cssi/SciSciGPT-SciSciNet huggingface dataset:
Functionalized TiO2 Nanotube-Based Electrochemical Biosensor for Rapid Detection of SARS-CoV-2

The COronaVIrus Disease (COVID-19) is a newly emerging viral disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Rapid increase in the number of COVID-19 cases worldwide led the WHO to declare a pandemic within a few months after the first case of infection. Due to the lack of a prophylactic measure to control the virus infection and spread, early diagnosis and quarantining of infected as well as the asymptomatic individuals are necessary for the containment of this pandemic. However, the current methods for SARS-CoV-2 diagnosis are expensive and time consuming, although some promising and inexpensive technologies are becoming available for emergency use. In this work, we report the synthesis of a cheap, yet highly sensitive, cobalt-functionalized TiO2 nanotubes (Co-TNTs)-based electrochemical sensor for rapid detection of SARS-CoV-2 through sensing the spike (receptor binding domain (RBD)) present on the surface of the virus. A simple, low-cost, and one-step electrochemical anodization route was used for synthesizing TNTs, followed by an incipient wetting method for cobalt functionalization of the TNTs platform, which was connected to a potentiostat for data collection. This sensor specifically detected the S-RBD protein of SARS-CoV-2 even at very low concentration (range of 14 to 1400 nM (nano molar)). Additionally, our sensor showed a linear response in the detection of viral protein over the concentration range. Thus, our Co-TNT sensor is highly effective in detecting SARS-CoV-2 S-RBD protein in approximately 30 s, which can be explored for developing a point of care diagnostics for rapid detection of SARS-CoV-2 in nasal secretions and saliva samples.
An auto-generated geometry-based discrete finite element model for damage evolution in composite laminates with arbitrary stacking sequence

Abstract Stiffness degradation and progressive failure of composite laminates are complex processes involving evolution and multi-mode interactions among fiber fractures, intra-ply matrix cracks and inter-ply delaminations. This paper presents a novel finite element model capable of explicitly treating such discrete failures in laminates of random layup. Matching of nodes is guaranteed at potential crack bifurcations to ensure correct displacement jumps near crack tips and explicit load transfer among cracks. The model is entirely geometry-based (no mesh prerequisite) with distinct segments assembled together using surface-based tie constraints, and thus requires no element partitioning or enrichment. Several numerical examples are included to demonstrate the model’s ability to generate results that are in qualitative and quantitative agreement with experimental observations on both damage evolution and tensile strength of specimens. The present model is believed unique in realizing simultaneous and accurate coupling of all three types of failures in laminates having arbitrary ply angles and layup.
Electrospun scaffold fiber orientation regulates endothelial cell and platelet properties associated with angiogenesis and hemocompatibility

Abstract Artificial scaffolds fabricated for tissue engineering and/or regenerative medicine applications typically aim to resemble specific properties of the innate extracellular matrix of a particular tissue. While there have been successes with this approach, it has become apparent that there are certain scaffold properties that are essential for tissue formation. Other, non-essential, properties, however, can aid in tissue formation but are not required for cell growth, maintenance and the formation of viable tissue engineered scaffolds. We aimed to investigate the role of electrospun scaffold topography on endothelial cell and platelet functions related to vascular growth throughout engineered scaffolds. We hypothesized that the growth and compatibility of cells throughout scaffolds would be enhanced as the scaffold topographical organization increased. To test this, we made use of a customized rotational electrospinning apparatus, which can increase the topographical organization of formed scaffolds. Scaffolds fabricated from cellulose acetate, chitosan and/or poly-caprolactone were tested. Our data illustrates that endothelial cells prefer to be cultured on scaffolds with increasing order and larger fiber diameters. In general, platelet activation, adhesion and aggregation responses were not a function of scaffold composition, however, platelets activation and adhesion was generally reduced in the presence of scaffolds, as compared to samples incubated without scaffolds. These results indicate that engineered scaffold properties should be fine-tuned for particular applications and overall, scaffolds may not need to resemble the extracellular matrix in all physical, mechanical and topographical properties to be successful in tissue engineering applications. Statement of Significance When designing engineered tissues, one must consider the physical properties of formed scaffolds as a means to control cell growth characteristics throughout the engineered scaffold. To date, there has been little agreement about which scaffold physical properties are essential for tissue growth. Further, it is essential for growing tissue to include patent vascular networks and here we optimized a method to control the organization of fibers within electrospun scaffolds and promote vascular network growth throughout those scaffolds. Importantly, with increasing fiber organization, scaffolds performed better for vascular tissue engineering applications, in terms of endothelial cell and platelet performance.
Quantifying the Sensitivity to Errors in Analog Quantum Simulation

A framework to predict whether a noisy quantum simulation is reliable is presented and experimentally validated.
Homomorphisms between diffeomorphism groups

For be one-dimensional? We show that the answer is yes, even under more general conditions. Several lemmas on subgroups of diffeomorphism groups are of independent interest, including results on commuting subgroups and flows.
Projective product spaces

