cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Bilevel optimization in flow networks: A message-passing approach
Creators: name: Li, Bo
name: Saad, David
name: Yeung, Chi Ho
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optimization and Control (math.OC)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: Optimizing embedded systems, where the optimization of one depends on the state of another, is a formidable computational and algorithmic challenge, that is ubiquitous in real world systems. We study flow networks, where bilevel optimization is relevant to traffic planning, network control and design, and where flows are governed by an optimization requirement subject to the network parameters. We employ message-passing algorithms in flow networks with sparsely coupled structures to adapt network parameters that govern the network flows, in order to optimize a global objective. We demonstrate the effectiveness and efficiency of the approach on randomly generated graphs.
Disaggregation of Remotely Sensed Soil Moisture in Heterogeneous Landscapes using Holistic Structure based Models
Creators: name: Chakrabarti, Subit
name: Judge, Jasmeet
name: Rangarajan, Anand
name: Ranka, Sanjay
Publisher: name: arXiv
Year: 2015
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences
subject: 68

description: In this study, a novel machine learning algorithm is presented for disaggregation of satellite soil moisture (SM) based on self-regularized regressive models (SRRM) using high-resolution correlated information from auxiliary sources. It includes regularized clustering that assigns soft memberships to each pixel at fine-scale followed by a kernel regression that computes the value of the desired variable at all pixels. Coarse-scale remotely sensed SM were disaggregated from 10km to 1km using land cover, precipitation, land surface temperature, leaf area index, and in-situ observations of SM. This algorithm was evaluated using multi-scale synthetic observations in NC Florida for heterogeneous agricultural land covers. It was found that the root mean square error (RMSE) for 96% of the pixels was less than 0.02 $m^3/m^3$. The clusters generated represented the data well and reduced the RMSE by upto 40% during periods of high heterogeneity in land-cover and meteorological conditions. The Kullback Leibler divergence (KLD) between the true SM and the disaggregated estimates is close to 0, for both vegetated and baresoil landcovers. The disaggregated estimates were compared to those generated by the Principle of Relevant Information (PRI) method. The RMSE for the PRI disaggregated estimates is higher than the RMSE for the SRRM on each day of the season. The KLD of the disaggregated estimates generated by the SRRM is at least four orders of magnitude lower than those for the PRI disaggregated estimates, while the computational time needed was reduced by three times. The results indicate that the SRRM can be used for disaggregating SM with complex non-linear correlations on a grid with high accuracy.
description: 28 pages, 14 figures, submitted to IEEE Transactions on Geoscience and Remote Sensing
Laboratory model of electrovortex flow with thermal gradients, for liquid metal batteries
Creators: name: Cheng, Jonathan S
name: Wang, Bitong
name: Mohammad, Ibrahim
name: Forer, Jarod M
name: Kelley, Douglas H
Publisher: name: arXiv
Year: 2021
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We present a novel laboratory setup for studying the fluid dynamics in liquid metal batteries (LMBs). LMBs are a promising technology suited for grid-scale energy storage, but flows remain a confounding factor in determining their viability. Two important drivers of flow are thermal gradients, caused by internal heating during operation, and electrovortex flow (EVF), induced by diverging current densities. Our setup explores thermal gradients and electrovortex flow separately and in combination in a cylindrical layer of liquid gallium, simulating the behavior in a single layer of an LMB. In this work, we discuss the design principles underlying our choices of materials, thermal control, and current control. We also detail our diagnostic tools - thermocouple measurements for temperature and Ultrasonic Doppler Velocimetry (UDV) probes for velocities - and the design principles which go into choosing their placement on the setup. We also include a discussion of our post-processing tools for quantifying and visualizing the flow. Finally, we validate convection and EVF in our setup: we show that scaling relationships between the nondimensional parameters produced by our data agree well with theory and previous studies.
description: 13 pages, 9 figures
Treatment for ADHD: Is More Complex Treatment Cost-Effective for More Complex Cases?
Creators: name: Jensen, Peter S.
name: Wigal, Timothy
name: Pelham, William E.
name: Arnold, L. Eugene
name: Swanson, James M.
name: Foster, E. Michael
name: Hechtman, Lily
name: Schlander, Michael
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2007

description: To determine the cost-effectiveness of three alternative high-quality treatments for attention deficit hyperactivity disorder (ADHD) relative to community care (CC) and to determine whether cost-effectiveness varies with the presence of comorbid disorders.
An Empirical Taxonomy of Hospital Governing Board Roles
Creators: name: Wang, Virginia
name: Lee, Shoou-Yih D.
name: Margolin, Frances S.
name: Alexander, Jeffrey A.
name: Combes, John R.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2008

description: To develop a taxonomy of governing board roles in U.S. hospitals.
Assessing Treatment Effects of Inhaled Corticosteroids on Medical Expenses and Exacerbations among COPD Patients: Longitudinal Analysis of Managed Care Claims
Creators: name: Akazawa, Manabu
name: Stearns, Sally C.
name: Biddle, Andrea K.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2008

