cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Competeing orders in spin-1 and spin-3/2 XXZ Kagome antiferromagnets: A series expansion study
Creators: name: Oitmaa, Jaan
name: Singh, Rajiv R. P.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We study the competition between $\sqrt{3} \times \sqrt{3}$ (RT3) and $q=0$ (Q0) magnetic orders in spin-one and spin-$3/2$ Kagome-lattice XXZ antiferromagnets with varying XY anisotropy parameter $Δ$, using series expansion methods. The Hamiltonian is split into two parts: an $H_0$ which favors the classical order in the desired pattern and an $H_1$, which is treated in perturbation theory by a series expansion. We find that the ground state energy series for the RT3 and Q0 phases are identical up to sixth order in the expansion, but ultimately a selection occurs, which depends on spin and the anisotropy $Δ$. Results for ground state energy and the magnetization are presented. These results are compared with recent spin-wave theory and coupled-cluster calculations. The series results for the phase diagram are close to the predictions of spin-wave theory. For the spin-one model at the Heisenberg point ($Δ=1$), our results are consistent with a vanishing order parameter, that is an absence of a magnetically ordered phase. We also develop series expansions for the ground state energy of the spin-one Heisenberg model in the trimerized phase. We find that the ground state energy in this phase is lower than those of magnetically ordered ones, supporting the existence of a spontaneously trimerized phase in this model.
description: 5 pages, 1 figure
The Transverse Momentum Dependent Fragmentation Function at NNLO
Creators: name: Echevarria, Miguel G.
name: Scimemi, Ignazio
name: Vladimirov, Alexey
Publisher: name: arXiv
Year: 2015
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We calculate the unpolarized transverse momentum dependent fragmentation function (TMDFF) at next-to-next-to-leading order (NNLO), evaluating separately TMD soft factor and TMD collinear correlator. For the first time the cancellation of spurious rapidity divergences in a properly defined individual TMD beyond the first non-trivial order is shown. This represents a strong check of the given TMD definition. We extract the matching coefficient necessary to perform the transverse momentum resummation at next-to-next-to-next-to-leading-logarithmic accuracy. The universal character of the soft function, which enters the definition of all (un)polarized TMD distribution/fragmentation functions, facilitates the future calculation of all the other TMDs and their coefficients at NNLO, pushing forward the accuracy of theoretical predictions for the current and next generation of high energy colliders.
description: v2: published version. v3: small corrections as published in erratum. List of changes at the end of preprint
Experiences of staff and service users delivering or receiving Making Every Contact Count and/or Healthy Conversation Skills as very brief or brief behaviour change interventions: a scoping review protocol
Creators: name: Parchment, Amelia
Publisher: name: Open Science Framework
Year: 2022
Subjects: subject: Social and Behavioral Sciences

description: The objective of this scoping review is to identify and map the available quantitative, qualitative and mixed methods evidence regarding the implementation of Making Every Contact Count and/or Healthy Conversation Skills for both staff delivering and service users receiving the intervention/s.
title: Data driven approaches to improving space weather forecasts for the power industry
Creators: name: Haines, Carl Andrew
Publisher: name: University of Reading
Year: 2022

description: Space weather impacts technological infrastructure in space and on Earth. This thesis focuses on impacts on power systems through geomagnetic ac�tivity. During heightened geomagnetic activity, currents can be induced in power lines and cause degradation of transformers. Therefore, it is useful to forecast the severity of geomagnetic storms and the resulting geomag�netically induced currents (GICs) so that mitigating action can be taken. This thesis faces this challenge through three bodies of work. The first two bodies focus on forecasting parameters of geomagnetic storms and the third provides a statistical downscaling scheme to aid forecasting of GICs. In the first body of work, the duration of geomagnetic storms is investigated. A statistical relationship is established between storm intensity and duration. A skilful and reliable forecast of storm duration (given storm peak intensity) is made, using log-normal distributions. In the second body of work, two pattern-matching approaches are taken to forecast the occurrence and intensity of geomagnetic storms in geomagnetic index data. The support vector machine and analogue ensemble are implemented for an historical dataset and evaluated using several metrics. It is found that both methods are skilful with respect to climatology and the best method is dependent on the needs of the end-user. The third body of work provides a downscaling scheme to improve the output of operational magnetospheric models such that a more realistic geoelectric field can be forecast. Using the analogue ensemble approach, a proof-of-concept study is presented which relates variability on a 1-hour timescale to a 1-minute timescale. Implemented using a perfect prognostic approach, the downscaling scheme enables a skilful estimate of geoelectric field with respect to the benchmark of no downscaling.
"We Are Not Afraid": An analysis of the Internet's effect in challenging the regime in Russia, 2011-2014
Creators: name: Tobin, Jessica
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2014