Let n = (n 1 ,…n r ). The quotient space P n := S n1 ×…× S nr / (x ~ −x) is what we call a projective product space. We determine the integral cohomology ring H* (P n ) and the action of the Steenrod algebra on H* (P n ; ℤ 2 ). We give a splitting of Σ P n in terms of stunted real projective spaces, and determine when S ni is a product factor of P n . We relate the immersion dimension and span of P n to the much-studied sectioning question for multiples of the Hopf bundle over real projective spaces. We show that the immersion dimension of P n depends only on min(n i ), ∑ n i , and r, and determine its precise value unless all n i ≥ 10. We also determine exactly when P n is parallelizable.
From Robotic Process Automation to Intelligent Process Automation: Emerging Trends

In this survey, we study how recent advances in machine intelligence are disrupting the world of business processes. Over the last decade, there has been steady progress towards the automation of business processes under the umbrella of “robotic process automation” (RPA). However, we are currently at an inflection point in this evolution, as a new paradigm called “Intelligent Process Automation” (IPA) emerges, bringing machine learning (ML) and artificial intelligence (AI) technologies to bear in order to improve business process outcomes. The purpose of this paper is to provide a survey of this emerging theme and identify key open research challenges at the intersection of AI and business processes. We hope that this emerging theme will spark engaging conversations at the RPA Forum.
SUPPORT POINTS OF LOCALLY OPTIMAL DESIGNS FOR NONLINEAR MODELS WITH TWO PARAMETERS

We propose a new approach for identifying the support points of a locally optimal design when the model is a nonlinear model. In contrast to the commonly used geometric approach, we use an approach based on algebraic tools. Considerations are restricted to models with two parameters, and the general results are applied to often used special cases, including logistic, probit, double exponential and double reciprocal models for binary data, a loglinear Poisson regression model for count data, and the Michaelis-Menten model. The approach, which is also of value for multi-stage experiments, works both with constrained and unconstrained design regions and is relatively easy to implement.
Detecting and Receiving Phase-Modulated Signals With a Rydberg Atom-Based Receiver

The recent developments of Rydberg atom-based sensors with the ability to measure phase have made it possible to receive digital phase-modulated signals. In this letter, we demonstrate the reception of binary phase-shift keying, quadrature phase-shift keying, and quadrature amplitude modulation signals with an atom-based receiver. We present measured values of error vector magnitude as a function of symbol rate for various modulation schemes and discuss the bandwidth of a Rydberg atom-based receiver system. The results show that we can now interrogate ensembles of atoms to such extent that we can use them to receive data from a phase-modulated communication signal.
The nature of the gravitational vacuum

The vacuum must contain virtual fluctuations of black hole microstates for each mass M. We observe that the expected suppression for M ≫ mp is counteracted by the large number Exp[Sbek] of such sta...
Holographic inequalities and entanglement of purification

We study the conjectured holographic duality between entanglement of purification and the entanglement wedge cross-section. We generalize both quantities and prove several information theoretic inequalities involving them. These include upper bounds on conditional mutual information and tripartite information, as well as a lower bound for tripartite information. These inequalities are proven both holographically and for general quantum states. In addition, we use the cyclic entropy inequalities to derive a new holographic inequality for the entanglement wedge cross-section, and provide numerical evidence that the corresponding inequality for the entanglement of purification may be true in general. Finally, we use intuition from bit threads to extend the conjecture to holographic duals of suboptimal purifications.
THE MID-IR CONTRIBUTION OF DUST-ENSHROUDED STARS IN SIX NEARBY GALAXIES

We measure the integrated contributions of dusty asymptotic giant branch (AGB) stars and other luminous red mid-IR sources to the mid-IR luminosities of six galaxies (M81, NGC 2403, NGC 300, M33, and the Magellanic Clouds). We find the dusty AGB stars whose mid-IR fluxes are dominated by dust rather than photospheric emission contribute from 0.6% (M81) to 5.6% (SMC) of the 3.6 μm flux and 1.0% (M81) to 10.1% (SMC) of the 4.5 μm flux. We find a trend of decreasing AGB contribution with increasing galaxy metallicity, luminosity, and mass, and decreasing specific star formation rate (SSFR). However, these galaxy properties are strongly correlated in our sample and the simplest explanation of the trend is galaxy metallicity. Bright, red sources other than dusty AGB stars represent a smaller fraction of the luminosity, ~1.2% at 3.6 μm, however, their dust is likely cooler and their contributions are likely larger at longer wavelengths. Excluding the SMC, the contribution from these red sources correlates with the SSFR as we would expect for massive stars. In total, after correcting for dust emission at other wavelengths, the dust around AGB stars radiates 0.1%-0.8% of the bolometric luminosities of the galaxies. Thus, hot dust emission from AGB and other luminous dusty stars represent a small fraction of the total luminosities of the galaxies but a significant fraction of their mid-IR emissions.
Good Views of the Galaxy

