by their increased computing power and more effective algorithms. In particular, quantum computing could have a tremendous impact on the field of quantum cosmology. The goal of quantum cosmology is to describe the evolution of the universe through the Wheeler-DeWitt equation or path integral methods without having to first formulate a full theory of quantum gravity. The quantum computer provides an advantage in this endeavor because it can perform path integrals directly in Lorentzian space and does not require constructing contour integrations in Euclidean gravity. Also, quantum computers can provide advantages in systems with fermions which are difficult to simulate on classical computers. In this study, we first employed classical computational methods to analyze a Friedmann-Robertson-Walker mini-superspace with a scalar field and visualize the calculated wavefunction of the universe for a variety of different values of the curvature of the universe and the cosmological constant. We then used IBM’s Quantum Information Science Kit Python library and the variational quantum eigensolver algorithm to study the same systems on a quantum computer. The framework was extended to the world line approach to quantum field theory.
B Physics on the Lattice:. Present and Future

Recent experimental measurements and lattice QCD calculations are now reaching the precision (and accuracy) needed to over-constrain the CKM parameters and . In this brief review, we discuss the current status of lattice QCD calculations needed to connect the experimental measurements of B meson properties to quark flavor-changing parameters. Special attention is given to B→πlν, which is becoming a competitive way to determine |Vub|, and to mixings, which now include reliable extrapolation to the physical light quark mass. The combination of the recent measurement of the Bs mass difference and current lattice calculations dramatically reduces the uncertainty in |Vtd|. We present an outlook for reducing dominant lattice QCD uncertainties entering CKM fits and remark on lattice calculations for other decay channels.
Probing Early Structure Formation with Far-Infrared Background Correlations

The large-scale structure of high-redshift galaxies produces correlated anisotropy in the far-infrared background (FIRB). In regions of the sky where the thermal emission from Galactic dust is well below average, these high-redshift correlations may be the most significant source of angular fluctuation power over a wide range of angular scales, from ~7' to ~3°, and frequencies, from ~400 to ~1000 GHz. The strength of this signal should allow detailed studies of the statistics of the FIRB fluctuations, including the shape of the angular power spectrum at a given frequency and the degree of coherence between FIRB maps at different frequencies. The FIRB correlations depend on and hence constrain the redshift-dependent spectral energy distributions, number counts, and clustering bias of the galaxies and active nuclei that contribute to the background. We quantify the accuracy to which Planck and a newly proposed balloon-borne mission, Explorer of Diffuse Galactic Emissions, could constrain models of the high-redshift universe through the measurement of FIRB fluctuations. We conclude that the average bias of high-redshift galaxies could be measured to an accuracy of 1% or, for example, separated into four redshift bins with ~10% accuracy.
A second look at string-inspired models for proton-proton scattering via Pomeron exchange

We re-examine a string dual model for elastic proton-proton scattering via Pomeron exchange. We argue that the method of “Reggeizing” a propagator to take into account an entire trajectory of exchanged particles can be generalized, in particular by modifying the value of a mass-shell parameter in the model. We then fit the generalized model to scattering data at large s and small t. The fitting results are inconclusive, but suggest that a better fit might be obtained by allowing the mass-shell parameter to vary. The model fits the data equally well (roughly) for a wide range of values of the mass-shell parameter, but the other fitting parameters (the slope and intercept of the Regge trajectory, and the coupling constant and dipole mass from the proton-proton-glueball coupling) are then inconsistent with what we expect. On the other hand, using the traditional method of Reggeization generates a weaker fit, but the other parameters obtain more physically reasonable values. In analyzing the fitting results, we also found that our model is more consistent with the $$ \sqrt{s}=1800 $$ GeV data coming from the E710 experiment than that coming from the CDF experiment, and that our model has the greatest discrepancy with the data in the range 0.5 GeV2 < |t| < 0.6 GeV2, suggesting that the transition from soft Pomeron to hard Pomeron may occur closer to t = −0.5 GeV2 rather than t = −0.6 GeV2 as previously thought.
Dark Matter Distribution of Four Low-z Clusters of Galaxies

