cssi/SciSciGPT-SciSciNet huggingface dataset:
Degenerate versions of Green's theorem for Hall modules

Abstract Green's theorem states that the Hall algebra of the category of representations of a quiver over a finite field is a twisted bialgebra. Considering instead categories of orthogonal or symplectic quiver representations leads to a class of modules over the Hall algebra, called Hall modules, which are also comodules. A module theoretic analogue of Green's theorem, describing the compatibility of the module and comodule structures, is not known. In this paper we prove module theoretic analogues of Green's theorem in the degenerate settings of finitary Hall modules of Rep F 1 ( Q ) and constructible Hall modules of Rep C ( Q ) . The result is that the module and comodule structures satisfy a compatibility condition reminiscent of that of a Yetter–Drinfeld module.
Unfairness Discovery and Prevention For Few-Shot Regression

We study fairness in supervised few-shot meta-learning models that are sensitive to discrimination (or bias) in historical data. A machine learning model trained based on biased data tends to make unfair predictions for users from minority groups. Although this problem has been studied before, existing methods mainly aim to detect and control the dependency effect of the protected variables (e.g. race, gender) on target prediction based on a large amount of training data. These approaches carry two major drawbacks that (1) lacking showing a global cause-effect visualization for all variables; (2) lacking generalization of both accuracy and fairness to unseen tasks. In this work, we first discover discrimination from data using a causal Bayesian knowledge graph which not only demonstrates the dependency of the protected variable on target but also indicates causal effects between all variables. Next, we develop a novel algorithm based on risk difference in order to quantify the discriminatory influence for each protected variable in the graph. Furthermore, to protect prediction from unfairness, a fast-adapted bias-control approach in meta-learning is proposed, which efficiently mitigates statistical disparity for each task and it thus ensures independence of protected attributes on predictions based on biased and few-shot data samples. Distinct from existing meta-learning models, group unfairness of tasks are efficiently reduced by leveraging the mean difference between (un)protected groups for regression problems. Through extensive experiments on both synthetic and real-world data sets, we demonstrate that our proposed unfairness discovery and prevention approaches efficiently detect discrimination and mitigate biases on model output as well as generalize both accuracy and fairness to unseen tasks with a limited amount of training samples.
Composition Algorithm Adaptation in Service Oriented Systems

Architecting and constructing software systems using Service Oriented Architecture (SOA) is a widely employed paradigm. Application functionality is commonly delivered by composing Internet communicable software components or services. Using SOA, applications are constructed by a well-defined composition process that implements composition logic to meet an application’s functional and non-functional requirements. Various composition techniques have been proposed in the literature, with varying performance guarantees and resource usage. Service composition also has to adapt to unanticipated conditions posed by a highly dynamic environment due to changing services, evolving architectures, and user requirements. Current adaptive methodologies determine a composition technique at design time and adapt selection and binding of service at runtime. In this paper, we propose adaptation of composition techniques for each user request. Our data driven approach selects the best composition technique for a given application dependency graph. It learns adaptation rules from execution data and trades-off resource usage and solution quality of composition techniques.
Conifold Vacua with Small Flux Superpotential

We introduce a method for finding flux vacua of type IIB string theory in which the flux superpotential is exponentially small and at the same time one or more complex structure moduli are stabilized exponentially near to conifold points.
Fragile X mental retardation protein modulates somatic D-type K+ channels and action potential threshold in the mouse prefrontal cortex.

We demonstrate that fragile X mental retardation protein (FMRP), which is absent in fragile X syndrome (FXS), regulates D-type potassium channels in prefrontal cortex L5 pyramidal neurons with subc...
Dynamic evolution of great ape Y chromosomes

The mammalian male-specific Y chromosome plays a critical role in sex determination and male fertility. However, because of its repetitive and haploid nature, it is frequently absent from genome assemblies and remains enigmatic. The Y chromosomes of great apes represent a particular puzzle: their gene content is more similar between human and gorilla than between human and chimpanzee, even though human and chimpanzee share a more recent common ancestor. To solve this puzzle, here we constructed a dataset including Ys from all extant great ape genera. We generated assemblies of bonobo and orangutan Ys from short and long sequencing reads and aligned them with the publicly available human, chimpanzee, and gorilla Y assemblies. Analyzing this dataset, we found that the genus Pan, which includes chimpanzee and bonobo, experienced accelerated substitution rates. Pan also exhibited elevated gene death rates. These observations are consistent with high levels of sperm competition in Pan Furthermore, we inferred that the great ape common ancestor already possessed multicopy sequences homologous to most human and chimpanzee palindromes. Nonetheless, each species also acquired distinct ampliconic sequences. We also detected increased chromatin contacts between and within palindromes (from Hi-C data), likely facilitating gene conversion and structural rearrangements. Our results highlight the dynamic mode of Y chromosome evolution and open avenues for studies of male-specific dispersal in endangered great ape species.
Diagnostic Prediction with Sequence-of-sets Representation Learning for Clinical Events.

