cssi/SciSciGPT-SciSciNet huggingface dataset:
Chapter 9 - Electromagnetic migration

The conventional approach to interpretation of the observed electromagnetic data based on standard 3-D forward modeling and inversion meets significant difficulties because of the enormous amount of computations required in the case of the multitransmitter and multireceiver data acquisition systems typical for modern EM geophysical surveys. There exists, however, an alternative approach to the solution of this problem, called EM migration, based on the principles of EM holography, which extends to EM cases the methods of optical and radio holography. Electromagnetic migration is based on a special form of downward continuation of the observed field or one of its components. This downward continuation is obtained as the solution of the boundary value problem in the lower half-space for the adjoint Maxwell's equations, in which the boundary values of the migration field on the earth's surface are determined by the observed electromagnetic field data. Chapter 9 presents an overview of the principles of EM migration in the time and frequency domains. We also discuss the numerical methods of migration including the methods based on integral transformation, digital filters, and finite difference approach. The final section of this chapter presents an iterative migration, which is similar to the conventional iterative inversion, discussed in Chapter 8.
Green-to-Blue Triplet Fusion Upconversion Sensitized by Anisotropic CdSe Nanoplatelets

Green-to-blue photon upconversion bears great potential in photocatalytic applications. Current hybrid inorganic–organic upconversion schemes commonly utilize spherical CdSe nanocrystals, but size ...
Does Transparency Reduce Favoritism and Corruption? Evidence From the Reform of Figure Skating Judging

Transparency is usually thought to reduce favoritism and corruption by facilitating monitoring by outsiders, but there is concern it can have the perverse effect of facilitating collusion by insiders. In response to vote trading scandals in the 1998 and 2002 Olympics, the International Skating Union (ISU) introduced a number of changes to its judging system, including obscuring which judge issued which mark. The stated intent was to disrupt collusion by groups of judges, but this change also frustrates most attempts by outsiders to monitor judge behavior. The author finds that the “compatriot-judge effect,” which aggregates favoritism (nationalistic bias from own-country judges) and corruption (vote trading), actually increased slightly after the reforms.
Chapter 1 – Cells and Diffusion

Publisher Summary This chapters begins by outlining the structures of certain plant cells and tissues; however, it mainly concerns diffusion. The living material of a cell, known as the protoplast, is surrounded by the cell wall. The cell wall is composed of cellulose and other polysaccharides, which helps provide rigidity to individual cells as well as to the whole plant. Explaining the structure, the chapter delves into root anatomy and leaf anatomy. Further, it discusses the diffusion, which leads to the net movement of a substance from a region of higher concentration to an adjacent region of lower concentration of that substance. Diffusion takes place in both the liquid and the gas phases associated with plants and is a result of the random thermal motion of the molecules—the solute(s) and the solvent in the case of a solution or of gases in the case of air. The net movement caused by diffusion is a statistical phenomenon—a greater probability exists for molecules to move from the concentrated region to the dilute region than vice versa. Diffusion is involved in many plant processes, such as gas exchange and the movement of nutrients toward root surfaces.
Estimation of Mortality Rates From Insurance Data

The problem of using insurance intercompany data to determine mortality rates has had a long history of development. The development of these mortality rates involves two steps, namely, the estimation of the rates from the data and the interpolation and smoothing of these rates to conform to known trends in the mortality rates by age, and time since first insured. This paper will discuss the different methods used to determine these rates and discuss the advantages and disadvantages of each approach. Keywords: mortality; estimation; smoothing; select mortality; ultimate mortality
On a novel approach for modeling liquid crystalline flows

In this paper, we derive a new model for the description of liquid crystalline flows. While microscopic Doi type models suffer from the high dimensionality of the underlying product space, the more macroscopic Ericksen--Leslie type models describe only the long time behavior of the flow and are valid only close to equilibrium. By applying an energetic variational approach, we derive a new macroscopic model which shall provide an improved description far from equilibrium. The novelty of our approach lies in the way the energy is minimized. Distinguishing between the velocities of particles and fluid allows us to define the energy dissipation not in terms of chemical potentials but in terms of friction induced by the discrepancies in the considered velocities. We conclude this publication by establishing the existence of weak solutions to the newly derived model.
A simulation-derived surrogate model for the vaporization rate of aluminum droplets heated by a passing shock wave

Abstract The vaporization rate of aluminum droplets in shocked flows plays a crucial role in determining the energy release rate during the combustion of the aluminized energetic materials. In this paper, the physics of the vaporization of aluminum droplets in shocked flows is numerically investigated. Surrogate models for the temporally averaged Sherwood number and Nusselt number, cast as functions of shock Mach number and Reynolds number, are developed from the simulation-based data. The results show that the Sherwood number and the Nusselt number of the droplet increase monotonically with the Reynolds number. On the other hand, the Sherwood number and the Nusselt number exhibit non-monotonic behavior with increasing shock Mach number due to the transition of the post-shock flow from subsonic to the supersonic speeds as the shock Mach number is increased from 1.1 to 3.5. In contrast with available models in the literature that are commonly used in process scale computations of aluminum droplet vaporization, the current models for the Sherwood number and the Nusselt number are applicable over a wide range of the Reynolds number and the Mach number and will be useful in the macro-scale multi-phase simulations of the combustion of aluminumized energetic materials in high-speed flows.
Arp2/3 and Mena/VASP Require Profilin 1 for Actin Network Assembly at the Leading Edge