description: To assess costs, effectiveness, and cost-effectiveness of inhaled corticosteroids (ICS) augmenting bronchodilator treatment for chronic obstructive pulmonary disease (COPD).
Transport Enhancement of Irregular Optical Lattices with Polychromatic Amplitude Modulation
Creators: name: Pepino, R. A.
name: Teh, W. P.
name: Magness, L. J.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Quantum Physics (quant-ph)
subject: Quantum Gases (cond-mat.quant-gas)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We demonstrate that the transport characteristics of deep optical lattices with one or multiple off-resonant external energy offsets can be greatly-enhanced by modulating the lattice depth in an exotic way. We derive effective stationary models for our proposed modulation schemes in the strongly interacting limit, where only one particle can occupy any given site. Afterwards we discuss the modifications necessary to recover transport when more than one particle may occupy the lattice sites. For the specific five-site lattices discussed, we numerically predict transport gains for ranging from $4.7\times 10^6$ to $9.8\times 10^{8}$.
description: 11 pages, 8 figures, 1 table, accepted for publication in the New Journal of Physics
Routed quantum circuits: an extended framework for coherent control and indefinite causal order
Creators: name: Vanrietvelde, Augustin
Publisher: name: Imperial College London
Year: 2022

description: Quantum circuits form the standard framework of quantum computing, and have started playing the same role for some parts of quantum foundations. However, they cannot satisfactorily capture some possibilities offered by quantum theory, in particular coherent control and indefinite causal order. In this thesis, we therefore propose an extension to this framework, given by routed quantum circuits. Our extension is based on the addition of sectorial constraints, which specify the basic sectorial structure of the scenarios at hand, on top of the factorial structure described by the connectivity of circuits. This yields a consistent and scalable framework, applicable to pure and mixed quantum theory. It admits a sound and intuitive diagrammatic notation. We show that this framework allows to properly model all forms of coherent control of the application of a channel, for instance the superposition of a quantum information carrier's trajectory, or the 'extended circuit diagrams' recently introduced for the study of causal decompositions. We demonstrate how this leads to a redefinition of the task of coherently controlling a channel, and study in detail the necessary resources for this task. We further show that the scenarios featuring indefinite causal order also fit within our framework once feedback loops are introduced. The connectivity and sectorial constraints are then sufficient to specify the core behaviour of a process, and in particular to check that it is valid, i.e. that its cycles do not lead to any logical inconsistency. We display how several standard examples of exotic processes, including ones that violate causal inequalities, are among the class of processes that can be generated in this way; we conjecture that this class in fact includes all unitarily extendible processes.
Impact of Physician Assistant Care on Office Visit Resource Use in the United States
Creators: name: Kaufman, Jay S.
name: Morgan, Perri A.
name: Shah, Nilay D.
name: Albanese, Mark A.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2008

description: To investigate whether the use of physician assistants (PAs) as providers for a substantive portion of a patient's office-based visits affects office visit resource use.
Intrinsic topological magnons in arrays of magnetic dipoles
Creators: name: Mellado, Paula
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We study a simple magnetic system composed of periodically modulated magnetic dipoles with an easy axis. Upon adjusting the modulation amplitude alone, chains and two-dimensional stacked chains exhibit a rich magnon spectrum where frequency gaps and magnon speeds are easily manipulable. The blend of anisotropy due to dipolar interactions between magnets and geometrical modulation induces a magnetic phase with fractional Zak number in infinite chains and end states in open one-dimensional systems. In two dimensions it gives rise to topological modes at the edges of stripes. Tuning the amplitude in two-dimensional lattices causes a band touching, which triggers the exchange of the Chern numbers of the volume bands and switches the sign of the thermal conductivity.
description: 9 figures
The Staffing-Outcomes Relationship in Nursing Homes: The Staffing-Outcomes Relationship
Creators: name: Konetzka, R. Tamara
name: Park, Jeongyoung
name: Stearns, Sally C.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2008

description: To assess longitudinally whether a change in registered nurse (RN) staffing and skill mix leads to a change in nursing home resident outcomes while controlling for the potential endogeneity of staffing.
Homogenisation of a Row of Dislocation Dipoles from Discrete Dislocation Dynamics
Creators: name: Chapman, Stephen Jonathan
name: Xiang, Yang
name: Zhu, Yichao
Publisher: name: arXiv
Year: 2015
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 74A60, 74N15, 41A60