Electronic health records (EHRs) contain both ordered and unordered chronologies of clinical events that occur during a patient encounter. However, during data preprocessing steps, many predictive models impose a predefined order on unordered clinical events sets (e.g., alphabetical, natural order from the chart, etc.), which is potentially incompatible with the temporal nature of the sequence and predictive task. To address this issue, we propose DPSS, which seeks to capture each patient’s clinical event records as sequences of event sets. For each clinical event set, we assume that the predictive model should be invariant to the order of concurrent events and thus employ a novel permutation sampling mechanism. This paper evaluates the use of this permuted sampling method given different data-driven models for predicting a heart failure (HF) diagnosis in subsequent patient visits. Experimental results using the MIMIC-III dataset show that the permutation sampling mechanism offers improved discriminative power based on the area under the receiver operating curve (AUROC) and precision-recall curve (pr-AUC) metrics as HF diagnosis prediction becomes more robust to different data ordering schemes.
Hybrid Differential Dynamic Programming for Planar Manipulation Primitives

We present a hybrid differential dynamic programming (DDP) algorithm for closed-loop execution of manipulation primitives with frictional contact switches. Planning and control of these primitives is challenging as they are hybrid, under-actuated, and stochastic. We address this by developing hybrid DDP both to plan finite horizon trajectories with a few contact switches and to create linear stabilizing controllers. We evaluate the performance and computational cost of our framework in ablations studies for two primitives: planar pushing and planar pivoting. We find that generating pose-to-pose closed-loop trajectories from most configurations requires only a couple (one to two) hybrid switches and can be done in reasonable time (one to five seconds). We further demonstrate that our controller stabilizes these hybrid trajectories on a real pushing system. A video describing our work can be found at https://youtu.be/YGSe4cUfq6Q.
Multivariate analysis reveals a generalizable human electrophysiological signature of working memory load

Working memory (WM) is an online memory system that is critical for holding information in a rapidly accessible state during ongoing cognitive processing. Thus, there is strong value in methods that provide a temporally resolved index of WM load. While univariate EEG signals have been identified that vary with WM load, recent advances in multivariate analytic approaches suggest that there may be rich sources of information that do not generate reliable univariate signatures. Here, using data from four published studies (n = 286 and >250,000 trials), we demonstrate that multivariate analysis of EEG voltage topography provides a sensitive index of the number of items stored in WM that generalizes to novel human observers. Moreover, multivariate load detection ("mvLoad") can provide robust information at the single-trial level, exceeding the sensitivity of extant univariate approaches. We show that this method tracks WM load in a manner that is (1) independent of the spatial position of the memoranda, (2) precise enough to differentiate item-by-item increments in the number of stored items, (3) generalizable across distinct tasks and stimulus displays, and (4) correlated with individual differences in WM behavior. Thus, this approach provides a powerful complement to univariate analytic approaches, enabling temporally resolved tracking of online memory storage in humans.
Private and communication-efficient edge learning: a sparse differential gaussian-masking distributed SGD approach

With the rise of machine learning (ML) and the proliferation of smart mobile devices, recent years have witnessed a surge of interest in performing ML in wireless edge networks. In this paper, we consider the problem of jointly improving data privacy and communication efficiency of distributed edge learning, both of which are critical performance metrics in wireless edge network computing. Toward this end, we propose a new distributed stochastic gradient method with sparse differential Gaussian-masked stochastic gradients (SDM-DSGD) for non-convex distributed edge learning. Our main contributions are three-fold: i) We theoretically establish the privacy and communication efficiency performance guarantee for our SDM-DSGD method, which outperforms all existing works; ii) We propose a generalized differential-coded DSGD update, which enables a much lower transmit probability for gradient sparsification, and provides an [EQUATION] convergence rate; and iii) We reveal theoretical insights and offer practical design guidelines for the interactions between privacy preservation and communication efficiency - two conflicting performance goals. We conduct extensive experiments with a variety of learning models on MNIST and CIFAR-10 datasets to verify our theoretical findings.
Leader-following almost output consensus for linear multi-agent systems with disturbance-affected unstable zero dynamics

Abstract In this paper, we formulate and investigate the leader-following almost output consensus problem for linear multi-agent systems with disturbance affected unstable zero dynamics. Conditions on the communication topology, agent dynamics and the way the disturbances affect the zero dynamics are established under which low-and-high gain based consensus protocols are designed. These protocols are shown to achieve leader-following almost output consensus, that is, output consensus of the system can be achieved to an arbitrary level of accuracy with the states remain bounded in the absence of the disturbances, and when the system is operating in output consensus within the desired accuracy, the L 2 -gain from the disturbances to the difference between each follower agent’s output with and without the disturbances from the same initial condition can be made arbitrarily small. A numerical example is shown to verify the theoretical results.
Evaluating Simple Ab Initio Models of the Hydrated Electron: The Role of Dynamical Fluctuations.