description: The Internet in Russia may have originally served as a safety valve, but the safety valve theory fails to account for what happens when people expressing their discontent in the cyber world brings about a resulting effect. This is what has taken place in Russia. The young, Internet-savvy generation has managed to harness the Internet to increase activism, instead of using it as an alternative to action. Their cyber actions have affected politics and society to some degree, as well as spurred street protests and provided an important independent voice in Russia’s constrained media sphere. This thesis will discuss some of these effects and the links between cyber actions and effect, thus questioning an unchallenged acceptance of the safety valve theory as it relates to the Russian case.
Low-Cost Superconducting Fan-Out with Cell I$_\text{C}$ Ranking
Creators: name: Volk, Jennifer
name: Tzimpragos, George
name: Wynn, Alex
name: Golden, Evan
name: Sherwood, Timothy
Publisher: name: arXiv
Year: 2022
Subjects: subject: Emerging Technologies (cs.ET)
subject: FOS: Computer and information sciences

description: Superconductor electronics (SCE) promise computer systems with orders of magnitude higher speeds and lower energy consumption than their complementary metal-oxide semiconductor (CMOS) counterparts. At the same time, the scalability and resource utilization of superconducting systems are major concerns. Some of these concerns come from device-level challenges and the gap between SCE and CMOS technology nodes, and others come from the way Josephson Junctions (JJs) are used. Towards this end, we notice that a considerable fraction of hardware resources are not involved in logic operations, but rather are used for fan-out and buffering purposes. In this paper, we ask if there is a way to reduce these overheads, propose the use of JJs at the cell boundaries to increase the number of outputs that a single stage can drive, and establish a set of rules to discretize critical currents in a way that is conducive to this assignment. Finally, we explore the design trade-offs that the presented approach opens up and demonstrate its promise through detailed analog simulations and modeling analyses. Our experiments indicate that the introduced method leads to a 48% savings in the JJ count for a tree with a fan-out of 1024, as well as an average of 43% of the JJ count for signal splitting and 32% for clock splitting in ISCAS'85 benchmarks.
description: 12 pages, 20 figures, accepted at IEEE TAS
Stochastic Optimally-Tuned Ranged-Separated Hybrid Density Functional Theory
Creators: name: Neuhauser, Daniel
name: Rabani, Eran
name: Cytter, Yael
name: Baer, Roi
Publisher: name: arXiv
Year: 2015
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: We develop a stochastic formulation of the optimally-tuned range-separated hybrid density functional theory which enables significant reduction of the computational effort and scaling of the non-local exchange operator at the price of introducing a controllable statistical error. Our method is based on stochastic representations of the Coulomb convolution integral and of the generalized Kohn-Sham density matrix. The computational cost of the approach is similar to that of usual Kohn-Sham density functional theory, yet it provides much more accurate description of the quasiparticle energies for the frontier orbitals. This is illustrated for a series of silicon nanocrystals up to sizes exceeding 3000 electrons. Comparison with the stochastic GW many-body perturbation technique indicates excellent agreement for the fundamental band gap energies, good agreement for the band-edge quasiparticle excitations, and very low statistical errors in the total energy for large systems. The present approach has a major advantage over one-shot GW by providing a self-consistent Hamiltonian which is central for additional post-processing, for example in the stochastic Bethe-Salpeter approach.
description: 7 pages, 3 figures
Lay understanding of time-bounded survival rates
Creators: name: Silver, Eric
Publisher: name: Open Science Framework
Year: 2022