description: Conventional discrete-to-continuum approaches have seen their limitation in describing the collective behaviour of the multi-polar configurations of dislocations, which are widely observed in crystalline materials. The reason is that dislocation dipoles, which play an important role in determining the mechanical properties of crystals, often get smeared out when traditional homogenisation methods are applied. To address such difficulties, the collective behaviour of a row of dislocation dipoles is studied by using matched asymptotic techniques. The discrete-to-continuum transition is facilitated by introducing two field variables respectively describing the dislocation pair density potential and the dislocation pair width. It is found that the dislocation pair width evolves much faster than the pair density. Such hierarchy in evolution time scales enables us to describe the dislocation dynamics at the coarse-grained level by an evolution equation for the slowly varying variable (the pair density) coupled with an equilibrium equation for the fast varying variable (the pair width). The time-scale separation method adopted here paves a way for properly incorporating dipole-like (zero net Burgers vector but non-vanishing) dislocation structures, known as the statistically stored dislocations (SSDs) into macroscopic models of crystal plasticity in three dimensions. Moreover, the natural transition between different equilibrium patterns found here may also shed light on understanding the emergence of the persistent slip bands (PSBs) in fatigue metals induced by cyclic loads.
Analytic approach to transport in superconducting junctions with arbitrary carrier density
Creators: name: Setiawan, F.
name: Hofmann, Johannes
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Gases (cond-mat.quant-gas)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Particle transport across Josephson junctions is commonly described using a simplifying approximation (often called the Andreev approximation), which assumes that excitations are fixed at the Fermi momentum and only Andreev reflections, with no normal reflections, occur at interfaces. While this approximation is appropriate for superconductors with high carrier density (for which the chemical potential vastly exceeds the pairing gap), it breaks down for low-carrier-density superconductors, such as topological superconductors, doped semiconductors, or superfluid quantum gases. Here, we present a general $analytical$ framework for transport in superconducting junctions that does not rely on this limiting Andreev approximation. We apply our framework to describe transport in junctions between $s$-wave superconductors along the BCS-BEC crossover, which interpolates between the conventional high-carrier-density (BCS-)regime and moderate- as well as low-carrier-density regimes (unitary and BEC regimes), for which the Andreev approximation is not valid. As the system is tuned from the BCS to the BEC regime, the magnitude of a subgap current due to multiple Andreev reflections (MAR) decreases. However, nonlinearities in the current-voltage characteristic become more pronounced near the intermediate unitary limit, giving rise to sharp peaks and dips in the differential conductance with even $negative$ differential conductance at specific voltages. Microscopically, the negative differential conductance is related to the van Hove points in the band structures, at which enhanced normal reflection occurs and that become accessible only when the chemical potential is comparable to or smaller than the pairing gap. The subgap current due to MAR vanishes at a critical interaction strength on the BEC side, which we identify as the splitting point where the particle dispersion changes curvature.
description: 26 pages, 12 figures, 1 table. Published version
Transportation Brokerage Services and Medicaid Beneficiaries' Access to Care
Creators: name: Stearns, Sally C.
name: Norton, Edward C.
name: Kim, Jinkyung
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2009