Fitting Galactic structure models to star counts only provides useful information about the Galaxy in some directions. In this paper, we investigate the use of χ2 goodness-of-fit tests to discriminate between degenerate Galactic structure models and the implications of this technique for the Galactic spheroid and thick-disk components. The axis ratio of the Galactic spheroid and the normalization of spheroid stars with respect to disk stars introduce a degenerate effect which means that Galactic structure models with certain combinations of these parameters are indistinguishable from each other in most directions. We present an analysis of the optimal directions in which these degeneracies can be lifted. Poisson and magnitude errors are taken into account, and an attempt is made to place an upper limit on the systematic error due to separation of spheroid stars from thick/old disk stars. We find that the magnitude range 20 < V < 21 is the best for lifting most degeneracies, and present the optimal combinations of directions using which this can be achieved. We also give directions in which the signature of the presence of a Galactic thick disk can be most readily identified, and the directions in which contamination from a thick disk can be minimized. It is hoped that forthcoming data from large-scale sky surveys would reveal much about the structure of our Galaxy using star count techniques.
Planar graphs that need four pages

Abstract We show that there are planar graphs that require four pages in any book embedding.
Six Line Configurations and String Dualities

We study the family of K3 surfaces of Picard rank sixteen associated with the double cover of the projective plane branched along the union of six lines, and the family of its Van Geemen–Sarti partners, i.e., K3 surfaces with special Nikulin involutions, such that quotienting by the involution and blowing up recovers the former. We prove that the family of Van Geemen–Sarti partners is a four-parameter family of K3 surfaces with $${H \oplus E_7(-1) \oplus E_7(-1)}$$ lattice polarization. We describe explicit Weierstrass models on both families using even modular forms on the bounded symmetric domain of type IV. We also show that our construction provides a geometric interpretation, called geometric two-isogeny, for the F-theory/heterotic string duality in eight dimensions.
Single-index model-assisted estimation in survey sampling

A model-assisted semiparametric method of estimating finite-population totals is investigated to improve the precision of survey estimators by incorporating multivariate auxiliary information. The proposed superpopulation model is a single-index model (SIM) which has proven to be a simple and efficient semiparametric tool in multivariate regression. A class of estimators based on polynomial spline regression is proposed. These estimators are robust against deviation from SIMs. Under standard design conditions, the proposed estimators are asymptotically design-unbiased, consistent and asymptotically normal. An iterative optimisation routine is provided that is sufficiently fast for users to analyze large and complex survey data within seconds. The proposed method has been applied to simulated datasets and MU281 dataset, which have provided strong evidence that corroborates with the asymptotic theory.
Hierarchy of universal entanglement in 2D measurement-based quantum computation

Measurement-based quantum computation (MQC) is a paradigm for studying quantum computation using many-body entanglement and single-qubit measurements. Although MQC has inspired wide-ranging discoveries throughout quantum information, our understanding of the general principles underlying MQC seems to be biased by its historical reliance upon the archetypal 2D cluster state. Here we utilise recent advances in the subject of symmetry-protected topological order (SPTO) to introduce a novel MQC resource state, whose physical and computational behaviour differs fundamentally from that of the cluster state. We show that, in sharp contrast to the cluster state, our state enables universal quantum computation using only measurements of single-qubit Pauli X, Y, and Z operators. This novel computational feature is related to the ‘genuine’ 2D SPTO possessed by our state, and which is absent in the cluster state. Our concrete connection between the latent computational complexity of many-body systems and macroscopic quantum orders may find applications in quantum many-body simulation for benchmarking classically intractable complexity. Researchers have discovered a quantum state of matter with advantageous properties for quantum computing. Jacob Miller and Akimasa Miyake from the University of New Mexico in the United States studied the physical states that form the basis for many quantum computing systems. Quantum states can require complex operations to achieve the desired computational task. In searching for a scalable implementation, Miller and Miyake focused on a class of two-dimensional states of topological matter with certain symmetries. These symmetries not only give a natural means of encoding quantum information, but also help to protect the integrity of the state against undesirable decay processes. Furthermore, the encoded information can be processed with physical measurements more easily, making the use of symmetry-protected states an attractive alternative to conventional realizations of quantum computing.
A Kernel of Truth: Determining Rumor Veracity on Twitter by Diffusion Pattern Alone

Recent work in the domain of misinformation detection has leveraged rich signals in the text and user identities associated with content on social media. But text can be strategically manipulated and accounts reopened under different aliases, suggesting that these approaches are inherently brittle. In this work, we investigate an alternative modality that is naturally robust: the pattern in which information propagates. Can the veracity of an unverified rumor spreading online be discerned solely on the basis of its pattern of diffusion through the social network? Using graph kernels to extract complex topological information from Twitter cascade structures, we train accurate predictive models that are blind to language, user identities, and time, demonstrating for the first time that such “sanitized” diffusion patterns are highly informative of veracity. Our results indicate that, with proper aggregation, the collective sharing pattern of the crowd may reveal powerful signals of rumor truth or falsehood, even in the early stages of propagation.
Asymptotic structure and coarse Lipschitz geometry of Banach spaces