Despite its importance in electron transfer reactions and radiation chemistry, there has been disagreement over the fundamental nature of the hydrated electron, such as whether or not it resides in...
Resiliency by Retrograded Communication-the Revival of Shortwave as a Military Communication Channel

In the last three decades, the great powers have become increasingly dependent on satellite communication (SATCOM), very high frequency (VHF), and ultrahigh frequency providing high bandwidth line-of-sight communications. These military communication channels lack resilience because an electronic warfare (EW) campaign can affect both VHF and SATCOM simultaneously. The 1940s preferred spectrum, high frequency, with its different propagation patterns, offers an opportunity for military communication resiliency in the 21st century. The concept of retrograding could give an operational advantage and create the ability to sustain communication in EW saturated environment.
Current medical management of hereditary angioedema: Follow-up survey of US physicians.

BACKGROUND Physician surveys on hereditary angioedema (HAE) management in 2010 and 2013 revealed important trends in HAE care. OBJECTIVE To evaluate current HAE management and the impact of new treatment options on physician practice patterns over time. METHODS During June and July 2019, 5382 physicians were contacted by means of postal mail to complete a 47-question survey; 177 responded (3%). RESULTS Across the 3 surveys, the home replaced the emergency department as the most typically reported setting for HAE attack treatment (54.3% vs 11.6% in 2010 and 32.5% in 2013; P < .001). Physicians reported C1 esterase inhibitor (C1-INH) as the most typically prescribed long-term prophylactic treatment (LTP) (60.0% vs 20.4% in 2010 and 56.7% in 2013; P < .001). Subcutaneous LTP medications were most typically prescribed over intravenous (C1-INH, 41.4%; subcutaneous lanadelumab, 21%; intravenous C1-INH, 18.6%). Danazol, the most frequently prescribed LTP treatment, dropped to 6.4% (55.8% in 2010 and 23.4% in 2013; P < .001). The strongest nonefficacy factor influencing clinician treatment choice changed over time, with cost and (or) insurance coverage increasing to 43.7% (from 24.4% in 2010 and 40.5% in 2013; P = .001), whereas the concern over adverse effects dropped to 16.2% (from 55.8% in 2010 and 29.5% in 2013; P < .001). Physician-reported patient satisfaction remains high, with only 1.5% of physicians indicating patients are not satisfied with treatment. CONCLUSION The US physician survey data reflect improvements in the HAE management in recent years. Therapeutic advances in HAE have led to reported higher rates of home treatment of HAE attacks, reduced concern for adverse treatment effects, and high levels of patient satisfaction.
Gaussian graphical models with toric vanishing ideals

Gaussian graphical models are semi-algebraic subsets of the cone of positive definite covariance matrices. They are widely used throughout natural sciences, computational biology and many other fields. Computing the vanishing ideal of the model gives us an implicit description of the model. In this paper, we resolve two conjectures given by Sturmfels and Uhler. In particular, we characterize those graphs for which the vanishing ideal of the Gaussian graphical model is generated in degree 1 and 2. These turn out to be the Gaussian graphical models whose ideals are toric ideals, and the resulting graphs are the 1-clique sums of complete graphs.
Augmented projections for ptychographic imaging

Ptychography is a popular technique to achieve diffraction limited resolution images of a two- or three-dimensional sample using high frame rate detectors. We introduce a relaxation of common projection algorithms to account for instabilities given by intensity and background fluctuations, position errors, or poor calibration using multiplexing illumination. This relaxation introduces an additional phasing optimization at every step that enhances the convergence rate of common projection algorithms. Numerical tests exhibit the exact recovery of the object and the perturbations when there is high redundancy in the data.
Realism about the Wave Function

A century after the discovery of quantum mechanics, the meaning of quantum mechanics still remains elusive. This is largely due to the puzzling nature of the wave function, the central object in quantum mechanics. If we are realists about quantum mechanics, how should we understand the wave function? What does it represent? What is its physical meaning? Answering these questions would improve our understanding of what it means to be a realist about quantum mechanics. In this survey article, I review and compare several realist interpretations of the wave function. They fall into three categories: ontological interpretations, nomological interpretations, and the sui generis interpretation. For simplicity, I will focus on non-relativistic quantum mechanics.
Geometric quantum speed limits: a case for Wigner phase space

The quantum speed limit is a fundamental upper bound on the speed of quantum evolution. However, the actual mathematical expression of this fundamental limit depends on the choice of a measure of distinguishability of quantum states. We show that quantum speed limits are qualitatively governed by the Schatten-p-norm of the generator of quantum dynamics. Since computing Schatten-p-norms can be mathematically involved, we then develop an alternative approach in Wigner phase space. We find that the quantum speed limit in Wigner space is fully equivalent to expressions in density operator space, but that the new bound is significantly easier to compute. Our results are illustrated for the parametric harmonic oscillator and for quantum Brownian motion.
The virialization density of peaks with general density profiles under spherical collapse