We present here the weak gravitational lensing detection of four nearby galaxy clusters in the southern sky: Abell 2029, Abell 85, Abell 1606 and Abell 2457. The weak lensing detections of Abell 1606 and Abell 2457 are the first in the literature. This work capitalizes on the wide field of view of the Dark Energy Camera at the Cerro Tololo Inter-American Observatory, which we use to obtain deep, multi-wavelength imaging of all targets. We publish maps of the clusters' projected mass distributions, and obtain the $M_{200}$ of their clusters through NFW profile fits to the two-dimensional tangential ellipticity signal.
From Solar and Stellar Flares to Coronal Heating: Theory and Observations of How Magnetic Reconnection Regulates Coronal Conditions

There is currently no explanation of why the corona has the temperature and density it has. We present a model that explains how the dynamics of magnetic reconnection regulates the conditions in the corona. A bifurcation in magnetic reconnection at a critical state enforces an upper bound on the coronal temperature for a given density. We present observational evidence from 107 flares in 37 Sun-like stars that stellar coronae are near this critical state. The model may be important to self-organized criticality models of the solar corona.
Extra)ordinary gauge mediation

We study models of ``(extra)ordinary gauge mediation, which consist of taking ordinary gauge mediation and extending the messenger superpotential to include all renormalizable couplings consistent with SM gauge invariance and an R-symmetry. We classify all such models and find that their phenomenology can differ significantly from that of ordinary gauge mediation. Some highlights include: arbitrary modifications of the squark/slepton mass relations, small μ and Higgsino NLSP's, and the possibility of having fewer than one effective messenger. We also show how these models lead naturally to extremely simple examples of direct gauge mediation, where SUSY and R-symmetry breaking occur not in a hidden sector, but due to the dynamics of the messenger sector itself.
An analytic model of plasma-neutral coupling in the heliosphere plasma

We have developed an analytic model to describe coupling of plasma and neutral fluids in the partially ionized heliosphere plasma medium. The sources employed in our analytic model are based on a κ-distribution as opposed to the Maxwellian distribution function. Our model uses the κ-distribution to analytically model the energetic neutral atoms that result in the heliosphere partially ionized plasma from charge exchange with the protons and subsequently produce a long tail, which is otherwise not describable by the Maxwellian distribution. We present our analytic formulation and describe major differences in the sources emerging from these two distinct distributions.
Slender origami with complex 3D folding shapes

One-dimensional slender bodies can be deformed or shaped into spatially complex curves relatively easily due to their inherent compliance. However, traditional methods of fabricating complex spatial shapes are cumbersome, prone to error accumulation and not amenable to elegant programmability. In this letter, we introduce a one-dimensional origami based on attaching Miura-ori that can fold into various programmed two- or three-dimensional shapes. We study the out-of-plane displacement characteristics of this origami and demonstrate with examples, design of slender bodies that conform to programmed complex spatial curves. Our study provides a new, accurate, and single actuation solution of shape programmability.
Recruiting experimental subjects using WhatsApp

Abstract The aim of many experiments is to estimate the effect of different interventions on subjects’ decision making. However, obtaining large samples and internal validity is challenging. This paper presents an alternative device at almost no cost that can easily provide a very large number of participants (700 in 1 hour). We asked 14 students to invite their WhatsApp contacts to participate in an online experiment. The students created a total of 80 diffusion groups with 25 contacts each. Using the diffusion groups as clusters, we ran a cluster randomization procedure in order to assign subjects to a framing experiment (treatment + control). We obtained the same level of attrition, duplicates and uninvited subjects across the treatment and control groups. Moreover, the experiment yielded consistent results in line with the framing literature.
Munchausen Reinforcement Learning