description: We are interested in testing how the format of statistical information typically used for communicating the prognosis of a terminal disease affects an individual’s understanding of their own survival. The primary focus is on the communication of survival rates during a fixed time period (i.e, a 10% chance of surviving 5 years). One important characteristic of this communication is that doctors may select different durations to communicate survival of the same disease. As an example of how this might work, we include in our stimuli a 75% mortality rate over three years (henceforth the “3 year risk condition”) and a 90% mortality rate over five years (henceforth the “5 year risk condition”) as mortality characteristics that might credibly each describe the same disease and which each reflect a ~46% hazard rate. We implement a between-subjects combination of these two durations and survival rates to provide participants a hypothetical prognosis that communicates a survival rate and a duration.
Tidal Heating of Exomoons in Resonance and Implications for Detection
Creators: name: Tokadjian, Armen
name: Piro, Anthony L.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: The habitability of exoplanets can be strongly influenced by the presence of an exomoon, and in some cases the exomoon itself could be a possible place for life to develop. For moons outside of the habitable zone, significant tidal heating may raise their surface temperature enough to be considered habitable. Tidal heating of a moon depends on numerous factors such as eccentricity, semimajor axis, size of parent planet, and presence of additional moons. In this work, we explore the degree of tidal heating possible for multi-moon systems in resonance using a combination of semi-analytic and numerical models. This demonstrates that even for a moon with zero initial eccentricity, when it moves into resonance with an outer moon, it can generate significant eccentricity and associated tidal heating. Depending on the mass ratio of the two moons, this resonance can either be short-lived ($\leq200$ Myr) or continue to be driven by the tidal migration of the moons. This tidal heating can also assist in making the exomoons easier to discover, and we explore two scenarios: secondary eclipses and outgassing of volcanic species. We then consider hypothetical moons orbiting known planetary systems to identify which will be beast suited for finding exomoons with these methods. We conclude with a discussion of current and future instrumentation and missions to better understand how practical it will be to make exomoon discoveries in these ways.
description: 15 pages, 14 figures, updated with minor changes to match version accepted for publication in AJ
MEDINA Integrity Validation of Evidence - User Manual
Creators: name: Regueiro, Cristina
Publisher: name: Zenodo
Year: 2023
Subjects: Integrity Validation of Evidence
User Manual
Blockchain network
an audit trail of evidence
an audit trail of assessment results

description: The functionality of Integrity Validation of Evidence in MEDINA is provided by the Blockchain based MEDINA Evidence Trustworthiness Management System, which provides a secure mechanism to maintain an audit trail of evidence and assessment results. The MEDINA Evidence Trustworthiness Management System is implemented in Smart Contracts backboned by a common Blockchain network for all the MEDINA framework instances.
Effects of transdermal magnesium chloride on muscle damage and force production after eccentric exercise
Creators: name: Moore, Mason
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2017