Cells have many types of actin structures, which must assemble from a common monomer pool. Yet, it remains poorly understood how monomers are distributed to and shared between different filament networks. Simplified model systems suggest that monomers are limited and heterogeneous, which alters actin network assembly through biased polymerization and internetwork competition. However, less is known about how monomers influence complex actin structures, where different networks competing for monomers overlap and are functionally interdependent. One example is the leading edge of migrating cells, which contains filament networks generated by multiple assembly factors. The leading edge dynamically switches between the formation of different actin structures, such as lamellipodia or filopodia, by altering the balance of these assembly factors' activities. Here, we sought to determine how the monomer-binding protein profilin 1 (PFN1) controls the assembly and organization of actin in mammalian cells. Actin polymerization in PFN1 knockout cells was severely disrupted, particularly at the leading edge, where both Arp2/3 and Mena/VASP-based filament assembly was inhibited. Further studies showed that in the absence of PFN1, Arp2/3 no longer localizes to the leading edge and Mena/VASP is non-functional. Additionally, we discovered that discrete stages of internetwork competition and collaboration between Arp2/3 and Mena/VASP networks exist at different PFN1 concentrations. Low levels of PFN1 caused filopodia to form exclusively at the leading edge, while higher concentrations inhibited filopodia and favored lamellipodia and pre-filopodia bundles. These results demonstrate that dramatic changes to actin architecture can be made simply by modifying PFN1 availability.
A Src family kinase maintains latent sensitization in rats, a model of inflammatory and neuropathic pain

Abstract Latent sensitization is a long-term model of chronic pain in which hyperalgesia is continuously suppressed by opioid receptors, as demonstrated by the induction of mechanical allodynia by opioid antagonists. Different intracellular signals may mediate the initiation, maintenance and expression of latent sensitization. Our criterion for the involvement of a signal in the maintenance of latent sensitization is that inhibitors should permanently eliminate the allodynia produced by an opioid antagonist. We hypothesized that Src family kinases (SFKs) maintain latent sensitization and tested this hypothesis by inducing latent sensitization in rats with complete Freund’s adjuvant (CFA) or spared nerve injury. After measures of mechanical allodynia returned to baseline, vehicle or the SFK inhibitor PP2 were injected intrathecally. The opioid antagonist naltrexone injected intrathecally 15 min later produced allodynia in control rats but not in rats injected with PP2. Vehicle or PP2 were injected daily for two more days and naltrexone was injected five days later. Again, naltrexone induced allodynia in the control rats but not in the rats injected with PP2. Results were similar when latent sensitization was induced with CFA or spared nerve injury. We concluded that an SFK, likely Fyn, maintains latent sensitization induced by inflammation or nerve injury.
Limitations of Greed: Influence Maximization in Undirected Networks Re-visited

We consider the influence maximization problem (selecting k seeds in a network maximizing the expected total influence) on undirected graphs under the linear threshold model. On the one hand, we prove that the greedy algorithm always achieves a (1 - (1 - 1/k)k + Omega(1/k3))-approximation, showing that the greedy algorithm does slightly better on undirected graphs than the generic (1- (1 - 1/k)k) bound which also applies to directed graphs. On the other hand, we show that substantial improvement on this bound is impossible by presenting an example where the greedy algorithm can obtain at most a (1- (1 - 1/k)k + O(1/k0.2)) approximation. This result stands in contrast to the previous work on the independent cascade model. Like the linear threshold model, the greedy algorithm obtains a (1-(1-1/k)k)-approximation on directed graphs in the independent cascade model. However, Khanna and Lucier showed that, in undirected graphs, the greedy algorithm performs substantially better: a (1-(1-1/k)k + c) approximation for constant c > 0. Our results show that, surprisingly, no such improvement occurs in the linear threshold model. Finally, we show that, under the linear threshold model, the approximation ratio (1 - (1 - 1/k)k) is tight if 1) the graph is directed or 2) the vertices are weighted. In other words, under either of these two settings, the greedy algorithm cannot achieve (1 - (1 - 1/k)k + f(k))-approximation for any positive function f(k). The result in setting 2) is again in a sharp contrast to Khanna and Lucier's (1 - (1 - 1/k)k + c)-approximation result for the independent cascade model, where the (1 - (1 - 1/k)^k + c) approximation guarantee can be extended to the setting where vertices are weighted. We also discuss extensions to more generalized settings including those with edge-weighted graphs.
Variational Optimization on Lie Groups, with Examples of Leading (Generalized) Eigenvalue Problems