Bootstrapping is a core mechanism in Reinforcement Learning (RL). Most algorithms, based on temporal differences, replace the true value of a transiting state by their current estimate of this value. Yet, another estimate could be leveraged to bootstrap RL: the current policy. Our core contribution stands in a very simple idea: adding the scaled log-policy to the immediate reward. We show that slightly modifying Deep Q-Network (DQN) in that way provides an agent that is competitive with distributional methods on Atari games, without making use of distributional RL, n-step returns or prioritized replay. To demonstrate the versatility of this idea, we also use it together with an Implicit Quantile Network (IQN). The resulting agent outperforms Rainbow on Atari, installing a new State of the Art with very little modifications to the original algorithm. To add to this empirical study, we provide strong theoretical insights on what happens under the hood -- implicit Kullback-Leibler regularization and increase of the action-gap.
Higher-order spin noise statistics

The optical spin noise spectroscopy (SNS) is a minimally invasive route toward obtaining dynamical information about electrons and atomic gases by measuring mesoscopic time-dependent spin fluctuations. Recent improvements of the sensitivity of SNS should make it possible to observe higher-order spin correlators at thermodynamic equilibrium. We develop theoretical methods to explore higher-order (third and fourth) cumulants of the spin noise in the frequency domain. We make predictions for the possible functional form of these correlators in single quantum dot experiments and then apply the method of the stochastic path integral to estimate the effects of many-body interactions.
Asymptotics for the wave equation on differential forms on Kerr–de Sitter space

We study asymptotics for solutions of Maxwell’s equations, in fact, of the Hodge–de Rham equation $(d+\delta)u = 0$ without restriction on the form degree, on a geometric class of stationary spacetimes with a warped product type structure (without any symmetry assumptions), which, in particular, include Schwarzschild—de Sitter spaces of all spacetime dimensions $n \geq 4$. We prove that solutions decay exponentially to $0$ or to stationary states in every form degree, and give an interpretation of the stationary states in terms of cohomological information of the spacetime. We also study the wave equation on differential forms and, in particular, prove analogous results on Schwarzschild–de Sitter spacetimes. We demonstrate the stability of our analysis and deduce asymptotics and decay for solutions of Maxwell’s equations, the Hodge–de Rham equation and the wave equation on differential forms on Kerr–de Sitter spacetimes with small angular momentum.
Learning the Image Processing Pipeline

Many creative ideas are being proposed for image sensor designs, and these may be useful in applications ranging from consumer photography to computer vision. To understand and evaluate each new design, we must create a corresponding image processing pipeline that transforms the sensor data into a form, that is appropriate for the application. The need to design and optimize these pipelines is time-consuming and costly. We explain a method that combines machine learning and image systems simulation that automates the pipeline design. The approach is based on a new way of thinking of the image processing pipeline as a large collection of local linear filters. We illustrate how the method has been used to design pipelines for novel sensor architectures in consumer photography applications.
Kinetic heterogeneities at dynamical crossovers

We perform molecular dynamics simulations of a model glass-forming liquid to measure the size of kinetic heterogeneities, using a dynamic susceptibility χss(a, t) that quantifies the number of particles whose dynamics are correlated on the length scale a and time scale t. By measuring χss(a, t) as a function of both a and t, we locate local maxima χ at distances a and times t. Near the dynamical glass transition, we find two types of maxima, both correlated with crossovers in the dynamical behavior: a smaller maximum corresponding to the crossover from ballistic to sub-diffusive motion, and a larger maximum corresponding to the crossover from sub-diffusive to diffusive motion. Our results indicate that kinetic heterogeneities are not necessarily signatures of an impending glass or jamming transition.
HIGH-RESOLUTION XMM-NEWTON SPECTROSCOPY OF THE COOLING FLOW CLUSTER A3112