In this paper, we study the coarse Lipschitz geometry of Banach spaces with several asymptotic properties. Specifically, we look at asymptotically uniformly smoothness and convexity, and several distinct Banach-Saks-like properties. Among other results, we characterize the Banach spaces which are either coarsely or uniformly homeomorphic to $T^{p_1}\oplus \ldots \oplus T^{p_n}$, where each $T^{p_j}$ denotes the $p_j$-convexification of the Tsirelson space, for $p_1,\ldots,p_n\in (1,\ldots, \infty)$, and $2\not\in\{p_1,\ldots ,p_n\}$. We obtain applications to the coarse Lipschitz geometry of the $p$-convexifications of the Schlumprecht space, and some hereditarily indecomposable Banach spaces. We also obtain some new results on the linear theory of Banach spaces.
FORMATION OF GIANT PLANETS BY DISK INSTABILITY ON WIDE ORBITS AROUND PROTOSTARS WITH VARIED MASSES

Doppler surveys have shown that more massive stars have significantly higher frequencies of giant planets inside ~3 AU than lower mass stars, consistent with giant planet formation by core accretion. Direct imaging searches have begun to discover significant numbers of giant planet candidates around stars with masses of ~1 M ☉ to ~2 M ☉ at orbital distances of ~20 AU to ~120 AU. Given the inability of core accretion to form giant planets at such large distances, gravitational instabilities of the gas disk leading to clump formation have been suggested as the more likely formation mechanism. Here, we present five new models of the evolution of disks with inner radii of 20 AU and outer radii of 60 AU, for central protostars with masses of 0.1, 0.5, 1.0, 1.5, and 2.0 M ☉, in order to assess the likelihood of planet formation on wide orbits around stars with varied masses. The disk masses range from 0.028 M ☉ to 0.21 M ☉, with initial Toomre Q stability values ranging from 1.1 in the inner disks to ~1.6 in the outer disks. These five models show that disk instability is capable of forming clumps on timescales of ~103 yr that, if they survive for longer times, could form giant planets initially on orbits with semimajor axes of ~30 AU to ~70 AU and eccentricities of ~0 to ~0.35, with initial masses of ~1 M Jup to ~5 M Jup, around solar-type stars, with more protoplanets forming as the mass of the protostar (and protoplanetary disk) is increased. In particular, disk instability appears to be a likely formation mechanism for the HR 8799 gas giant planetary system.
Ultra-low-energy non-volatile straintronic computing using single multiferroic composites

The primary impediment to continued downscaling of traditional charge-based electronic devices in accordance with Moore's law is the excessive energy dissipation that takes place in the device during switching of bits. One very promising solution is to utilize multiferroic heterostructures, comprised of a single-domain magnetostrictive nanomagnet strain-coupled to a piezoelectric layer, in which the magnetization can be switched between its two stable states while dissipating minuscule amount of energy. However, no efficient and viable means of computing is proposed so far. Here we show that such single multiferroic composites can act as universal logic gates for computing purposes, which we demonstrate by solving the stochastic Landau-Lifshitz-Gilbert equation of magnetization dynamics in the presence of room-temperature thermal fluctuations. The proposed concept can overwhelmingly simplify the design of large-scale circuits and portend a highly dense yet an ultra-low-energy computing paradigm for our fu...
Rapidity Correlation Structures from Causal Hydrodynamics

Viscous diffusion can broaden the rapidity dependence of two-particle transverse momentum fluctuations. Surprisingly, measurements at RHIC by the STAR collaboration demonstrate that this broadening is accompanied by the appearance of unanticipated structure in the rapidity distribution of these fluctuations in the most central collisions. Although a first order classical Navier-Stokes theory can roughly explain the rapidity broadening, it cannot explain the additional structure. We propose that the rapidity structure can be explained using the second order causal Israel-Stewart hydrodynamics with stochastic noise.
Robust mode space approach for atomistic modeling of realistically large nanowire transistors

Nanoelectronic transistors have reached 3D length scales in which the number of atoms is countable. Truly atomistic device representations are needed to capture the essential functionalities of the devices. Atomistic quantum transport simulations of realistically extended devices are, however, computationally very demanding. The widely used mode space (MS) approach can significantly reduce the numerical cost, but a good MS basis is usually very hard to obtain for atomistic full-band models. In this work, a robust and parallel algorithm is developed to optimize the MS basis for atomistic nanowires. This enables engineering-level, reliable tight binding non-equilibrium Green's function simulation of nanowire metal-oxide-semiconductor field-effect transistor (MOSFET) with a realistic cross section of 10 nm × 10 nm using a small computer cluster. This approach is applied to compare the performance of InGaAs and Si nanowire n-type MOSFETs (nMOSFETs) with various channel lengths and cross sections. Simulation r...
Light Higgsino Dark Matter in the MSSM on D-branes