We calculate the non-linear virialization density, Δc, of halos under spherical collapse from peaks with an arbitrary initial and final density profile. This is in contrast to the standard calculation of Δc which assumes top-hat profiles. Given our formalism, the non-linear halo density can be calculated once the shape of the initial peak's density profile and the shape of the virialized halo's profile are provided. We solve for Δc for halos in an Einstein de-Sitter and a ΛCDM universe. As examples, we consider power-law initial profiles as well as spherically averaged peak profiles calculated from the statistics of a Gaussian random field. We find that, depending on the profiles used, Δc is smaller by a factor of a few to as much as a factor of 10 as compared to the density given by the standard calculation ( ≈ 200). Using our results, we show that, for halo finding algorithms that identify halos through an over-density threshold, the halo mass function measured from cosmological simulations can be enhanced at all halo masses by a factor of a few. This difference could be important when using numerical simulations to assess the validity of analytic models of the halo mass function.
isoTarget: A Genetic Method for Analyzing the Functional Diversity of Splicing Isoforms In Vivo.

Protein isoforms generated by alternative splicing contribute to proteome diversity. Because of the lack of effective techniques, the isoform-specific function, expression, localization, and signaling of endogenous proteins are unknown for most genes. Here, we report a genetic method, isoTarget, for multi-purpose studies of targeted isoforms in select cells. Applying isoTarget to two isoforms of Drosophila Dscam, Dscam[TM1] and [TM2], we found that, in neurons, endogenous Dscam[TM1] is in dendrites, whereas Dscam[TM2] is in both dendrites and axons. We demonstrate that the difference in subcellular localization, rather than biochemical properties, leads to the two isoforms' functional differences. Moreover, we show that the subcellular enrichment of functional partners results in a DLK/Wallenda-Dscam[TM2]-Dock signaling cascade in axons. We further apply isoTarget to study two isoforms of a GABA receptor to demonstrate its general applicability. isoTarget is an effective technique for studying how alternative splicing enhances proteome complexity.
Strictly non-adiabatic quantum control of the acetylene dication using an infrared field.

We demonstrate the existence of a strictly non-adiabatic control pathway in deprotonation of the acetylene dication. This pathway is identified experimentally by measuring a kinetic energy shift in an ion coincidence experiment. We use a time dependent Schrodinger equation simulation to identify which properties most strongly affect our control. We find that resonant control around conical intersections is limited by the speed of non-adiabatic dynamics.
Extremality of loci of hyperelliptic curves with marked Weierstrass points

The locus of genus-two curves with n marked Weierstrass points has codimension n inside the moduli space of genus-two curves with n marked points, for n ≤ 6. It is well known that the class of the closure of the divisor obtained for n = 1 spans an extremal ray of the cone of effective divisor classes. We generalize this result for all n: we show that the class of the closure of the locus of genus-two curves with n marked Weierstrass points spans an extremal ray of the cone of effective classes of codimension n, for n ≤ 6. A related construction produces extremal nef curve classes in moduli spaces of pointed elliptic curves.
Virtual D-branes

Abstract Using a formalism developed to include collective coordinates, we calculate the contributions to S-matrix elements due to off-shell D-branes in a string coupling expansion. The formalism is further used to establish a two-dimensional computation of higher order corrections to the D-brane tension, both for the bosonic and the supersymmetric cases.
Automated coronary artery atherosclerosis detection and weakly supervised localization on coronary CT angiography with a deep 3-dimensional convolutional neural network.

Abstract We propose a fully automated algorithm based on a deep learning framework enabling screening of a coronary computed tomography angiography (CCTA) examination for confident detection of the presence or absence of coronary artery atherosclerosis. The system starts with extracting the coronary arteries and their branches from CCTA datasets and representing them with multi-planar reformatted volumes; pre-processing and augmentation techniques are then applied to increase the robustness and generalization ability of the system. A 3-dimensional convolutional neural network (3D-CNN) is utilized to model pathological changes (e.g., atherosclerotic plaques) in coronary vessels. The system learns the discriminatory features between vessels with and without atherosclerosis. The discriminative features at the final convolutional layer are visualized with a saliency map approach to provide visual clues related to atherosclerosis likelihood and location. We have evaluated the system on a reference dataset representing 247 patients with atherosclerosis and 246 patients free of atherosclerosis. With five fold cross-validation, an Accuracy = 90.9%, Positive Predictive Value = 58.8%, Sensitivity = 68.9%, Specificity of 93.6%, and Negative Predictive Value (NPV) = 96.1% are achieved at the artery/branch level with threshold 0.5. The average area under the receiver operating characteristic curve is 0.91. The system indicates a high NPV, which may be potentially useful for assisting interpreting physicians in excluding coronary atherosclerosis in patients with acute chest pain.
Characterization of Small-Molecule-Induced Changes in Parkinson's-Related Trafficking via the Nedd4 Ubiquitin Signaling Cascade