We examine high signal-to-noise XMM-Newton European Photon Imaging Camera (EPIC) and Reflection Grating Spectrometer (RGS) observations to determine the physical characteristics of the gas in the cool core and outskirts of the nearby rich cluster A3112. The XMM-Newton Extended Source Analysis Software data reduction and background modeling methods were used to analyze the XMM-Newton EPIC data. From the EPIC data, we find that the iron and silicon abundance gradients show significant increase toward the center of the cluster while the oxygen abundance profile is centrally peaked but has a shallower distribution than that of iron. The X-ray mass modeling is based on the temperature and deprojected density distributions of the intracluster medium determined from EPIC observations. The total mass of A3112 obeys the M-T scaling relations found using XMM-Newton and Chandra observations of massive clusters at r{sub 500}. The gas mass fraction f{sub gas} = 0.149{sup +0.036}{sub -0.032} at r{sub 500} is consistent with the seven-year Wilkinson Microwave Anisotropy Probe results. The comparisons of line fluxes and flux limits on the Fe XVII and Fe XVIII lines obtained from high-resolution RGS spectra indicate that there is no spectral evidence for cooler gas associated with the cluster with temperature below 1.0more » keV in the central <38'' ({approx}52 kpc) region of A3112. High-resolution RGS spectra also yield an upper limit to the turbulent motions in the compact core of A3112 (206 km s{sup -1}). We find that the contribution of turbulence to total energy is less than 6%. This upper limit is consistent with the energy contribution measured in recent high-resolution simulations of relaxed galaxy clusters.« less
Congruences for Fishburn numbers modulo prime powers

The Fishburn numbers ξ(n) are defined by the formal power series Recently, Andrews and Sellers discovered congruences of the form ξ(pm + j) ≡ 0 modulo p, valid for all m ≥ 0. These congruences have then been complemented and generalized to the case of r-Fishburn numbers by Garvan. In this note, we answer a question of Andrews and Sellers regarding an extension of these congruences to the case of prime powers. We show that, under a certain condition, all these congruences indeed extend to hold modulo prime powers.
Crystal structure of a guanine nucleotide exchange factor encoded by the scrub typhus pathogen Orientia tsutsugamushi

Rho family GTPases regulate an array of cellular processes and are often modulated by pathogens to promote infection. Here, we identify a cryptic guanine nucleotide exchange factor (GEF) domain in the OtDUB protein encoded by the pathogenic bacterium Orientia tsutsugamushi A proteomics-based OtDUB interaction screen identified numerous potential host interactors, including the Rho GTPases Rac1 and Cdc42. We discovered a domain in OtDUB with Rac1/Cdc42 GEF activity (OtDUBGEF), with higher activity toward Rac1 in vitro. While this GEF bears no obvious sequence similarity to known GEFs, crystal structures of OtDUBGEF alone (3.0 A) and complexed with Rac1 (1.7 A) reveal striking convergent evolution, with a unique topology, on a V-shaped bacterial GEF fold shared with other bacterial GEF domains. Structure-guided mutational analyses identified residues critical for activity and a mechanism for nucleotide displacement. Ectopic expression of OtDUB activates Rac1 preferentially in cells, and expression of the OtDUBGEF alone alters cell morphology. Cumulatively, this work reveals a bacterial GEF within the multifunctional OtDUB that co-opts host Rac1 signaling to induce changes in cytoskeletal structure.
EXTERNAL COMPTON SCATTERING IN BLAZAR JETS AND THE LOCATION OF THE GAMMA-RAY EMITTING REGION

I study the location of the $\gamma$-ray emission in blazar jets by creating a Compton-scattering approximation valid for all anisotropic radiation fields in the Thomson through Klein-Nishina regimes, which is highly accurate and can speed up numerical calculations by up to a factor $\sim10$. I apply this approximation to synchrotron self-Compton, and external Compton-scattering of photons from the accretion disk, broad-line region (BLR), and dust torus. I use a stratified BLR model and include detailed Compton-scattering calculations of a spherical and flattened BLR. I create two dust torus models, one where the torus is an annulus, and one where it is an extended disk. I present detailed calculations of the photoabsorption optical depth using my detailed BLR and dust torus models, including the full angle dependence. I apply these calculations to the emission from a relativistically moving blob traveling through these radiation fields. The ratio of $\gamma$-ray to optical flux produces a predictable pattern that could help locate the $\gamma$-ray emission region. I show that the bright flare from 3C 454.3 in 2010 November detected by the Fermi Large Area Telescope is unlikely to originate from a single blob inside the BLR since it moves outside the BLR in a time shorter than the flare duration, although emission by multiple blobs inside the BLR is possible; and $\gamma$-rays are unlikely to originate from outside the BLR from scattering of photons from an extended dust torus, since then the cooling timescale would be too long to explain the observed short variability.
Graphene Induced Surface Reconstruction of Cu