When supersymmetry (SUSY) breaking is dominated by the complex structure moduli and the universal dilaton, a subset of the SUSY parameter space in a realistic minimal supersymmetric standard model constructed from intersecting/magnetized D-branes are universal, similar to the effective minimal supergravity (mSUGRA)/constrained minimal supersymmetric standard model (CMSSM) parameter space with a universal scalar mass m0, a universal gaugino mass and with the universal trilinear term fixed to be minus the gaugino mass, A0 = ?m1/2. More generally, the scalar mass-squared terms for sfermions are split about the Higgs mass-squared terms, and , for generic values of the K?hler moduli. The scalar masses are universal only for a specific choice of the K?hler moduli. The hyperbolic branch/focus point (HB/FP) regions of this parameter space are present for both and . Interestingly, it is known that FPs may be realized with any boundary condition of the form with x an arbitrary constant, the same form as those in this model. Thus, we should expect to obtain the same set of FPs in the model regardless of the choice of K?hler moduli. It should be emphasized that the more general choice of K?hler moduli goes beyond (mSUGRA/CMSSM). It is shown that there exists superpartner spectra with a light Higgsino-like LSP with 230?350 GeV and a Higgs mass in the range 124?126 GeV, and which satisfy most standard experimental constraints. Consequently, viable spectra with low electroweak fine-tuning between 3%?7% may be obtained. The spin-independent direct-detection crosssections are in range of future experiments such as XENON?1 T and super CDMS, while the relic density is smaller than the WMAP and Planck bounds by roughly a factor of ten, implying that the LSP is sub-dominant component of dark matter. In addition, most of the spectra are consistent with constraints from indirect-detection experiments.
What You Don't Know Can't Help You: Pension Knowledge and Retirement Decision-Making

Abstract This paper provides an answer to an important empirical puzzle in the retirement literature: while most people know little about their own pension plans, retirement behavior is strongly affected by pension incentives. We combine administrative and self-reported pension data to measure the retirement response to actual and perceived financial incentives and document an important role for self-reported pension data in determining retirement behavior. Well-informed individuals are far more responsive to pension incentives than the average individual. Ill-informed individuals seem to respond systematically to their own misperceptions of pension incentives.
Nonlinear light behaviors near phase transition in non-parity-time-symmetric complex waveguides

Many classes of non-parity-time (PT)-symmetric waveguides with arbitrary gain and loss distributions still possess all-real linear spectrum or exhibit phase transition. In this Letter, nonlinear light behaviors in these complex waveguides are probed analytically near a phase transition. Using multi-scale perturbation methods, a nonlinear ordinary differential equation (ODE) is derived for the light's amplitude evolution. This ODE predicts that a single class of these non-PT-symmetric waveguides supports soliton families and amplitude-oscillating solutions both above and below linear phase transition, in close analogy with PT-symmetric systems. For the other classes of waveguides, the light's intensity always amplifies under the effect of nonlinearity, even if the waveguide is below the linear phase transition. These analytical predictions are confirmed by direct computations of the full system.
Bayesian nonparametric cross-study validation of prediction methods

We consider comparisons of statistical learning algorithms using multiple data sets, via leave-one-in cross-study validation: each of the algorithms is trained on one data set; the resulting model is then validated on each remaining data set. This poses two statistical challenges that need to be addressed simultaneously. The first is the assessment of study heterogeneity, with the aim of identifying a subset of studies within which algorithm comparisons can be reliably carried out. The second is the comparison of algorithms using the ensemble of data sets. We address both problems by integrating clustering and model comparison. We formulate a Bayesian model for the array of cross-study validation statistics, which defines clusters of studies with similar properties and provides the basis for meaningful algorithm comparison in the presence of study heterogeneity. We illustrate our approach through simulations involving studies with varying severity of systematic errors, and in the context of medical prognosis for patients diagnosed with cancer, using high-throughput measurements of the transcriptional activity of the tumor’s genes.
Morse matchings on polytopes

We show how to construct homology bases for certain CW complexes in terms of discrete Morse theory and cellular homology. We apply this technique to study certain subcomplexes of the half cube polytope studied in previous works. This involves constructing explicit complete acyclic Morse matchings on the face lattice of the half cube; this procedure may be of independent interest for other highly symmetric polytopes.
Enabling privacy-preserving auctions in big data