The article considers smooth optimization of functions on Lie groups. By generalizing NAG variational principle in vector space (Wibisono et al., 2016) to Lie groups, continuous Lie-NAG dynamics which are guaranteed to converge to local optimum are obtained. They correspond to momentum versions of gradient flow on Lie groups. A particular case of $\mathsf{SO}(n)$ is then studied in details, with objective functions corresponding to leading Generalized EigenValue problems: the Lie-NAG dynamics are first made explicit in coordinates, and then discretized in structure preserving fashions, resulting in optimization algorithms with faithful energy behavior (due to conformal symplecticity) and exactly remaining on the Lie group. Stochastic gradient versions are also investigated. Numerical experiments on both synthetic data and practical problem (LDA for MNIST) demonstrate the effectiveness of the proposed methods as optimization algorithms ($not$ as a classification method).
Am I a Science Person? A Strong Science Identity Bolsters Minority Students’ Sense of Belonging and Performance in College:

Identifying as a "science person" is predictive of science success, but the mechanisms involved are not well-understood. We hypothesized that science identity predicts success because it fosters a sense of belonging in science classrooms. Thus, science identity should be particularly important for first-generation and racial-minority students, who may harbor doubts about belonging in science. Two field studies in college Introductory Biology classes (Ns = 368, 639) supported these hypotheses. A strong science identity predicted higher grades, particularly for minority students. Also consistent with hypotheses, Study 2 found that self-reported belonging in college mediated the relationship between science identity and performance. Furthermore, a social belonging manipulation eliminated the relationship between science identity and performance among minority students. These results support the idea that a strong science identity is particularly beneficial for minority students because it bolsters belonging in science courses. Practical and theoretical implications are discussed.
Is Network the Bottleneck of Distributed Training

Recently there has been a surge of research on improving the communication efficiency of distributed training. However, little work has been done to systematically understand whether the network is the bottleneck and to what extent. In this paper, we take a first-principles approach to measure and analyze the network performance of distributed training. As expected, our measurement confirms that communication is the component that blocks distributed training from linear scale-out. However, contrary to the common belief, we find that the network is running at low utilization and that if the network can be fully utilized, distributed training can achieve a scaling factor of close to one. Moreover, while many recent proposals on gradient compression advocate over 100x compression ratio, we show that under full network utilization, there is no need for gradient compression in 100 Gbps network. On the other hand, a lower speed network like 10 Gbps requires only 2x-5x gradients compression ratio to achieve almost linear scale-out. Compared to application-level techniques like gradient compression, network-level optimizations do not require changes to applications and do not hurt the performance of trained models. As such, we advocate that the real challenge of distributed training is for the network community to develop high-performance network transport to fully utilize the network capacity and achieve linear scale-out.
Data-Driven Path Selection for Real-Time Video Streaming at the Network Edge.

In this paper, we present a framework for the dynamic selection of the wireless channels used to deliver information-rich data streams to edge servers. The approach we propose is data-driven, where a predictor, whose output informs the decision making of the channel selector, is built from available data on the transformation imposed by the network on previously transmitted packets. The proposed technique is contextualized to real-time video streaming for immediate processing. The core of our framework is the notion of probes, that is, short bursts of packets transmitted over unused channels to acquire information while generating a controlled impact on other active links. Results indicate a high accuracy of the prediction output and a significant improvement in terms of received video quality when the prediction output is used to dynamically select the used channel for transmission.
Mitigation of Aerosols Generated During Rhinologic Surgery: A Pandemic-Era Cadaveric Simulation.

ObjectiveAfter significant restrictions initially due to the COVID-19 pandemic, otolaryngologists have begun resuming normal clinical practice. However, the risk of SARS-CoV-2 transmission to healt...
Local Optimality of Almost Piecewise-Linear Quantizers for Witsenhausen's Problem

We pose Witsenhausen's problem as a leader–follower game of incomplete information. The follower makes a noisy observation of the leader's action (who moves first) and chooses an action minimizing her expected deviation from the leader's action. Knowing this, the leader who observes the realization of the state chooses an action that minimizes her distance to the state of the world and the ex-ante expected deviation from the follower's action. We study the perfect Bayesian equilibria of the game and identify a class of “near-piecewise-linear equilibria” when leader cares much more about being close to the follower than the state, and the state is highly volatile. As a major consequence of this result, we prove the existence of a set of local minima for Witsenhausen's problem in form of slopey quantizers, which are at most a constant factor away from the optimal cost.
Hybrid Symbolic-Numeric Framework for Power System Modeling and Analysis

With the recent proliferation of open-source packages for computing, power system differential-algebraic equation (DAE) modeling and simulation are being revisited to reduce the programming efforts. Existing open-source tools require manual efforts to develop code for numerical equations, sparse Jacobians, and discontinuous components. This paper proposes a hybrid symbolic-numeric framework, exemplified by an open-source Python-based library ANDES, which consists of a symbolic layer for descriptive modeling and a numeric layer for vector-based numerical computation. This method enables the implementation of DAE models by mixing and matching modeling components, through which models are described. In the framework, a rich set of discontinuous components and standard transfer function blocks are provided besides essential modeling elements for rapid modeling. ANDES can automatically generate robust and fast numerical simulation code, as well as and high-quality documentation. Case studies present a) two implementations of turbine governor model TGOV1, b) power flow computation time break down for MATPOWER systems, c) validation of time-domain simulation with commercial software using three test systems with a variety of models, and d) the full eigenvalue analysis for Kundur's system. Validation shows that ANDES closely matches the commercial tool DSATools for power flow, time-domain simulation, and eigenvalue analysis.
Cloud computing - the next chasm