description: To examine the effect of capitated transportation brokerage services on Medicaid beneficiaries’ access to care and expenditures.
Sigma-model solitons on noncommutative spaces
Creators: name: Dabrowski, Ludwik
name: Landi, Giovanni
name: Luef, Franz
Publisher: name: arXiv
Year: 2015
Subjects: subject: Mathematical Physics (math-ph)
subject: Operator Algebras (math.OA)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We use results from time-frequency analysis and Gabor analysis to construct new classes of sigma-model solitons over the Moyal plane and over noncommutative tori, taken as source spaces, with a target space made of two points. A natural action functional leads to self-duality equations for projections in the source algebra. Solutions, having non-trivial topological content, are constructed via suitable Morita duality bimodules.
description: v2: minor changes
QEnclave -- A practical solution for secure quantum cloud computing
Creators: name: Ma, Yao
name: Kashefi, Elham
name: Arapinis, Myrto
name: Chakraborty, Kaushik
name: Kaplan, Marc
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Cryptography and Security (cs.CR)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: We introduce a secure hardware device named a QEnclave that can secure the remote execution of quantum operations while only using classical controls. This device extends to quantum computing the classical concept of a secure enclave which isolates a computation from its environment to provide privacy and tamper-resistance. Remarkably, our QEnclave only performs single-qubit rotations, but can nevertheless be used to secure an arbitrary quantum computation even if the qubit source is controlled by an adversary. More precisely, attaching a QEnclave to a quantum computer, a remote client controlling the QEnclave can securely delegate its computation to the server solely using classical communication. We investigate the security of our QEnclave by modeling it as an ideal functionality named Remote State Rotation. We show that this resource, similar to previously introduced functionality of remote state preparation, allows blind delegated quantum computing with perfect security. Our proof relies on standard tools from delegated quantum computing. Working in the Abstract Cryptography framework, we show a construction of remote state preparation from remote state rotation preserving the security. An immediate consequence is the weakening of the requirements for blind delegated computation. While previous delegated protocols were relying on a client that can either generate or measure quantum states, we show that this same functionality can be achieved with a client that only transforms quantum states without generating or measuring them.
description: 25 pages, 5 figures
Influence of spatial dispersion in metals on the optical response of deeply subwavelength slit arrays
Creators: name: Dechaux, Mathieu
name: Tichit, Paul-Henri
name: Ciracì, Cristian
name: Benedicto, Jessica
name: Pollès, Rémi
name: Centeno, Emmanuel
name: Smith, David R.
name: Moreau, Antoine
Publisher: name: arXiv
Year: 2015
Subjects: subject: Optics (physics.optics)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: In the framework of the hydrodynamic model describing the response of electrons in a metal, we show that arrays of very narrow and shallow metallic slits have an optical response that is influenced by the spatial dispersion in metals arising from the repulsive interaction between electrons. As a simple Fabry-Perot model is not accurate enough to describe the structure's behavior, we propose to consider the slits as generalized cavities with two modes, one being propagative and the other evanescent. This very general model allows to conclude that the impact of spatial dispersion on the propagative mode is the key factor explaining why the whole structure is sensitive to spatial dispersion. As the fabrication of such structures with relatively large gaps compared to previous experiments is within our reach, this work paves the way for future much needed experiments on nonlocality.
Phase diagram of the 2+1-dimensional Gross-Neveu model with chiral imbalance
Creators: name: Winstel, Marc
name: Pannullo, Laurin
name: Wagner, Marc
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In this work, the phase diagram of the $2+1$-dimensional Gross-Neveu model is investigated with baryon chemical potential as well as chiral chemical potential in the mean-field approximation. We study the theory using two lattice discretizations, which are both based on naive fermions. An inhomogeneous chiral phase is observed only for one of the two discretizations. Our results suggest that this phase disappears in the continuum limit.
description: 9 pages, 2 figures, contains ancillary files with plot data; talk given at the 38th International Symposium on Lattice Field theory (LATTICE 2021); July 26-30 2021
Short Assessment of Health Literacy-Spanish and English: A Comparable Test of Health Literacy for Spanish and English Speakers: Short Assessment of Health Literacy
Creators: name: Lee, Jessica Y.
name: Stucky, Brian D.
name: Lee, Shoou-Yih Daniel
name: Bender, Deborah E.
name: Rozier, R. Gary
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2010

description: The intent of the study was to develop and validate a comparable health literacy test for Spanish-speaking and English-speaking populations.
The Effect of the WIC Program on the Health of Newborns: Effect of WIC on the Health of Newborns
Creators: name: Gibson-Davis, Christina M.
name: Foster, E. Michael
name: Jiang, Miao
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2010

description: To determine the effect of the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) on birth outcomes.
Generative Quantum Learning of Joint Probability Distribution Functions
Creators: name: Zhu, Elton Yechao
name: Johri, Sonika
name: Bacon, Dave
name: Esencan, Mert
name: Kim, Jungsang
name: Muir, Mark
name: Murgai, Nikhil
name: Nguyen, Jason
name: Pisenti, Neal
name: Schouela, Adam
name: Sosnova, Ksenia
name: Wright, Ken
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Modeling joint probability distributions is an important task in a wide variety of fields. One popular technique for this employs a family of multivariate distributions with uniform marginals called copulas. While the theory of modeling joint distributions via copulas is well understood, it gets practically challenging to accurately model real data with many variables. In this work, we design quantum machine learning algorithms to model copulas. We show that any copula can be naturally mapped to a multipartite maximally entangled state. A variational ansatz we christen as a `qopula' creates arbitrary correlations between variables while maintaining the copula structure starting from a set of Bell pairs for two variables, or GHZ states for multiple variables. As an application, we train a Quantum Generative Adversarial Network (QGAN) and a Quantum Circuit Born Machine (QCBM) using this variational ansatz to generate samples from joint distributions of two variables for historical data from the stock market. We demonstrate our generative learning algorithms on trapped ion quantum computers from IonQ for up to 8 qubits and show that our results outperform those obtained through equivalent classical generative learning. Further, we present theoretical arguments for exponential advantage in our model's expressivity over classical models based on communication and computational complexity arguments.
description: 19 pages, 11 figures. v2: published version
Z-linear Gale duality and poly weighted spaces (PWS)
Creators: name: Rossi, Michele
name: Terracini, Lea
Publisher: name: arXiv
Year: 2015
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics

description: The present paper is devoted to discussing Gale duality from the Z-linear algebraic point of view. This allows us to isolate the class of Q-factorial complete toric varieties whose class group is torsion free, here called poly weighted spaces (PWS), as an interesting generalization of weighted projective spaces (WPS).
description: 29 pages: revised version to appear in Linear Algebra and Its Applications. Major changes: the paper has been largely rewritten following refree's comments. In particular, main geometric results have been anticipated giving rise to the motivational Section 2
Robust Hypothesis Testing with $α$-Divergence
Creators: name: Gül, Gökhan
name: Zoubir, Abdelhak M.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Other Statistics (stat.OT)
subject: FOS: Computer and information sciences