Summary The benzdiimidazole NAB2 rescues α-synuclein-associated trafficking defects associated with early onset Parkinson's disease in a Nedd4-dependent manner. Despite identification of E3 ubiquitin ligase Nedd4 as a putative target of NAB2, its molecular mechanism of action has not been elucidated. As such, the effect of NAB2 on Nedd4 activity and specificity was interrogated through biochemical, biophysical, and proteomic analyses. NAB2 was found to bind Nedd4 (KDapp = 42 nM), but this binding is side chain mediated and does not alter its conformation or ubiquitination kinetics in vitro. Nedd4 co-localizes with trafficking organelles, and NAB2 exposure did not alter its co-localization. Ubiquitin enrichment coupled proteomics revealed that NAB2 stimulates ubiquitination of trafficking-associated proteins, most likely through modulating the substrate specificity of Nedd4, providing a putative protein network involved in the NAB2 mechanism and revealing trafficking scaffold protein TFG as a Nedd4 substrate.
Nonlinear Evolution of Ion Kinetic Instabilities in the Solar Wind

In-situ observations of the solar wind (SW) plasma from 0.29 to 1 AU show that the protons and $\alpha $ particles are often non-Maxwellian, with evidence of kinetic instabilities, temperature anisotropies, differential ion streaming, and associated magnetic fluctuations spectra. The kinetic instabilities in the SW multi-ion plasma can lead to preferential heating of $\alpha $ particles and the dissipation of magnetic fluctuation energy, affecting the kinetic and global properties of the SW. Using for the first time a three-dimensional hybrid model, where ions are modeled as particles using the Particle-In-Cell (PIC) method and electrons are treated as fluid, we study the onset, nonlinear evolution and dissipation of ion kinetic instabilities. The Alfven/ion cyclotron, and the ion drift instabilities are modeled in the region close to the Sun ( $\sim 10R_{s}$ ). Solar wind expansion is incorporated in the model. The model produces self-consistent non-Maxwellian velocity distribution functions (VDFs) of unstable ion populations, the associated temperature anisotropies, and wave spectra for several typical SW instability cases in the nonlinear growth and saturation stage of the instabilities. The 3D hybrid modeling of the multi-ion SW plasma could be used to study the SW acceleration region close to the Sun, which will be explored by the Parker Solar Probe mission.
Spectropolarimetry of the Type II Supernovae 1997ds, 1998A, and 1999gi

ABSTRACT We present single‐epoch spectropolarimetry of the Type II supernovae (SNe II) 1997ds, 1998A, and 1999gi. SN 1997ds and SN 1998A were both observed during the early photospheric phase, less than 50 days after explosion, while spectropolarimetry of SN 1999gi was obtained near the start of the transition to the nebular phase, about 110 days after explosion. Uncorrected for interstellar polarization (ISP), SN 1997ds is characterized by \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $p_{V}=0.85\% \pm 0.02\% $ \end{document} ...
Moduli spaces of representations of special biserial algebras

We show that the irreducible components of any moduli space of semistable representations of a special biserial algebra are always isomorphic to products of projective spaces of various dimensions. This is done by showing that irreducible components of varieties of representations of special biserial algebras are isomorphic to irreducible components of products of varieties of circular complexes, and therefore normal, allowing us to apply recent results of the second and third authors on moduli spaces.
Trait-space patterning and the role of feedback in antigen-immunity coevolution

The authors show that when cross-reactive interactions are sufficiently asymmetric, coevolving populations of antigens and immune receptors simultaneously speciate. Further, these phenotypic patterns resonate and hence drive the arms race off balance. This study reveals the role of mutual feedback in yielding dynamic transients and identifies cross-reactivity as an evolvable regulator of diversity and population fate.
MAIN SEQUENCE EVOLUTION WITH LAYERED SEMICONVECTION

Semiconvection - mixing that occurs in regions that are stable when considering compositional gradients, but unstable when ignoring them - is shown to have the greatest potential impact on main sequence stars with masses in the range 1.2 - 1.7 solar masses. We present the first stellar evolution calculations using a prescription for semiconvection derived from extrapolation of direct numerical simulations of double-diffusive mixing down to stellar parameters. The dominant mode of semiconvection in stars is layered semiconvection, where the layer height is an adjustable parameter analogous to the mixing length in convection. The rate of mixing across the semiconvective region is sensitively dependent on the layer height. We find that there is a critical layer height that separates weak semiconvective mixing (where evolution is well-approximated by using the Ledoux criterion) from strong semiconvective mixing (where evolution is well-approximated by using the Schwarzschild criterion). This critical layer height is much smaller than the minimum layer height expected from simulations so we predict that for realistic layer heights, the evolution is nearly the same as a model ran with the Schwarzschild criterion. We also investigate the effects of compositional gradient smoothing, finding that it causes convective cores to artificially shrink in the absence of additional mixing beyond the convective boundary. Layered semiconvection with realistic layer heights provides enough such mixing that stars will still evolve as if the Schwarzschild criterion is employed. Finally, we discuss the potential of detecting such semiconvection and its implication on convective core sizes in solar-like oscillators.
Surface Impedance Determination via Numerical Resolution of the Inverse Helmholtz Problem