The word “Cloud Computing” is creating a buzz in the IT Industry today and is being looked upon as the foundation of the “Fourth Wave” of Technology termed as “IT Everywhere”.
AstroSeis: A 3D Boundary Element Modeling Code for Seismic Wavefields in Irregular Asteroids and Bodies

We developed a 3-D elastic Boundary Element Method (BEM) computer code, called AstroSeis, to model seismic wavefields in a body with an arbitrary shape, such as an asteroid. Besides the AstroSeis can handle arbitrary surface topography, it can deal with a liquid core in an asteroid model. Both the solid and liquid domains are homogenous in our current code. For seismic sources, we can use single forces or moment tensors. The AstroSeis is implemented in the frequency domain and the frequency-dependent Q can be readily incorporated. The code is in MATLAB and it is straightforward to set up the model to run our code. The frequency-domain calculation is advantageous to study the long-term elastic response of a celestial body due to a cyclic force such as the tidal force with no numerical dispersion issue suffered by many other methods requiring volume meshing. Our AstroSeis has been benchmarked with other methods such as normal modes summation and the direct solution method (DSM). This open-source AstroSeis will be a useful tool to study the interior and surface processes of asteroids.
EVOLUTIONARY DE RHAM-HODGE METHOD.

The de Rham-Hodge theory is a landmark of the 20 \begin{document}$ ^\text{th} $\end{document} Century's mathematics and has had a great impact on mathematics, physics, computer science, and engineering. This work introduces an evolutionary de Rham-Hodge method to provide a unified paradigm for the multiscale geometric and topological analysis of evolving manifolds constructed from a filtration, which induces a family of evolutionary de Rham complexes. While the present method can be easily applied to close manifolds, the emphasis is given to more challenging compact manifolds with 2-manifold boundaries, which require appropriate analysis and treatment of boundary conditions on differential forms to maintain proper topological properties. Three sets of unique evolutionary Hodge Laplacians are proposed to generate three sets of topology-preserving singular spectra, for which the multiplicities of zero eigenvalues correspond to exactly the persistent Betti numbers of dimensions 0, 1 and 2. Additionally, three sets of non-zero eigenvalues further reveal both topological persistence and geometric progression during the manifold evolution. Extensive numerical experiments are carried out via the discrete exterior calculus to demonstrate the potential of the proposed paradigm for data representation and shape analysis of both point cloud data and density maps. To demonstrate the utility of the proposed method, the application is considered to the protein B-factor predictions of a few challenging cases for which existing biophysical models break down.
Demographic Correlates of Acculturation and Sociocultural Adaptation: Comparing International and Domestic Students

A cross-sectional survey study of international (n=207) and domestic (n=173) students revealed, as expected, that international students had higher acculturative stress than domestic students, but this difference did not vary by marital status or length of stay. Also, women from high Uncertainty Avoidance (UA) and high Power Distance (PD) countries (vs. low UA and high PD countries) had greater social interaction acculturative stress (e.g., difficulty making friends). Thus, cultural background plays an important role in students’ adaptation and university counselors might need to collaborate with academic staff to help international students adjust. Female students from high UA and high PD countries may be especially in need of assistance to cope with acculturative stress.
Evolutionarily diverse LIM domain-containing proteins bind stressed actin filaments through a conserved mechanism

The actin cytoskeleton assembles into diverse load-bearing networks, including stress fibers (SFs), muscle sarcomeres, and the cytokinetic ring to both generate and sense mechanical forces. The LIM (Lin11, Isl- 1, and Mec-3) domain family is functionally diverse, but most members can associate with the actin cytoskeleton with apparent force sensitivity. Zyxin rapidly localizes via its LIM domains to failing SFs in cells, known as strain sites, to initiate SF repair and maintain mechanical homeostasis. The mechanism by which these LIM domains associate with stress fiber strain sites (SFSS) is not known. Additionally, it is unknown how widespread strain sensing is within the LIM protein family. We identify that the LIM domain-containing region of 18 proteins from the Zyxin, Paxillin, Tes, and Enigma proteins accumulate to SFSS. Moreover, the LIM domain region from the fission yeast protein paxillin like 1 (Pxl1) also localizes to SFSS in mammalian cells, suggesting that the strain sensing mechanism is ancient and highly conserved. We then used sequence and domain analysis to demonstrate that tandem LIM domains contribute additively, for SFSS localization. Employing in vitro reconstitution, we show that the LIM domain-containing region from mammalian zyxin and fission yeast Pxl1 binds to mechanically stressed F-actin networks but does not associate with relaxed actin filaments. We propose that tandem LIM domains recognize an F-actin conformation that is rare in the relaxed state but is enriched in the presence of mechanical stress.
Fair Contextual Multi-Armed Bandits: Theory and Experiments