description: PURPOSE: To determine if transdermal magnesium chloride (MgCl2) increases isometric force production and reduces muscle soreness after eccentric exercise. METHODS: In a double blind trial, participants were randomly assigned to a supplement before completing isometric force and muscle soreness testing. After 6 sets of 12 eccentric knee extensions, force and soreness were reassessed at 0, 24, 48, and 96 h. Supplements were applied three times per day. The other condition was repeated on the contralateral limb.  RESULTS: Peak torque significantly decreased by 20% after eccentric exercise. At 48 and 96h, condition A force was 9% and 5% higher but this was not significant. Muscle soreness was not different between conditions at any point. CONCLUSIONS: This preliminary analysis suggests that condition A may attenuate muscle force loss after eccentric exercise, leading to faster recovery. An accelerated recovery phase can potentially aid training intensity and duration as well as overall performance.
Dark photon vortex formation and dynamics
Creators: name: East, William E.
name: Huang, Junwu
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We study the formation and evolution of vortices in $U(1)$ dark photon dark matter and dark photon clouds that arise through black hole superradiance. We show how the production of both longitudinal mode and transverse mode dark photon dark matter can lead to the formation of vortices. After vortex formation, the energy stored in the dark photon dark matter will be transformed into a large number of vortex strings, eradicating the coherent dark photon dark matter field. In the case where a dark photon magnetic field is produced, bundles of vortex strings are formed in a superheated phase transition, and evolve towards a configuration consisting of many string loops that are uncorrelated on large scales, analogous to a melting phase transition in condensed matter. In the process, they dissipate via dark photon and gravitational wave emission, offering a target for experimental searches. Vortex strings were also recently shown to form in dark photon superradiance clouds around black holes, and we discuss the dynamics and observational consequences of this phenomenon with phenomenologically motivated parameters. In that case, the string loops ejected from the superradiance cloud, apart from producing gravitational waves, are also quantised magnetic flux lines and can be looked for with magnetometers. We discuss the connection between the dynamics in these scenarios and similar vortex dynamics found in type II superconductors.
description: 40 pages, 19 figures, updated to the journal version, with emphasis on the depletion of dark photon dark matter after vortex formation
A Worked Example of the Bayesian Mechanics of Classical Objects
Creators: name: Sakthivadivel, Dalton A R
Publisher: name: arXiv
Year: 2022
Subjects: subject: Classical Physics (physics.class-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Mathematical Physics (math-ph)
subject: Dynamical Systems (math.DS)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: Bayesian mechanics is a new approach to studying the mathematics and physics of interacting stochastic processes. Here, we provide a worked example of a physical mechanics for classical objects, which derives from a simple application thereof. We summarise the current state of the art of Bayesian mechanics in doing so. We also give a sketch of its connections to classical chaos, owing to a particular $\mathcal{N}=2$ supersymmetry.
description: 34 pages. Presentation revised and expository material added (v2). Condensed version to appear in The 3rd International Workshop on Active Inference
Quantum statistics of bosonic cascades
Creators: name: Liew, T. C. H.
name: Rubo, Y. G.
name: Sheremet, A. S.
name: De Liberato, S.
name: SHelykh, I. A.
name: Laussy, F. P.
name: Kavokin, A. V.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: Bosonic cascades formed by lattices of equidistant energy levels sustaining radiative transitions between nearest layers are promising for the generation of coherent terahertz radiation. We show how, also for the light emitted by the condensates in the visible range, they introduce new regimes of emission. Namely, the quantum statistics of bosonic cascades exhibit super-bunching plateaus. This demonstrates further potentialities of bosonic cascade lasers for the engineering of quantum properties of light useful for imaging applications.
MEDINA Credentials and Proofs of Certificates - User Manual
Creators: name: Regueiro, Cristina
Publisher: name: Zenodo
Year: 2023
Subjects: Self-Sovereign Identity
Verifiable credentials
User Manual