description: A robust minimax test for two composite hypotheses, which are determined by the neighborhoods of two nominal distributions with respect to a set of distances - called $α-$divergence distances, is proposed. Sion's minimax theorem is adopted to characterize the saddle value condition. Least favorable distributions, the robust decision rule and the robust likelihood ratio test are derived. If the nominal probability distributions satisfy a symmetry condition, the design procedure is shown to be simplified considerably. The parameters controlling the degree of robustness are bounded from above and the bounds are shown to be resulting from a solution of a set of equations. The simulations performed evaluate and exemplify the theoretical derivations.
description: Submitted to IEEE Trans. on Signal Processing
Insights in variability of global subduction zones from 2D and 3D numerical models and plate motion data
Creators: name: Suchoy, Lior
Publisher: name: Imperial College London
Year: 2022

description: Subduction of cold oceanic plates is a key driver of plate tectonics on Earth and has a wide range of surface expressions. The mechanisms governing subduction diversity are still debated. In this thesis, I investigate several key mechanisms using observations and numerical models of single plate subduction. First, I compile global subduction parameters along trenches from the last 120 Myr using recent global plate reconstruction models. The compilation highlights that trench motions generally contribute less than 20% to plate convergence, which has been attributed to low drag force at the base of the subducting plate. I investigate the role of basal drag using 2-D models of long and short plates including composite rheology. I show that even if basal drag force is low, it is expected to modify plate velocity significantly and that, in the Cenozoic record, its effect on velocity is masked because large-area plates experiencing significant basal drag have also been the ones with the highest driving slab pull. In particular for major subduction zones, some observed variability correlates with age-dependent variations of buoyancy and strength of the downgoing plate. Using a set of mechanical 3-D models, I show that to study Earth-like 'sinking' modes of subduction, the representation of plate buoyancy and strength needs to be carefully chosen. Next, I use these 3-D models to investigate the effect of lateral variations in plate buoyancy. Depending on the position of a buoyant ridge and whether the underlying plate is relatively old or young, the subduction of such a ridge modifies trench geometry and can either reduce or increase the shallow dip angle of the slab. These factors can explain why the impact of buoyant features is often different in West and East Pacific subduction zones. Thus variable plate strength and buoyancy and mantle drag significantly contribute to subduction diversity.
Increasing Time Costs and Copayments for Prescription Drugs: An Analysis of Policy Changes in a Complex Environment: Increasing Time Costs and Copayments for Prescription Drugs
Creators: name: Carey, Timothy S.
name: Richards, Shirley
name: Henson, Abel
name: Sleath, Betsy
name: Domino, Marisa Elena
name: Wiley-Exley, Elizabeth
name: Martin, Bradley C.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2011

description: To estimate the effect of two separate policy changes in the North Carolina Medicaid program: (1) reduced prescription lengths from 100 to 34 days' supply, and (2) increased copayments for brand name medications.
title: Humans of AI3SD: Paul Dingwall
Creators: name: Dingwall, Paul
name: Pauli, Michelle
Publisher: name: University of Southampton
Year: 2022
Subjects: AI3SD, Interview

description: This forms part of our Humans of AI3SD Series.

In this Humans of AI4SD interview he discusses data-driven approaches to mechanistic investigation, communicating across disciplines, the lack of progress with AI in synthetic chemistry, and his advice to early career researchers.
Cavity-enhanced field-free molecular alignment at a high repetition rate
Creators: name: Benko, Craig
name: Hua, Linqiang
name: Allison, Thomas K.
name: Labaye, François
name: Ye, Jun
Publisher: name: arXiv
Year: 2015
Subjects: subject: Optics (physics.optics)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Extreme ultraviolet frequency combs are a versatile tool with applications including precision measurement, strong-field physics, and solid-state physics. Here we report on an application of extreme ultraviolet frequency combs and their driving lasers for studying strong-field effects in molecular systems. We perform field-free molecular alignment and high-order harmonic generation with aligned molecules in a gas jet at a repetition rate of 154 MHz using a high-powered optical frequency comb inside a femtosecond enhancement cavity. The cavity-enhanced system provides a means to reach suitable intensities to study field-free molecular alignment and enhance the observable effects of the molecule-field interaction. We observe modulations of the driving field, arising from the nature of impulsive stimulated Raman scattering responsible for coherent molecular rotations. We foresee the impact of this work on the study of molecule-based strong-field physics, with improved precision and a more fundamental understanding of the interaction effects on both the field and molecules.
description: 5 pages, 5 figures
Neutrino Flavor Pendulum Reloaded: The Case of Fast Pairwise Conversion
Creators: name: Padilla-Gay, Ian
name: Tamborra, Irene
name: Raffelt, Georg G.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In core-collapse supernovae or compact binary merger remnants, neutrino-neutrino refraction can spawn fast pair conversion of the type $ν_e \barν_e \leftrightarrow ν_x \barν_x$ (with $x=μ, τ$), governed by the angle-dependent density matrices of flavor lepton number. In a homogeneous and axially symmetric two-flavor system, all angle modes evolve coherently, and we show that the nonlinear equations of motion are formally equivalent to those of a gyroscopic pendulum. Within this analogy, our main innovation is to identify the elusive characteristic of the lepton-number angle distribution that determines the depth of conversion with the "pendulum spin." The latter is given by the real part of the eigenfrequency resulting from the linear normal-mode analysis of the neutrino system. This simple analogy allows one to predict the depth of flavor conversion without solving the nonlinear evolution equations. Our approach provides a novel diagnostic tool to explore the physics of nonlinear systems.
description: Typo in Eq.(S20) of Appendix B corrected
HMOG: New Behavioral Biometric Features for Continuous Authentication of Smartphone Users
Creators: name: Sitova, Zdenka
name: Sedenka, Jaroslav
name: Yang, Qing
name: Peng, Ge
name: Zhou, Gang
name: Gasti, Paolo
name: Balagani, Kiran
Publisher: name: arXiv
Year: 2015
Subjects: subject: Cryptography and Security (cs.CR)
subject: FOS: Computer and information sciences