When an AI system interacts with multiple users, it frequently needs to make allocation decisions. For instance, a virtual agent decides whom to pay attention to in a group setting, or a factory robot selects a worker to deliver a part. Demonstrating fairness in decision making is essential for such systems to be broadly accepted. We introduce a Multi-Armed Bandit algorithm with fairness constraints, where fairness is defined as a minimum rate that a task or a resource is assigned to a user. The proposed algorithm uses contextual information about the users and the task and makes no assumptions on how the losses capturing the performance of different users are generated. We provide theoretical guarantees of performance and empirical results from simulation and an online user study. The results highlight the benefit of accounting for contexts in fair decision making, especially when users perform better at some contexts and worse at others.
Reality as a simulation of reality: robot illusions, fundamental limits, and a physical demonstration

We consider problems in which robots conspire to present a view of the world that differs from reality. The inquiry is motivated by the problem of validating robot behavior physically despite there being a discrepancy between the robots we have at hand and those we wish to study, or the environment for testing that is available versus that which is desired, or other potential mismatches in this vein. After formulating the concept of a convincing illusion, essentially a notion of system simulation that takes place in the real world, we examine the implications of this type of simulability in terms of infrastructure requirements. Time is one important resource: some robots may be able to simulate some others but, perhaps, only at a rate that is slower than real-time. This difference gives a way of relating the simulating and the simulated systems in a form that is relative. We establish some theorems, including one with the flavor of an impossibility result, and providing several examples throughout. Finally, we present data from a simple multi-robot experiment based on this theory, with a robot navigating amid an unbounded field of obstacles."Truth is beautiful, without doubt; but so are lies."—Ralph Waldo Emerson
Monitoring Over the Long Term: Intermittent Deployment and Sensing Strategies for Multi-Robot Teams

In this paper, we formulate and solve the intermittent deployment problem, which yields strategies that couple when heterogeneous robots should sense an environmental process, with where a deployed team should sense in the environment. As a motivation, suppose that a spatiotemporal process is slowly evolving and must be monitored by a multi-robot team, e.g., unmanned aerial vehicles monitoring pasturelands in a precision agriculture context. In such a case, an intermittent deployment strategy is necessary as persistent deployment or monitoring is not cost-efficient for a slowly evolving process. At the same time, the problem of where to sense once deployed must be solved as process observations yield useful feedback for determining effective future deployment and monitoring decisions. In this context, we model the environmental process to be monitored as a spatiotemporal Gaussian process with mutual information as a criterion to measure our understanding of the environment. To make the sensing resource-efficient, we demonstrate how to use matroid constraints to impose a diverse set of homogeneous and heterogeneous constraints. In addition, to reflect the cost-sensitive nature of real-world applications, we apply budgets on the cost of deployed heterogeneous robot teams. To solve the resulting problem, we exploit the theories of submodular optimization and matroids and present a greedy algorithm with bounds on sub-optimality. Finally, Monte Carlo simulations demonstrate the correctness of the proposed method.
HOMEOWNERSHIP AND HOUSING TRANSITIONS: EXPLAINING THE DEMOGRAPHIC COMPOSITION

We document the evolution of homeownership rate across various age groups for the period 1995–2015. We find that variations in the homeownership rates are relatively large for the young, which is mostly driven by renter‐to‐owner transitions. In order to explain these empirical facts, we consider a life‐cycle model featuring housing tenure decisions. Housing is modeled as an indivisible and lumpy investment subject to both loan‐to‐value (LTV) and debt‐to‐income (DTI) credit constraints and transaction fees. Our analysis suggests that variations in the DTI limit play a crucial role in accounting for the uneven behavior across age groups.
Results on partial geometries with an abelian Singer group of rigid type

Abstract A partial geometry S admitting an abelian Singer group G is called of rigid type if all lines of S have a trivial stabilizer in G . In this paper, we show that if a partial geometry of rigid type has fewer than 1000000 points it must be the Van Lint–Schrijver geometry or be a hypothetical geometry with 1024 or 4096 or 194481 points, which provides evidence that partial geometries of rigid type are very rare. Along the way we also exclude an infinite set of parameters that originally seemed very promising for the construction of partial geometries of rigid type (as it contains the Van Lint–Schrijver parameters as its smallest case and one of the other cases we cannot exclude as the second member of this parameter family). We end the paper with a conjecture on this type of geometries.
Timing of diagnosis of complex lower urinary tract injury in the 30-day postoperative period following benign hysterectomy.