We study how to enable auctions in the big data context to solve many upcoming data-based decision problems in the near future. We consider the characteristics of the big data including, but not limited to, velocity, volume, variety, and veracity, and we believe any auction mechanism design in the future should take the following factors into consideration: 1) generality (variety); 2) efficiency and scalability (velocity and volume); 3) truthfulness and verifiability (veracity). In this paper, we propose a privacy-preserving construction for auction mechanism design in the big data, which prevents adversaries from learning unnecessary information except those implied in the valid output of the auction. More specifically, we considered one of the most general form of the auction (to deal with the variety), and greatly improved the the efficiency and scalability by approximating the NP-hard problems and avoiding the design based on garbled circuits (to deal with velocity and volume), and finally prevented stakeholders from lying to each other for their own benefit (to deal with the veracity). The comparison with peer work shows that we greatly improved the asymptotic performance of peer works' overhead from the exponential growth to a linear growth and from linear growth to a logarithmic growth, which greatly contributes to the scalability of our mechanism.
Maximal contact and symplectic structures

We introduce a procedure for gluing Weinstein domains along Weinstein subdomains. By gluing along flexible subdomains, we show that any finite collection of high-dimensional Weinstein domains with the same topology are Weinstein subdomains of a `maximal' Weinstein domain also with the same topology. As an application, we produce exotic cotangent bundles containing many closed regular Lagrangians that are formally Lagrangian isotopic but not Hamiltonian isotopic and also give a new construction of exotic Weinstein structures on Euclidean space. We describe a similar construction in the contact setting which we use to produce `maximal' contact structures and extend several existing results in low-dimensional contact geometry to high-dimensions. We prove that all contact manifolds have symplectic caps, introduce a general procedure for producing contact manifolds with many Weinstein fillings, and give a new proof of the existence of codimension two contact embeddings.
Shuttling a single charge across a one-dimensional array of silicon quantum dots

Significant advances have been made towards fault-tolerant operation of silicon spin qubits, with single qubit fidelities exceeding 99.9%, several demonstrations of two-qubit gates based on exchange coupling, and the achievement of coherent single spin-photon coupling. Coupling arbitrary pairs of spatially separated qubits in a quantum register poses a significant challenge as most qubit systems are constrained to two dimensions with nearest neighbor connectivity. For spins in silicon, new methods for quantum state transfer should be developed to achieve connectivity beyond nearest-neighbor exchange. Here we demonstrate shuttling of a single electron across a linear array of nine series-coupled silicon quantum dots in ~50 ns via a series of pairwise interdot charge transfers. By constructing more complex pulse sequences we perform parallel shuttling of two and three electrons at a time through the array. These experiments demonstrate a scalable approach to physically transporting single electrons across large silicon quantum dot arrays. As quantum computers grow in complexity the challenge of moving information between physically separated qubits becomes more pressing. Mills et al. demonstrate transfer of single electrons across an array of nine silicon quantum dots three orders of magnitude faster than spin qubit decoherence times.
Calibration of tests for time dilation in GRB pulse structures

If gamma-ray bursts are at cosmological distances, then not only their constituent pulses but also the intervals between pulses should be time-dilated. Unlike time-dilation measures of pulse emission, intervals would appear to require less "K-correction" for redshift of narrower temporal structure from higher energy into the band of observation. However, stretching of pulse intervals is intrinsically difficult to measure without incurring a timescale-dependent bias since, as time profiles are stretched, more structure can appear at the limit of resolution. This problem is compounded in dimmer bursts since identification of significant structures is problematic. We have attempted to minimize brightness bias problems by equalizing the signal-to-noise level of all bursts. Then, analyzing wavelet-denoised profiles binned to several resolutions, we identify significant (3 - 4 sigma) fluctuations between pulse structures and interjacent valleys. When bursts are ranked by peak flux, an interval time-dilation signature is evident, but its measure is dependent upon choice of temporal resolution. This result appears to tentatively and qualitatively confirm the work of Davis, who found such a signature using a pulse fitting approach.
Improvements on the stability and operation of a magnetron H- ion source

The magnetron ${\mathrm{H}}^{\ensuremath{-}}$ ion sources developed in the 1970s currently in operation at Fermilab provide beam to the rest of the accelerator complex. A series of modifications to these sources have been tested in a dedicated off-line test stand with the aim of improving different operational issues. The solenoid type gas valve was tested as an alternative to the piezoelectric gas valve in order to avoid its temperature dependence. A new cesium oven was designed and tested in order to avoid glass pieces that were present with the previous oven, improve thermal insulation and fine-tune its temperature. A current-regulated arc modulator was developed to run the ion source at a constant arc current, providing very stable beam outputs during operations. In order to reduce beam noise, the addition of small amounts of ${\mathrm{N}}_{2}$ gas was explored, as well as testing different cathode shapes with increasing plasma volume. This paper summarizes the studies and modifications done in the source over the past three years with the aim of improving its stability, reliability and overall performance.
The quantum hydrodynamics of the Sutherland model

We show that the form of the chiral condition found by Abanov et al in the quantum hydrodynamics of the Sutherland model arises because there are two distinct inner products with respect to which the chiral Hamiltonian is Hermitian, but only one with respect to which the full, non-chiral, Hamiltonian is Hermitian.
Self-averaging scaling limits of two-frequency Wigner distribution for random paraxial waves