description: We introduce Hand Movement, Orientation, and Grasp (HMOG), a set of behavioral features to continuously authenticate smartphone users. HMOG features unobtrusively capture subtle micro-movement and orientation dynamics resulting from how a user grasps, holds, and taps on the smartphone. We evaluated authentication and biometric key generation (BKG) performance of HMOG features on data collected from 100 subjects typing on a virtual keyboard. Data was collected under two conditions: sitting and walking. We achieved authentication EERs as low as 7.16% (walking) and 10.05% (sitting) when we combined HMOG, tap, and keystroke features. We performed experiments to investigate why HMOG features perform well during walking. Our results suggest that this is due to the ability of HMOG features to capture distinctive body movements caused by walking, in addition to the hand-movement dynamics from taps. With BKG, we achieved EERs of 15.1% using HMOG combined with taps. In comparison, BKG using tap, key hold, and swipe features had EERs between 25.7% and 34.2%. We also analyzed the energy consumption of HMOG feature extraction and computation. Our analysis shows that HMOG features extracted at 16Hz sensor sampling rate incurred a minor overhead of 7.9% without sacrificing authentication accuracy. Two points distinguish our work from current literature: 1) we present the results of a comprehensive evaluation of three types of features (HMOG, keystroke, and tap) and their combinations under the same experimental conditions, and 2) we analyze the features from three perspectives (authentication, BKG, and energy consumption on smartphones).
$e^+e^-$ annihilation on the stochastic background of primordial gravitational waves with BKP18
Creators: name: Malsawmtluangi, N.
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The evolution of inflationary primordial gravitational waves with the expansion of the universe is studied while taking into account the $e^+e^-$ annihilation which leads to step correction in the spectrum of primordial gravitational waves which is $\sim 10\%$ in the amplitude and $\sim 25\%$ in the energy density. The amplitudes and energy densities are studied for the $α$-attractor inflation models which are in agreement with the recent BICEP/Keck and Planck 2018 joint result. The energy densities are well within the big bang nucleosynthesis bound, but the spectra for these models are very much below the detection range of the currently operating and upcoming detectors.
description: 13 pages, 6 figures
Is Direct Access to Obstetricians/Gynecologists Effective at Improving Maternal Health Behaviors?: Direct Access to OB/GYNs
Creators: name: Durrance, Christine Piette
name: Hankins, Scott
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2011

description: To examine the effects of state legislation mandating direct access to obstetricians and gynecologists (OB/GYNs) on maternal health behaviors and infant health outcomes.
On the stability of soliton and hairy black hole solutions of ${\mathfrak {su}}(N)$ Einstein-Yang-Mills theory with a negative cosmological constant
Creators: name: Baxter, J. Erik
name: Winstanley, Elizabeth
Publisher: name: arXiv
Year: 2015
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We investigate the stability of spherically symmetric, purely magnetic, soliton and black hole solutions of four-dimensional ${\mathfrak {su}}(N)$ Einstein-Yang-Mills theory with a negative cosmological constant $Λ$. These solutions are described by $N-1$ magnetic gauge field functions $ω_{j}$. We consider linear, spherically symmetric, perturbations of these solutions. The perturbations decouple into two sectors, known as the sphaleronic and gravitational sectors. For any $N$, there are no instabilities in the sphaleronic sector if all the magnetic gauge field functions $ω_{j}$ have no zeros, and satisfy a set of $N-1$ inequalities. In the gravitational sector, we are able to prove that there are solutions which have no instabilities in a neighbourhood of stable embedded ${\mathfrak {su}}(2)$ solutions, provided the magnitude of the cosmological constant $\left| Λ\right| $ is sufficiently large.
description: 43 pages, 4 figures, minor changes, discussion expanded and references updated. Matches version accepted for publication in J. Math. Phys
Translating Medical Evidence to Promote Informed Health Care Decisions: Decision Making about PSA
Creators: name: Treiman, Katherine
name: Poehlman, Jon
name: Cykert, Samuel
name: Golin, Carol
name: Williams-Piehota, Pamela
name: Lohr, Kathleen
name: McCormack, Lauren
name: Sheridan, Stacey
name: Soloe, Cindy
name: Bann, Carla
name: Driscoll, David
name: Harris, Russell
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2011