Background Complex lower urinary tract injury resulting from hysterectomy is a rare but highly morbid complication. Although intraoperative recognition reduces the risk of serious sequelae, observational studies have shown that most complex lower urinary tract injuries are recognized in the postoperative period. To date, limited research exists describing the timing of diagnosis of complex lower urinary tract injury or risk factors associated with complex lower urinary tract injury diagnosed in the postoperative period. Objective This analysis aimed to describe the time to diagnosis of complex lower urinary tract injury among women undergoing benign hysterectomy. We also aimed to identify the intraoperative risk factors for differences in type and timing of complex lower urinary tract injury in the 30-day postoperative period using a large prospective national surgical database. Study Design This was a retrospective analysis using the National Surgical Quality Improvement Program hysterectomy data set from 2014 to 2018. All benign hysterectomies were included. Sociodemographic factors, health status, surgeon type, and other operative characteristics were extracted. A complex lower urinary tract injury was defined as at least 1 ureteral obstruction, ureteral fistula, or bladder fistula diagnosed within the first 30 days following surgery. Bivariate and multivariate logistic regression and cox proportional hazards assessed differences in odds of and time until diagnosis of complex lower urinary tract injury. Proportional hazard assumptions were evaluated with martingale residuals and supremum tests. Significance thresholds were 0.05 for all analyses. Results In this study, 100,823 women met the inclusion criteria. Median time to diagnosis of complex lower urinary tract injury was 10 days (interquartile range, 3–19) and varied significantly based on type of injury (P Conclusion Greater than 91% of complex lower urinary tract injury diagnoses in the National Surgical Quality Improvement Program hysterectomy database were diagnosed after the day of surgery. Route of hysterectomy, concomitant apical suspension, and primary surgeon specialty are associated with differences in both type of injury and time until diagnosis. These intraoperative risk factors should be considered when assessing for complex lower urinary tract injury in the 30-day postoperative period.
A day late and a dollar short.

This is an invited commentary on robotic reoperative surgery without cardioplegia. Tips and shortfalls are discussed.
All-loop cuts from the Amplituhedron

The definition of the amplituhedron in terms of sign flips involves both one-loop constraints and the “mutual positivity” constraint. To gain an understanding of the all-loop integrand of $$ \mathcal{N}=4 $$ sYM requires understanding the crucial role played by mutual positivity. This paper is an attempt towards developing a procedure to introduce the complexities of mutual positivity in a systematic and controlled manner. As the first step in this procedure, we trivialize these constraints and understand the geometry underlying the remaining constraints to all loops and multiplicities. We present a host of configurations which correspond to various faces of the amplituhedron. The results we derive are valid at all multiplicities and loop orders for the maximally helicity violating (MHV) configurations. These include detailed derivations for the results in [1]. We conclude by indicating how one might move beyond trivial mutual positivity by presenting a series of configuration which re-introduce it bit by bit.
Periodic cyclic homology and derived de Rham cohomology

We use the Beilinson t -structure on filtered complexes and the Hochschild–Kostant–Rosenberg theorem to construct filtrations on the negative cyclic and periodic cyclic homologies of a scheme X with graded pieces given by the Hodge completion of the derived de Rham cohomology of X . Such filtrations have previously been constructed by Loday in characteristic zero and by Bhatt–Morrow–Scholze for p -complete negative cyclic and periodic cyclic homology in the quasisyntomic case.
A Laboratory for Magnetized Accretion Disk Model: Ultraviolet and X-Ray Emission from Cataclysmic Variable GK Persei

We analyze the ultraviolet spectrum of the cataclysmic variable GK Per at maximum light. The flat ultraviolet spectrum in this system requires a truncated inner accretion disk and an unusually flat radial temperature profile. This requirement is not satisfied by any nonmagnetic steady or nonsteady disk model. We consider a magnetized accretion disk model to explain the ultraviolet spectrum. The available data on the white dwarf spin and possible quasi-periodic oscillations constrain the magnetic field, B*, and the disk accretion rate, , to lie along a well-defined spin-equilibrium condition (/1017 g s−1) ~ 100(B*/107 G)2. Our self-consistent treatment of the magnetic torque on the disk flattens the disk temperature distribution outside the disk truncation radius. This modified temperature distribution is too steep to explain the UV spectrum for reasonable field strengths. X-ray heating is a plausible alternative to magnetic heating in GK Per. We estimate that the disk intercepts ~5% of the accretion energy in outburst, which results in an extra disk luminosity of ~5-10 L☉. Model spectra of optically thick disks are too blue to match observations. The UV spectrum of an optically thick disk with an optically thin, X-ray heated corona resembles the observed spectrum. The X-ray luminosity observed during the outburst indicates < 1018 g s-1, which is a factor of 10 lower than that required to explain the ultraviolet luminosity. Radiation drag on material flowing inward along the accretion column lowers the shock temperature and reduces the X-ray luminosity. Most of the accretion energy is then radiated at extreme ultraviolet wavelengths.
SURFACE LAYER ACCRETION IN CONVENTIONAL AND TRANSITIONAL DISKS DRIVEN BY FAR-ULTRAVIOLET IONIZATION