Assigning boundary conditions, such as acoustic impedance, to the frequency domain thermoviscous wave equations (TWE), derived from the linearized Navier-Stokes equations (LNSE) poses a Helmholtz problem, solution to which yields a discrete set of complex eigenfunctions and eigenvalue pairs. The proposed method -- the inverse Helmholtz solver (iHS) -- reverses such procedure by returning the value of acoustic impedance at one or more unknown impedance boundaries (IBs) of a given domain, via spatial integration of the TWE for a given real-valued frequency with assigned conditions on other boundaries. The iHS procedure is applied to a second-order spatial discretization of the TWEs on an unstructured staggered grid arrangement. Only the momentum equation is extended to the center of each IB face where pressure and velocity components are co-located and treated as unknowns. The iHS is finally closed via assignment of the surface gradient of pressure phase over the IBs, corresponding to assigning the shape of the acoustic waveform at the IB. The iHS procedure can be carried out independently for different frequencies, making it embarrassingly parallel, and able to return the complete broadband complex impedance distribution at the IBs in any desired frequency range to arbitrary numerical precision. The iHS approach is first validated against Rott's theory for viscous rectangular and circular ducts. The impedance of a toy porous cavity with a complex geometry is then reconstructed and validated with companion fully compressible unstructured Navier-Stokes simulations resolving the cavity geometry. Verification against one-dimensional impedance test tube calculations based on time-domain impedance boundary conditions (TDIBC) is also carried out. Finally, results from a preliminary analysis of a thermoacoustically unstable cavity are presented.
Planetary nebulae in face-on spiral galaxies. ii. planetary nebula spectroscopy

As the second step in our investigation of the mass-to-light ratio of spiral disks, we present the results of a spectroscopic survey of planetary nebulae (PNe) in five nearby, low-inclination galaxies: IC 342, M74 (NGC 628), M83 (NGC 5236), M94 (NGC 4736), and M101 (NGC 5457). Using 50 setups of the WIYN/Hydra and Blanco/Hydra spectrographs, and 25 observations with the Hobby-Eberly Telescope's Medium Resolution Spectrograph, we determine the radial velocities of 99, 102, 162, 127, and 48 PNe, respectively, to a precision better than 15 km s–1. Although the main purpose of this data set is to facilitate dynamical mass measurements throughout the inner and outer disks of large spiral galaxies, our spectroscopy has other uses as well. Here, we co-add these spectra to show that, to first order, the [O III] and Balmer line ratios of PNe vary little over the top ~1.5 mag of the PN luminosity function. The only obvious spectral change occurs with [N II], which increases in strength as one proceeds down the luminosity function. We also show that typical [O III]-bright planetaries have E(B – V) ~ 0.2 of circumstellar extinction, and that this value is virtually independent of [O III] luminosity. We discuss the implications this has for understanding the population of PN progenitors.
Proton radius puzzle and quantum gravity at the Fermi scale

We show how the “proton radius puzzle” emerging from the measurement of the Lamb shift in muonic hydrogen may be solved by means of a binding energy contribution due to an effective Yukawian gravitational potential related to charged weak interactions. The residual discrepancy from the experimental result should be mainly attributable to the need for the experimental determination of the gravitational radius of the proton. The absence of an analogous contribution in the Lamb shift of electronic hydrogen should imply the existence of generation-dependent interactions, corroborating previous proposals. Muonic hydrogen plays a crucial role to test possible scenarios for a gravitoweak unification, with weak interactions seen as manifestations of quantum gravity effects at the Fermi scale.
Surface effects on nitrogen vacancy centers neutralization in diamond

The performance of nitrogen vacancy (NV−) based magnetic sensors strongly depends on the stability of nitrogen vacancy centers near the diamond surface. The sensitivity of magnetic field detection is diminished as the NV− turns into the neutralized charge state NV0. We investigate the neutralization of NV− and calculate the ratio of NV0 to total NV (NV−+NV0) caused by a hydrogen terminated diamond with a surface water layer. We find that NV− neutralization exhibits two distinct regions: near the surface, where the NV− is completely neutralized, and in the bulk, where the neutralization ratio is inversely proportional to depth following the electrostatic force law. In addition, small changes in concentration can lead to large differences in neutralization behavior. This phenomenon allows one to carefully control the concentration to decrease the NV− neutralization. The presence of nitrogen dopant greatly reduces NV− neutralization as the nitrogen ionizes in preference to NV− neutralization at the same dept...
Hilbert modular surfaces for square discriminants and elliptic subfields of genus 2 function fields