description: To examine the effects of a community-based intervention on decisions about prostate-specific antigen (PSA) screening using multiple measures of informed decision making (IDM).
title: Umanesimo metafisico e corpi ipofisici
Creators: name: Duque , Félix
Publisher: name: Roma Tre-Press
Year: 2013

description: Il presente saggio tratta della modernità e della centralità che l'uomo ha assunto nell'enorme cambiamento da essa segnato. Il saggio indaga tutte le forme di resistenza che vengono messe in gioco quando proviamo ad abbandonare le ultime manifestazioni di umanismo.

description: B@belonline vol. 14/15 Filosofia e pratiche filosofiche
Hypersymplectic structures with torsion on Lie algebroids
Creators: name: Antunes, P.
name: da Costa, J. M. Nunes
Publisher: name: arXiv
Year: 2015
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics

description: Hypersymplectic structures with torsion on Lie algebroids are investigated. We show that each hypersymplectic structure with torsion on a Lie algebroid determines three Nijenhuis morphisms. From a contravariant point of view, these structures are twisted Poisson structures. We prove the existence of a one-to-one correspondence between hypersymplectic structures with torsion and hyperkähler structures with torsion. We show that given a Lie algebroid with a hypersymplectic structure with torsion, the deformation of the Lie algebroid structure by any of the transition morphisms does not affect the hypersymplectic structure with torsion. We also show that if a triplet of $2$-forms is a hypersymplectic structure with torsion on a Lie algebroid $A$, then the triplet of the inverse bivectors is a hypersymplectic structure with torsion for a certain Lie algebroid structure on the dual $A^*$, and conversely. Examples of hypersymplectic structures with torsion are included.
description: arXiv admin note: text overlap with arXiv:1412.4992
Additional analysis on students' group project preferences
Creators: name: Benning, Tim
Publisher: name: Erasmus University Rotterdam (EUR)
Year: 2022
Subjects: Other education not elsewhere classified

description: This file contains a table including the additional analysis related to the article entitled "Reducing free-riding in group projects in line with students' preferences: Does it matter if there is more at stake?"
 A summary of the publication can be found below: Reducing free-riding is an important challenge for educators who use group projects. In this study, we measure students’ preferences for group project characteristics and investigate if characteristics that better help to reduce free-riding become more important for students when stakes increase. We used a discrete choice experiment based on twelve choice tasks in which students chose between two group projects that differed on five characteristics of which each level had its own effect on free-riding. A different group project grade weight was presented before each choice task to manipulate how much there was at stake for students in the group project. Data of 257 student respondents were used in the analysis. Based on random parameter logit model estimates we find that students prefer (in order of importance) assignment based on schedule availability and motivation or self-selection (instead of random assignment), the use of one or two peer process evaluations (instead of zero), a small team size of three or two students (instead of four), a common grade (instead of a divided grade), and a discussion with the course coordinator without a sanction as a method to handle free-riding (instead of member expulsion). Furthermore, we find that the characteristic team formation approach becomes even more important (especially self-selection) when student stakes increase. Educators can use our findings to design group projects that better help to reduce free-riding by (1) avoiding random assignment as team formation approach, (2) using (one or two) peer process evaluations, and (3) creating small(er) teams.
Behavioral sensitivity to interaural time differences in the rabbit
Creators: name: Patel, Mihir R.
name: Coffey, Charles S.
name: Fitzpatrick, Douglas C.
name: Blanks, Deidra A.
name: Ebert, Charles S.
name: Marshall, Allen F.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2008

description: An important cue for sound localization and separation of signals from noise is the interaural time difference (ITD). Humans are able to localize sounds within 1–2° and can detect very small changes in the ITD (10–20 μs). In contrast, many animals localize sounds with less precision than humans. Rabbits, for example, have sound localization thresholds of ~22°. There is only limited information about behavioral ITD discrimination in animals with poor sound localization acuity that are typically used for the neural recordings. For this study, we measured behavioral discrimination of ITDs in the rabbit for a range of reference ITDs from 0 to ± 300 μs. The behavioral task was conditioned avoidance and the stimulus was band-limited noise (500–1500 Hz). Across animals, the average discrimination threshold was 50–60 μs for reference ITDs of 0 to ± 200 μs. There was no trend in the thresholds across this range of reference ITDs. For a reference ITD of ± 300 μs, which is near the limit of the physiological window defined by the head width in this species, the discrimination threshold increased to ~100 μs. The ITD discrimination in rabbits less acute than in cats, which have a similar head size. This result supports the suggestion that ITD discrimination, like sound localization (see Heffner, 1997, Acta Otolaryngol Suppl 532:46–53, 1997) is determined by factors other than head size.
The iron regulatory axis of pulmonary artery vascular cells; disruption and implications for PAH subtypes
Creators: name: Toe, Quezia
Publisher: name: Imperial College London
Year: 2022