Whether protoplanetary disks accrete at observationally significant rates by the magnetorotational instability (MRI) depends on how well ionized they are. Disk surface layers ionized by stellar X-rays are susceptible to charge neutralization by small condensates, ranging from {approx}0.01 {mu}m sized grains to angstrom-sized polycyclic aromatic hydrocarbons (PAHs). Ion densities in X-ray-irradiated surfaces are so low that ambipolar diffusion weakens the MRI. Here we show that ionization by stellar far-ultraviolet (FUV) radiation enables full-blown MRI turbulence in disk surface layers. Far-UV ionization of atomic carbon and sulfur produces a plasma so dense that it is immune to ion recombination on grains and PAHs. The FUV-ionized layer, of thickness 0.01-0.1 g cm{sup -2}, behaves in the ideal magnetohydrodynamic limit and can accrete at observationally significant rates at radii {approx}> 1-10 AU. Surface layer accretion driven by FUV ionization can reproduce the trend of increasing accretion rate with increasing hole size seen in transitional disks. At radii {approx}<1-10 AU, FUV-ionized surface layers cannot sustain the accretion rates generated at larger distance, and unless turbulent mixing of plasma can thicken the MRI-active layer, an additional means of transport is needed. In the case of transitional disks, it could be provided by planets.
INFORMATION GEOMETRY, INFERENCE METHODS AND CHAOTIC ENERGY LEVELS STATISTICS

In this letter, we propose a novel information-geometric characterization of chaotic (integrable) energy level statistics of a quantum antiferromagnetic Ising spin chain in a tilted (transverse) external magnetic field. Finally, we conjecture our results might find some potential physical applications in quantum energy level statistics.
Role of reconnection in inertial kinetic-Alfvén turbulence

Recent observations of plasma fluctuations at scales below the ion Larmor radius have discovered magnetic reconnection events where only the electrons take part. This work proposes the first analytical explanation for this phenomenon. It demonstrates that the tearing instability, which leads to reconnection, is an inherent property of kinetic-scale plasma turbulence. Moreover, the authors show that while the electron-scale reconnection events are triggered by turbulence, they, in turn, shape the turbulent energy cascade.
Intercalated europium metal in epitaxial graphene on SiC

X-ray magnetic circular dichroism (XMCD) reveals the magnetic properties of intercalated europium metal under graphene on SiC(0001). The intercalation of Eu nanoclusters (average size 2.5 nm) between graphene and SiC substate are formed by deposition of Eu on epitaxially grown graphene that is subsequently annealed at various temperatures while keeping the integrity of the graphene layer. Using sum-rules analysis of the XMCD of Eu ${\mathrm{M}}_{4,5}$ edges at $T=15$ K, our samples show paramagnetic-like behavior with distinct anomaly at $T\ensuremath{\approx}90$ K, which may be related to the N\`eel transition, ${T}_{N}=91$ K, of bulk metal Eu. We find no evidence of ferromagnetism due to EuO or antiferromagnetism due to ${\mathrm{Eu}}_{2}{\mathrm{O}}_{3}$, indicating that the graphene layer protects the intercalated metallic Eu against oxidation over months of exposure to atmospheric environment.
Small curvature laminations in hyperbolic 3-manifolds

We show that if L is a codimension-one lamination in a finite volume hyperbolic 3‐manifold such that the principal curvatures of each leaf of L are all in the interval . ;/ for a fixed 2a0;1/ and no complementary region of L is an interval bundle over a surface, then each boundary leaf of L has a nontrivial fundamental group. We also prove existence of a fixed constant 0> 0 such that if L is a codimension-one lamination in a finite volume hyperbolic 3‐manifold such that the principal curvatures of each leaf of L are all in the interval . 0; 0/ and no complementary region of L is an interval bundle over a surface, then each boundary leaf of L has a noncyclic fundamental group. 57M50
The spin-Brauer diagram algebra

We investigate the spin-Brauer diagram algebra, denoted $$\mathrm{\mathbf SB}_n(\delta )$$ , that arises from studying an analogous form of Schur–Weyl duality for the action of the pin group on $$\mathbf {V}^{\otimes n} \otimes \varDelta $$ . Here, $$\mathbf {V}$$ is the standard N-dimensional complex representation of $$\mathbf {Pin}(N)$$ and $$\varDelta $$ is the spin representation. When $$\delta = N$$ is a positive integer, we define a surjective map $$\mathrm{\mathbf SB}_n(N) \twoheadrightarrow {{\mathrm{End}}}_{\mathbf {Pin}(N)}(\mathbf {V}^{\otimes n} \otimes \varDelta )$$ and show it is an isomorphism for $$N \ge 2n$$ . We show $$\mathrm{\mathbf SB}_n(\delta )$$ is a cellular algebra and use cellularity to characterize its irreducible representations.
Stability of Minkowski space and polyhomogeneity of the metric

We study the nonlinear stability of the $$(3+1)$$ -dimensional Minkowski spacetime as a solution of the Einstein vacuum equation. Similarly to our previous work on the stability of cosmological black holes, we construct the solution of the nonlinear initial value problem using an iteration scheme in which we solve a linearized equation globally at each step; we use a generalized harmonic gauge and implement constraint damping to fix the geometry of null infinity. The linear analysis is largely based on energy and vector field methods originating in work by Klainerman. The weak null condition of Lindblad and Rodnianski arises naturally as a nilpotent coupling of certain metric components in a linear model operator at null infinity. Upon compactifying $$\mathbb {R}^4$$ to a manifold with corners, with boundary hypersurfaces corresponding to spacelike, null, and timelike infinity, we show, using the framework of Melrose’s b-analysis, that polyhomogeneous initial data produce a polyhomogeneous spacetime metric. Finally, we relate the Bondi mass to a logarithmic term in the expansion of the metric at null infinity and prove the Bondi mass loss formula.
On higher energy decompositions and the sum-product phenomenon