An atomic-scale study utilizing scanning tunneling microscopy (STM) in ultrahigh vacuum (UHV) is performed on large single crystalline graphene grains synthesized on Cu foil by a chemical vapor deposition (CVD) method. After thermal annealing, we observe the presence of periodic surface depressions (stripe patterns) that exhibit long-range order formed in the area of Cu covered by graphene. We suggest that the observed stripe pattern is a Cu surface reconstruction formed by partial dislocations (which appeared to be stair-rod-like) resulting from the strain induced by the graphene overlayer. In addition, these graphene grains are shown to be more decoupled from the Cu substrate compared to previously studied grains that exhibited Moire patterns.
Rhombic tilings and Bott–Samelson varieties

S.~Elnitsky (1997) gave an elegant bijection between rhombic tilings of $2n$-gons and commutation classes of reduced words in the symmetric group on $n$ letters. P.~Magyar (1998) found an important construction of the Bott-Samelson varieties introduced by H.C.~Hansen (1973) and M.~Demazure (1974). We explain a natural connection between S.~Elnitsky's and P.~Magyar's results. This suggests using tilings to encapsulate Bott-Samelson data (in type $A$). It also indicates a geometric perspective on S.~Elnitsky's combinatorics. We also extend this construction by assigning desingularizations to the zonotopal tilings considered by B.~Tenner (2006).
On the Mass and Metallicity Distributions of the Parent AGB Stars of O-Rich Presolar Stardust Grains

Presolar grains in meteorites formed in a sample of Asymptotic Giant Branch (AGB) stars that ended their lives within ≈1 Gyr of the origin of the Solar System 4.6 Gyr ago. The O-isotopic compositions of presolar O-rich stardust reflect the masses and metallicities of their parent stars. We present simple Monte Carlo simulations of the parent AGB stars of presolar grains. Comparison of model predictions with the grain data allow some broad conclusions to be drawn: (1) Presolar O-rich grains formed in AGB stars of mass ~1.15–2.2 M⊙. The upper-mass cutoff reflects dredge-up of C in more massive AGB stars, leading to C-rich dust rather than O-rich, but the lack of grains from intermediate-mass AGB stars (>4 M⊙) is a major puzzle; (2) The grain O-isotopic data are reproduced well if the Galaxy in presolar times was assumed to have a moderate age-metallicity relationship, but with significant metallicity scatter for stars born at the same time; (3) The Sun appears to have a moderately low metallicity for its age and/or unusual 17O/16O and 18O/16O ratios for its metallicity; and (4) The Solar 17O/18O ratio, while unusual relative to present-day molecular clouds and protostars, was not atypical for the presolar disk and does not require self-pollution of the protosolar molecular cloud by supernova ejecta.
The local-field factor and microscopic cascading: a self-consistent method applied to confined systems of molecules

We use a simplified self-consistent method to address nonlinear-optical cascading phenomena, which shows added microscopic cascading contributions in high-ordered nonlinear susceptibilities through fifth order. These cascading terms in the microscopic regime encompass all possible scalar cascading configurations. The imposition of geometric constraints further influences the predicted cascading contributions and opens up additional design parameters for nonlinear-optical materials. These results are used in approximating the effective fifth-order susceptibility in thin films of C60 monomers of varying thickness and concentration.
Quantum Suppression of Alignment in Ultrasmall Grains: Microwave Emission from Spinning Dust will be Negligibly Polarized

The quantization of energy levels in very nanoparticles suppresses dissipative processes that convert grain rotational kinetic energy into heat. For grains small enough to have GHz rotation rates, the suppression of dissipation can be extreme. As a result, alignment of such grains is suppressed. This applies both to alignment of the grain body with its angular momentum J, and to alignment of J with the local magnetic field B_0. If the anomalous microwave emission is rotational emission from spinning grains, it will be negligibly polarized at GHz frequencies, with P < 10^{-6} at frequencies above 10 GHz.
Newtonian valued differential fields with arbitrary value group