description: Introduction: Pulmonary artery hypertension (PAH) is a devastating and rare disease characterised by restricted flow through the pulmonary arterial circulation resulting in increased pulmonary vascular resistance; which ultimately results in right heart failure and death. Vascular remodelling is hypothesised to be caused by chronic inflammation, disrupted metabolism and dysregulated growth factors leading to endothelial and smooth muscle cell proliferation. Iron deficiency is prevalent in PAH and has been associated with reduced exercise capacity and increase mortality that makes iron deficiency clinically relevant and a potential therapeutic target for PAH. Systematically iron is regulated by the hepcidin/ferroportin axis, hepcidin, described as the global iron regulator, binds to ferroportin, an iron exporter, causing internalisation, thus preventing iron export. Hepcidin has been described to be elevated in patients with idiopathic PAH, therefore the present of this axis has been investigated in human pulmonary endothelial cells (hPAECs) and the manipulation of this axis will lead to iron retention by these cells with consequences that could influence responses locally of other surrounding cells. Methodology: hPAECs were grown and treated with either hepcidin, IL-6 or haemoglobin. Gene expression was examined by real-time PCR and protein expression by western blot or flow cytometry. hPAECs mediators release was determined by ELISA and proliferation by BrdU and MTS assays. hPAECs and 2 human smooth muscle cells (hPASMC) mitochondrial function were examined by the Seahorse assay. Conclusions: this study present findings that demonstrated the presence of the hepcidin/ferroportin in hPAECs that allows for local iron homeostatic control and modulation of this axis in these cells presents a PAH like phenotype that could contribute to vascular remodelling. Furthermore, IL-6 and hepcidin caused aberrant-BMPR2 signalling, in which BMPR2 protein is downregulated, however downstream signalling of BMPR2 remains active. The results present here here also supports the hypothesis that subclinical haemolysis may have a role in PAH pathophysiology.
Ontogeny of serotonin and serotonin2A receptors in rat auditory cortex
Creators: name: Manis, Paul B.
name: Walker, Paul D.
name: O’Donohue, Heather
name: Abbas, Atheir I.
name: Lauder, Jean M.
name: Roth, Bryan L.
name: Basura, Gregory J.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2008

description: Maturation of the mammalian cerebral cortex is, in part, dependent upon multiple coordinated afferent neurotransmitter systems and receptor-mediated cellular linkages during early postnatal development. Given that serotonin (5-HT) is one such system, the present study was designed to specifically evaluate 5-HT tissue content as well as 5-HT2A receptor protein levels within the developing auditory cortex (AC). Using high performance liquid chromatography (HPLC), 5-HT and the metabolite, 5-hydroxyindoleacetic acid (5-HIAA), was measured in isolated AC, which demonstrated a developmental dynamic, reaching young adult levels early during the second week of postnatal development. Radioligand binding of 5-HT2A receptors with the 5-HT2A/2C receptor agonist, 125I-DOI ((+/−)-1-(2,5- dimethoxy-4-iodophenyl)-2-aminopropane HCl; in the presence of SB206553, a selective 5-HT2C receptor antagonist, also demonstrated a developmental trend, whereby receptor protein levels reached young adult levels at the end of the first postnatal week (P8), significantly increased at P10 and at P17, and decreased back to levels not significantly different from P8 thereafter. Immunocytochemical labeling of 5-HT2A receptors and confocal microscopy revealed that 5-HT2A receptors are largely localized on layer II/III pyramidal cell bodies and apical dendrites within AC. When considered together, the results of the present study suggest that 5-HT, likely through 5-HT2A receptors, may play an important role in early postnatal AC development.
A posteriori estimates for the stochastic total variation flow
Creators: name: Baňas, Ľubomír
name: Wilke, André
Publisher: name: arXiv
Year: 2021
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics

description: We derive a posteriori error estimates for a fully discrete time-implicit finite element approximation of the stochastic total variaton flow (STVF) with additive space time noise. The estimates are first derived for an implementable fully discrete approximation of a regularized stochastic total variation flow. We then show that the derived a posteriori estimates remain valid for the unregularized flow up to a perturbation term that can be controlled by the regularization parameter. Based on the derived a posteriori estimates we propose a pathwise algorithm for the adaptive space-time refinement and perform numerical simulation for the regularized STVF to demonstrate the behavior of the proposed algorithm.