Let A ⊂ ℝ be finite. We quantitatively improve the Balog–Wooley decomposition, that is A can be partitioned into sets B and C such that $ \begin{equation*} \max\{E^+(B) , E^{\times}(C)\} \lesssim |A|^{3 - 7/26}, \ \ \max \{E^+(B,A) , E^{\times}(C, A) \}\lesssim |A|^{3 - 1/4}. \end{equation*} $ We use similar decompositions to improve upon various sum–product estimates. For instance, we show $ \begin{equation*} |A+A| + |A A| \gtrsim |A|^{4/3 + 5/5277}. \end{equation*} $
Seasonal, Solar Zenith Angle, and Solar Flux Variations of O+ in the Topside Ionosphere of Mars

Using observations from Mars Atmosphere and Volatile EvolutioN's Neutral Gas and Ion Mass Spectrometer, we characterize the seasonal, solar zenith angle (SZA), and solar flux dependent variations of the O+ peak and the O+/O+2 ratio in the topside ionosphere of Mars.We find that the O+ peak is between 220 and 300 km and forms at a roughly constant neutral atmospheric pressure level of 10(−8.7±0.4) Pa. The O+ peak altitude also decreases with increasing SZA near the terminator and varies sinusoidally with an amplitude of 26 km over a period of one Mars year in response to the changing solar insolation. The O+ peak altitude reaches a maximum near Northern Winter solstice and Mars perihelion. The O+ peak density on the dayside has an average value of (1.1 ± 0.5) × 103 cm−3, has no dependence on SZA for SZAs up to ∼90◦, and is mainly controlled by the thermospheric O/CO2 ratio as predicted by photochemical theory. Above the O+ peak, the O+/O+2 ratio in the dayside ionosphere approaches a constant value of 1.1 ± 0.6, decreases with increasing SZA, and is highly variable on timescales of days or less.We discuss why the O+ peak is different than the main (M2) peak at Mars and why it is similar to the F2 peak at Earth.
Wess-Zumino term in tachyon effective action

We show that the source of RR field computed from the boundary state describing the decay of a non-BPS brane is reproduced by a particular form of the Wess-Zumino term in the tachyon effective action. We also obtain a simple expression of the S-charge associated with rolling tachyons.
The Onset of 3D Magnetic Reconnection and Heating in the Solar Corona

Magnetic reconnection, a fundamentally important process in many aspects of astrophysics, is believed to be initiated by the tearing instability of an electric current sheet, a region where magnetic field abruptly changes direction and electric currents build up. Recent studies have suggested that the amount of magnetic shear in these structures is a critical parameter for the switch-on nature of magnetic reconnection in the solar atmosphere, at fluid spatial scales much larger than kinetic scales. We present results of simulations of reconnection in 3D current sheets with conditions appropriate to the solar corona. Using high-fidelity simulations, we follow the evolution of the linear and non-linear 3D tearing instability, leading to reconnection. We find that, depending on the parameter space, magnetic shear can play a vital role in the onset of significant energy release and heating via non-linear tearing. Two regimes in our study exist, dependent on whether the current sheet is longer or shorter than the wavelength of the fastest growing parallel mode (in the corresponding infinite system), thus determining whether sub-harmonics are present in the actual system. In one regime, where the fastest growing parallel mode has sub-harmonics, the non-linear interaction of these sub-harmonics and the coalescence of 3D plasmoids dominates the non-linear evolution, with magnetic shear playing only a weak role in the amount of energy released. In the second regime, where the fastest growing parallel mode has no-sub-harmonics, then only strongly sheared current sheets, where oblique mode are strong enough to compete with the dominant parallel mode, show any significant energy release. We expect both regimes to exist on the Sun, and so our results have important consequences for the the question of reconnection onset in different solar physics applications.
On topological quantum computing with mapping class group representations

We propose an encoding for topological quantum computation utilizing quantum representations of mapping class groups. Leakage into a non-computational subspace seems to be unavoidable for universality in general. We are interested in the possible gate sets which can emerge in this setting. As a first step, we prove that for abelian anyons, all gates from these mapping class group representations are normalizer gates. Results of Van den Nest then allow us to conclude that for abelian anyons this quantum computing scheme can be simulated efficiently on a classical computer. With an eye toward more general anyon models we additionally show that for Fibonnaci anyons, quantum representations of mapping class groups give rise to gates which are not generalized Clifford gates.
Convergence of a crystalline algorithm for the heat equation in one dimension and for the motion of a graph by weighted curvature

Motion by (weighted) mean curvature is a geometric evolution law for surfaces, representing steepest descent with respect to (an)isotropic surface energy. It has been proposed that this motion could be computed by solving the analogous evolution law using a ``crystalline'' approximation to the surface energy. We present the first convergence analysis for a numerical scheme of this type. Our treatment is restricted to one dimensional surfaces (curves in the plane) which are graphs. In this context, the scheme amounts to a new algorithm for solving quasilinear parabolic equations in one space dimension.