The notion of newtonianity is central to the study of the ordered differential field of logarithmic-exponential transseries done by Aschenbrenner, van den Dries, and van der Hoeven; see [Asymptotic...
Satellites of Radio AGN in SDSS: Insights into AGN Triggering and Feedback

We study the effects of radio jets on galaxies in their vicinity (satellites) and the role of satellites in triggering radio-loud active galactic nuclei (AGNs). The study compares the aggregate properties of satellites of a sample of 7220 radio AGNs at z < 0.3 (identified by Best and Heckman from the SDSS and NVSS+FIRST surveys) to the satellites of a control sample of radio-quiet galaxies, which are matched in redshift, color, luminosity, and axis ratio, as well as by environment type: field galaxies, cluster members, and brightest cluster galaxies (BCGs). Remarkably, we find that radio AGNs exhibit on average a 50% excess (17σ significance) in the number of satellites within 100 kpc even though the cluster membership was controlled (e.g., radio BCGs have more satellites than radio-quiet BCGs, etc.). Satellite excess is not confirmed for high-excitation sources, which are only 2% of radio AGN. Extra satellites may be responsible for raising the probability for hot gas AGN accretion via tidal effects or may otherwise enhance the intensity or duration of the radio-emitting phase. Furthermore, we find that the incidence of radio AGNs among potential hosts (massive ellipticals) is similar for field galaxies and for non-BCG cluster members, suggesting that AGNmore » fueling depends primarily on conditions in the host halo rather than the parent, cluster halo. Regarding feedback, we find that radio AGNs, either high or low excitation, have no detectable effect on star formation in their satellites, as neither induced star formation nor star formation quenching is present in more than ∼1% of radio AGN.« less
A Flaring AGN in a ULIRG Candidate in Stripe 82

We report the discovery of a mid-infrared variable AGN that is hosted by an ultraluminous infrared galaxy (ULIRG) in the Sloan Stripe 82 field. WISE J030654.88+010833.6 is a red, extended galaxy, which we estimate to be at a photometric redshift of 0.28 ≤ z ≤ 0.31, based on its optical and near-infrared spectral energy distribution (SED). The factor of two variability over 8 yr seen in the Wide-field Infrared Survey Explorer (WISE) 3.4 and 4.6 μm wavelength channels is not clearly correlated with optical variability in archival data. Based on our estimation of the physical parameters of the host galaxy, J030654.88+010833.6 is possibly a composite AGN/starburst ULIRG in a phase where high star formation ~70 M_⊙ yr^(−1) is occurring. Our estimate of the black hole mass to stellar mass ratio also appears to be consistent with that of broad line AGN in the local universe. The long-term variability of J030654.88+010833.6 as seen in the WISE W1 and W2 light curves is likely due to variations in the accretion rate, with the energy being reprocessed by dust in the vicinity of the AGN.
Energy-Efficient Joint User-RB Association and Power Allocation for Uplink Hybrid NOMA-OMA

In this paper, energy efficient resource allocation is considered for an uplink hybrid system, where non-orthogonal multiple access is integrated into orthogonal multiple access (OMA). To ensure the quality of service for the users, a minimum rate requirement is predefined for each user. An energy efficiency (EE) maximization problem is formulated by jointly optimizing the user clustering, channel assignment, and power allocation (PA). To address this problem, a many-to-one bipartite graph is first constructed considering the users and resource blocks (RBs) as the two sets of nodes. Based on swap matching, a joint user-RB association and PA scheme is proposed, which converges within a limited number of iterations. Moreover, for the PA under a given user-RB association, a feasibility condition is first derived. If feasible, a low-complexity algorithm is proposed, which obtains optimal EE for any successive interference cancellation (SIC) order and an arbitrary number of users. In addition, for the special case of two users per cluster, analytical solutions are provided for the two orders in which SIC can be implemented. These solutions shed light on how the power is allocated for each user to maximize the EE. Numerical results are presented, which show that the proposed joint user-RB association and PA algorithm outperforms other hybrid multiple-access-based and OMA-based schemes.