Two-frequency Wigner distribution is introduced to capture the asymptotic behaviour of the space–frequency correlation of paraxial waves in the radiative transfer limits. The scaling limits give rises to deterministic transport-like equations. Depending on the ratio of the wavelength to the correlation length the limiting equation is either a Boltzmann-like integral equation or a Fokker–Planck-like differential equation in the phase space. The solutions to these equations have a probabilistic representation which can be simulated by Monte Carlo method. When the medium fluctuates more rapidly in the longitudinal direction, the corresponding Fokker–Planck-like equation can be solved exactly.
Periodically driven adiabatic bipolarons

Small lattice bipolarons driven by external harmonic fields are considered in the adiabatic approximation. Resonant excitation of ions modulates the trapping potential and promotes hole transfer between neighboring atomic layers. It leads to a dramatic decrease of the apparent bipolaron mass compared to the undriven case. This effect offers an explanation for dynamic stabilization of superconductivity at high temperatures recently observed in layered cuprates.
Integral canonical models for Spin Shimura varieties

We construct regular integral canonical models for Shimura varieties attached to Spin and orthogonal groups at (possibly ramified) primes . Work of Vasiu–Zink then shows that the classical Kuga–Satake construction extends over the integral models and that the integral models we construct are canonical in a very precise sense. Our results have applications to the Tate conjecture for K3 surfaces, as well as to Kudla’s program of relating intersection numbers of special cycles on orthogonal Shimura varieties to Fourier coefficients of modular forms.
Dynamics of Abelian Vortices Without Common Zeros in the Adiabatic Limit

On a smooth line bundle L over a compact Kahler Riemann surface Σ, we study the family of vortex equations with a parameter s. For each \({s \in [1,\infty]}\) , we invoke techniques in Bradlow (Commun Math Phys 135:1–17, 1990) by turning the s-vortex equation into an s-dependent elliptic partial differential equation, studied in Kazdan and Warner (Ann Math 2:14–47, 1978), providing an explicit moduli space description of the space of gauge classes of solutions. We are particularly interested in the bijective correspondence between the open subset of vortices without common zeros and the space of holomorphic maps. For each s, the correspondence is uniquely determined by a smooth function us on Σ, and we confirm its convergent behaviors as \({s \to \infty}\) . Our results prove a conjecture posed by Baptista in Baptista (Nucl Phys B 844:308–333, 2010), stating that the s-dependent correspondence is an isometry between the open subsets when s = ∞, with L2 metrics appropriately defined.
Formation of self-organized anode patterns in arc discharge simulations

Pattern formation and self-organization are phenomena commonly observed experimentally in diverse types of plasma systems, including atmospheric-pressure electric arc discharges. However, numerical simulations reproducing anode pattern formation in arc discharges have proven exceedingly elusive. Time-dependent three-dimensional thermodynamic non-equilibrium simulations reveal the spontaneous formation of self-organized patterns of anode attachment spots in the free-burning arc, a canonical thermal plasma flow established by a constant dc current between an axi-symmetric electrode configuration in the absence of external forcing. The number of spots, their size and distribution within the pattern depend on the applied total current and on the resolution of the spatial discretization, whereas the main properties of the plasma flow, such as maximum temperatures, velocity and voltage drop, depend only on the former. The sensibility of the solution to the spatial discretization stresses the computational requirements for comprehensive arc discharge simulations. The obtained anode patterns qualitatively agree with experimental observations and confirm that the spots originate at the fringes of the arc–anode attachment. The results imply that heavy-species–electron energy equilibration, in addition to thermal instability, has a dominant role in the formation of anode spots in arc discharges.
Density matrix equation for a bathed small system and its application to molecular magnets

The technique of density matrix equation (DME) for a small system interacting with a bath is explained in detail. Special attention is given to the nonsecular DME that is needed in the vicinity of overdamped tunnelling resonances in molecular magnets (MM). The relaxation terms of the DME for MM are represented in the universal form that does not employ any unknown spin-lattice coupling constants and absorbs the information about the spin Hamiltonian in the exact basis states and transition frequencies. This makes adding new types of anisotropy easy and error-free. The Mathematica code is available from the author.
A Catalog of Stellar Evolution Profiles and the Effects of Variable Composition on Habitable Systems

We present stellar evolution models for 0.5–1.2 at scaled metallicities of 0.1–1.5 Z and O/Fe values of 0.44–2.28 O/Fe. The time-dependent evolution of habitable zone (HZ) boundaries is calculated for each stellar evolution track based on stellar mass, effective temperature, and luminosity parameterizations. The rate of change of stellar surface quantities and the surrounding HZ position are strong functions of all three quantities explored. The range of orbits that remain continuously habitable, or habitable for at least 2 Gyr, are provided. The results show that the detailed chemical characterization of exoplanet host stars and a consideration of their evolutionary history are necessary to assess the likelihood that a planet found in the instantaneous HZ has had sufficient time to develop a biosphere capable of producing detectable biosignatures. This model grid is designed for use by the astrobiology and exoplanet communities to efficiently characterize the time evolution of host stars and their HZs for planetary candidates of interest.
Holography, singularities on orbifolds and 4D N = 2 SQCD