We compute explicit rational models for some Hilbert modular surfaces corresponding to square discriminants, by connecting them to moduli spaces of elliptic K3 surfaces. Since they parametrize decomposable principally polarized abelian surfaces, they are also moduli spaces for genus-2 curves covering elliptic curves via a map of fixed degree. We thereby extend classical work of Jacobi, Hermite, Bolza etc., and more recent work of Kuhn, Frey, Kani, Shaska, Volklein, Magaard and others, producing explicit families of reducible Jacobians. In particular, we produce a birational model for the moduli space of pairs (C, E) of a genus 2 curve C and elliptic curve E with a map of degree n from C to E, as well as a tautological family over the base, for $$2 \le n \le 11$$ 2 ≤ n ≤ 11 . We also analyze the resulting models from the point of view of arithmetic geometry, and produce several interesting curves on them.
Geometry and stability of tautological bundles on Hilbert schemes of points

The purpose of this paper is to explore the geometry and establish the slope stability of tautological vector bundles on Hilbert schemes of points on smooth surfaces. By establishing stability in general we complete a series of results of Schlickewei and Wandel who proved the slope stability of these vector bundles for Hilbert schemes of 2 points or 3 points on K3 or abelian surfaces with Picard group restrictions. In exploring the geometry we show that every sufficiently positive semistable vector bundle on a smooth curve arises as the restriction of a tautological vector bundle on the Hilbert scheme of points on the projective plane. Moreover we show the tautological bundle of the tangent bundle is naturally isomorphic to the sheaf of vector fields tangent to the divisor which consists of nonreduced subschemes.
On the Power Allocation Limits for Downlink Multi-User NOMA with QoS

The fundamental power allocation requirements for NOMA systems with minimum quality of service (QoS) requirements are investigated. For any minimum QoS rate $R_0$, the limits on the power allocation coefficients for each user are derived, such that any power allocation coefficient outside of these limits creates an outage with probability equal to 1. The power allocation coefficients that facilitate each user's success of performing successive interference cancellation (SIC) and decoding its own signal are derived, and are found to depend only on the target rate $R_0$ and the number of total users $K$. It is then proven that using these power allocation coefficients create the same outage event as if using orthogonal multiple access (OMA), which proves that the outage performance of NOMA with a fixed-power scheme can matched that of OMA for all users simultaneously. Simulations confirm the theoretical results, and also demonstrate that a power allocation strategy exists that can improve the outage performance of NOMA over OMA, even with a fixed-power strategy.
Comments on “There Is No Axiomatic System for the Quantum Theory”

In a recent paper, Nagata (Int. J. Theor. Phys. 48(12):3532, 2009) claims to derive inconsistencies from quantum mechanics. In this paper, we show that the inconsistencies do not come from quantum mechanics, but from extra assumptions about the reality of observables.
Negative thermal expansion in the Prussian Blue analog Zn3[Fe(CN)6]2: X-ray diffraction and neutron vibrational studies

The cubic Prussian Blue (PB) analog, Zn3 [Fe(CN)6]2, has been studied by X-ray powder diffraction and inelastic neutron scattering (INS). X-ray data collected at 300 and 84 K revealed negative thermal expansion (NTE) behaviour for this material. The NTE coefficient was found to be −31.1 × 10−6 K−1. The neutron vibrational spectrum for Zn3[Fe(CN)6]2.xH2O, was studied in detail. The INS spectrum showed well-defined, well-separated bands corresponding to the stretching of and deformation modes of the Fe and Zn octahedra, all below 800 cm−1.
The fundamental connections between classical Hamiltonian mechanics, quantum mechanics and information entropy

We show that the main difference between classical and quantum systems can be understood in terms of information entropy. Classical systems can be considered the ones where the internal dynamics ca...
A rank rigidity result for CAT(0) spaces with one-dimensional Tits boundaries

We prove the following rank rigidity result for proper CAT(0) spaces with one-dimensional Tits boundaries: Let $\Gamma$ be a group acting properly discontinuously, cocompactly, and by isometries on such a space $X$. If the Tits diameter of $\partial X$ equals $\pi$ and $\Gamma$ does not act minimally on $\partial X$, then $\partial X$ is a spherical building or a spherical join. If $X$ is also geodesically complete, then $X$ is a Euclidean building, higher rank symmetric space, or a nontrivial product. Much of the proof, which involves finding a Tits-closed convex building-like subset of $\partial X$, does not require the Tits diameter to be $\pi$, and we give an alternate condition that guarantees rigidity when this hypothesis is removed, which is that a certain invariant of the group action be even.
SSHMT: Semi-supervised Hierarchical Merge Tree for Electron Microscopy Image Segmentation