Type-II string theory compactified on a Calabi-Yau manifold, with a singularity modeled by a hypersurface in an orbifold, is considered. In the limit of vanishing string coupling, one expects a non gravitational theory concentrated at the singularity. It is proposed that this theory is holographicly dual to a family of ``non-critical'' superstring vacua, generalizing a previous proposal for hypersurfaces in flat space. It is argued that a class of such singularities is relevant for the study of non-trivial IR fixed points that appear in the moduli space of four-dimensional N = 2 SQCD: SU(Nc) gauge theory with matter in the fundamental representation. This includes the origin in the moduli space of the SU(Nc) gauge theory with Nf = 2Nc fundamentals. The 4D IR fixed points are studied using the anti-holographic description and the results agree with information available from gauge theory.
A stronger soft-covering lemma and applications

Wyner's soft-covering lemma is a valuable tool for achievability proofs of information theoretic security, resolvability, channel synthesis, and source coding. The result herein sharpens the claim of soft-covering by moving away from an expected value analysis. Instead, a random codebook is shown to achieve the soft-covering phenomenon with high probability. The probability of failure is doubly-exponentially small in the block-length, enabling more powerful applications through the union bound.
Sensitivity to switching rates in stochastically switched odes

We consider a stochastic process driven by a linear ordinary differential equation whose right-hand side switches at exponential times between a collection of different matrices. We construct planar examples that switch between two matrices where the individual matrices and the average of the two matrices are all Hurwitz (all eigenvalues have strictly negative real part), but nonetheless the process goes to infinity at large time for certain values of the switching rate. We further construct examples in higher dimensions where again the two individual matrices and their averages are all Hurwitz, but the process has arbitrarily many transitions between going to zero and going to infinity at large time as the switching rate varies. In order to construct these examples, we first prove in general that if each of the individual matrices is Hurwitz, then the process goes to zero at large time for sufficiently slow switching rate and if the average matrix is Hurwitz, then the process goes to zero at large time for sufficiently fast switching rate. We also give simple conditions that ensure the process goes to zero at large time for all switching rates.
SDSS J184037.78+642312.3: The First Pulsating Extremely Low Mass White Dwarf

We report the discovery of the first pulsating extremely low mass (ELM) white dwarf (WD), SDSS J184037.78+642312.3 (hereafter J1840). This DA (hydrogen-atmosphere) WD is by far the coolest and the lowest-mass pulsating WD, with T eff = 9100 ± 170 K and log g = 6.22 ± 0.06, which corresponds to a mass of ~0.17 M ☉. This low-mass pulsating WD greatly extends the DAV (or ZZ Ceti) instability strip, effectively bridging the log g gap between WDs and main-sequence stars. We detect high-amplitude variability in J1840 on timescales exceeding 4000 s, with a non-sinusoidal pulse shape. Our observations also suggest that the variability is multi-periodic. The star is in a 4.6 hr binary with another compact object, most likely another WD. Future, more extensive time-series photometry of this ELM WD offers the first opportunity to probe the interior of a low-mass, presumably He-core WD using the tools of asteroseismology.
Unsteady aerodynamics and vortex-sheet formation of a two-dimensional airfoil

Unsteady inviscid flow models of wings and airfoils have been developed to study the aerodynamics of natural and man-made flyers. Vortex methods have been extensively applied to reduce the dimensionality of these aerodynamic models, based on the proper estimation of the strength and distribution of the vortices in the wake. In such modelling approaches, one of the most fundamental questions is how the vortex sheets are generated and released from sharp edges. To determine the formation of the trailing-edge vortex sheet, the classical steady Kutta condition can be extended to unsteady situations by realizing that a flow cannot turn abruptly around a sharp edge. This condition can be readily applied to a flat plate or an airfoil with cusped trailing edge since the direction of the forming vortex sheet is known to be tangential to the trailing edge. However, for a finite-angle trailing edge, or in the case of flow separation away from a sharp corner, the direction of the forming vortex sheet is ambiguous. To remove any ad hoc implementation, the unsteady Kutta condition, the conservation of circulation as well as the conservation laws of mass and momentum are coupled to analytically solve for the angle, strength and relative velocity of the trailing-edge vortex sheet. The two-dimensional aerodynamic model together with the proposed vortex-sheet formation condition is verified by comparing flow structures and force calculations with experimental results for several airfoil motions in steady and unsteady background flows.
Write Channel Model for Bit-Patterned Media Recording

We propose a new write channel model for bit-patterned media recording that reflects the data dependence of write synchronization errors. It is shown that this model accommodates both substitution-like errors and insertion-deletion errors whose statistics are determined by an underlying channel state process. We study information theoretic properties of the write channel model, including the capacity, symmetric information rate, Markov-1 rate, and the zero-error capacity.