Region-based methods have proven necessary for improving segmentation accuracy of neuronal structures in electron microscopy (EM) images. Most region-based segmentation methods use a scoring function to determine region merging. Such functions are usually learned with supervised algorithms that demand considerable ground truth data, which are costly to collect. We propose a semi-supervised approach that reduces this demand. Based on a merge tree structure, we develop a differentiable unsupervised loss term that enforces consistent predictions from the learned function. We then propose a Bayesian model that combines the supervised and the unsupervised information for probabilistic learning. The experimental results on three EM data sets demonstrate that by using a subset of only \(3\,\%\) to \(7\,\%\) of the entire ground truth data, our approach consistently performs close to the state-of-the-art supervised method with the full labeled data set, and significantly outperforms the supervised method with the same labeled subset.
Making Terrestrial Planets: High Temperatures, FU Orionis Outbursts, Earth, and Planetary System Architectures

Current protoplanetary dust coagulation theory does not predict dry silicate planetesimals, in tension with the Earth. While remedies to this predicament have been proposed, they have generally failed numerical studies, or are in tension with the Earth's (low, volatility dependent) volatile and moderately volatile elemental abundances. Expanding on the work of Boley et al., we examine the implications of molten grain collisions and find that they may provide a solution to the dry silicate planetesimal problem. Furthermore, the source of the heating, whether it be a hot inner disk or an FU Orionis scale accretion event, would dictate the location of the resulting planetesimals, potentially controlling subsequent planetary system architectures. We hypothesize that systems that did undergo FU Orionis scale accretion events host planetary systems similar to our own, while ones that did not undergo such an accretion event instead host very close in, tightly packed planets such as those seen by Kepler.
What we don't know about time

String theory has transformed our understanding of geometry, topology and space-time. Thus, for this special issue of Foundations of Physics commemorating “Forty Years of String Theory”, it seems appropriate to step back and ask what we do not understand. As I will discuss, time remains the least understood concept in physical theory. While we have made significant progress in understanding space, our understanding of time has not progressed much beyond the level of a century ago when Einstein introduced the idea of space-time as a combined entity. Thus, I will raise a series of open questions about time, and will review some of the progress that has been made as a roadmap for the future.
Inviscid Dynamical Structures Near Couette Flow

Consider inviscid fluids in a channel \({\{-1\leqq y\leqq1\}}\) . For the Couette flow u0 = (y, 0), the vertical velocity of solutions to the linearized Euler equation at u0 decays in time. Whether the same happens at the non-linear level is an open question. Here we study issues related to this problem. First, we show that in any (vorticity) \({H^{s}\left(s \frac{3}{2}\right)}\) neighborhoods of Couette flow, we show that there exist no non-parallel steadily travelling flows \({\varvec{v}\left(x-ct,y\right)}\) , and no unstable shears. This suggests that the long time dynamics in \({H^{s}\left(s>\frac{3}{2}\right)}\) neighborhoods of Couette flow might be much simpler. Such contrasting dynamics in Hs spaces with the critical power \({s=\frac{3}{2}}\) is a truly nonlinear phenomena, since the linear inviscid damping near Couette flow is true for any initial vorticity in L2.
Progenitors of Type IIb Supernovae. I. Evolutionary Pathways and Rates

Type IIb supernovae (SNe) are important candidates to understand mechanisms that drive the stripping of stripped-envelope (SE) supernova (SN) progenitors. While binary interactions and their high incidence are generally cited to favor them as Type IIb SN progenitors, this idea has not been tested using models covering a broad parameter space. In this paper, we use non-rotating single- and binary-star models at solar and low metallicities spanning a wide parameter space in primary mass, mass ratio, orbital period, and mass transfer efficiencies. We find that our single- and binary-star models contribute to roughly equal, however small, numbers of Type IIb SNe at solar metallicity. Binaries only dominate as progenitors at low metallicity. We also find that our models can account for less than half the observationally inferred rate for Type IIb SNe at solar metallicity, with computed rates ~<4% of core-collapse (CC) SNe. On the other hand, our models can account for the rates currently indicated by observations at low metallicity, with computed rates as high as 15% of CC SNe. However, this requires low mass transfer efficiencies (~<0.1) to prevent most progenitors from entering contact. We suggest that the stellar wind mass-loss rates at solar metallicity used in our models are too high. Lower mass-loss rates would widen the parameter space for binary Type IIb SNe at solar metallicity by allowing stars that initiate mass transfer earlier in their evolution to reach CC without getting fully stripped.
Is there a sign of new physics in beryllium transitions

We discuss the current status of the anomaly in beryllium-8 nuclear transitions recently reported in the angular distribution of internal conversion electron–positron pairs. We present a phenomenological analysis of the signal and review the models proposed to explain it, focusing on those involving a new light protophobic vector gauge boson. We also elaborate on the prospects of verifying the anomaly in present and future experiments.