description: The functionality of checking Credentials and Proofs of Certificates in MEDINA is provided by the Self-Sovereign Identity (SSI) Framework tool. The SSI Framework provides Cloud Service Providers (CSPs) with the capability to manage their own security certificates as part of their identity through verifiable credentials. “To manage their own identity” ultimately means that they store their identity on their own “user space” without intervention of a third-party.
Unsupervised Voice Activity Detection by Modeling Source and System Information using Zero Frequency Filtering
Creators: name: Sarkar, Eklavya
name: Prasad, RaviShankar
name: -Doss, Mathew Magimai.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Audio and Speech Processing (eess.AS)
subject: Signal Processing (eess.SP)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Voice activity detection (VAD) is an important pre-processing step for speech technology applications. The task consists of deriving segment boundaries of audio signals which contain voicing information. In recent years, it has been shown that voice source and vocal tract system information can be extracted using zero-frequency filtering (ZFF) without making any explicit model assumptions about the speech signal. This paper investigates the potential of zero-frequency filtering for jointly modeling voice source and vocal tract system information, and proposes two approaches for VAD. The first approach demarcates voiced regions using a composite signal composed of different zero-frequency filtered signals. The second approach feeds the composite signal as input to the rVAD algorithm. These approaches are compared with other supervised and unsupervised VAD methods in the literature, and are evaluated on the Aurora-2 database, across a range of SNRs (20 to -5 dB). Our studies show that the proposed ZFF-based methods perform comparable to state-of-art VAD methods and are more invariant to added degradation and different channel characteristics.
description: Accepted at Interspeech 2022
Dynamical Mass Measurements of Contaminated Galaxy Clusters Using Machine Learning
Creators: name: Ntampaka, M.
name: Trac, H.
name: Sutherland, D. J.
name: Fromenteau, S.
name: Poczos, B.
name: Schneider, J.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We study dynamical mass measurements of galaxy clusters contaminated by interlopers and show that a modern machine learning (ML) algorithm can predict masses by better than a factor of two compared to a standard scaling relation approach. We create two mock catalogs from Multidark's publicly available $N$-body MDPL1 simulation, one with perfect galaxy cluster membership information and the other where a simple cylindrical cut around the cluster center allows interlopers to contaminate the clusters. In the standard approach, we use a power-law scaling relation to infer cluster mass from galaxy line-of-sight (LOS) velocity dispersion. Assuming perfect membership knowledge, this unrealistic case produces a wide fractional mass error distribution, with a width of $Δε\approx0.87$. Interlopers introduce additional scatter, significantly widening the error distribution further ($Δε\approx2.13$). We employ the support distribution machine (SDM) class of algorithms to learn from distributions of data to predict single values. Applied to distributions of galaxy observables such as LOS velocity and projected distance from the cluster center, SDM yields better than a factor-of-two improvement ($Δε\approx0.67$) for the contaminated case. Remarkably, SDM applied to contaminated clusters is better able to recover masses than even the scaling relation approach applied to uncontaminated clusters. We show that the SDM method more accurately reproduces the cluster mass function, making it a valuable tool for employing cluster observations to evaluate cosmological models.
description: 18 pages, 12 figures, accepted for publication at ApJ
Where to Begin? On the Impact of Pre-Training and Initialization in Federated Learning
Creators: name: Nguyen, John
name: Wang, Jianyu
name: Malik, Kshitiz
name: Sanjabi, Maziar
name: Rabbat, Michael
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: An oft-cited challenge of federated learning is the presence of heterogeneity. \emph{Data heterogeneity} refers to the fact that data from different clients may follow very different distributions. \emph{System heterogeneity} refers to client devices having different system capabilities. A considerable number of federated optimization methods address this challenge. In the literature, empirical evaluations usually start federated training from random initialization. However, in many practical applications of federated learning, the server has access to proxy data for the training task that can be used to pre-train a model before starting federated training. Using four standard federated learning benchmark datasets, we empirically study the impact of starting from a pre-trained model in federated learning. Unsurprisingly, starting from a pre-trained model reduces the training time required to reach a target error rate and enables the training of more accurate models (up to 40\%) than is possible when starting from random initialization. Surprisingly, we also find that starting federated learning from a pre-trained initialization reduces the effect of both data and system heterogeneity. We recommend future work proposing and evaluating federated optimization methods to evaluate the performance when starting from random and pre-trained initializations. This study raises several questions for further work on understanding the role of heterogeneity in federated optimization. \footnote{Our code is available at: \url{https://github.com/facebookresearch/where_to_begin}}
description: Accepted at ICLR
Exploring the experiential elements of quality participation for children and youth with intellectual and developmental disabilities: A protocol for a systematic scoping review
Creators: name: Bruno, Natasha
name: Richardson, Alanna
name: Kauffeldt, Kaitlyn
name: Tomasone, Jennifer
name: Arbour-Nicitopoulos, Kelly
name: Latimer-Cheung, Amy
Publisher: name: Open Science Framework
Year: 2022
Subjects: subject: Children
subject: Developmental Disability
subject: Intellectual Disability
subject: Quality Experiences
subject: Quality Participation
subject: Systematic Scoping Review
subject: Youth

description: A systematic scoping review examining experiential elements and strategies associated with quality participation among children and youth (2- 12 years) with intellectual and developmental disabilities (IDDs).
Associations Between Quadriceps Muscle Quality, Quadriceps Function, and Functional Ability
Creators: name: Dibbert, Ashley
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2019

description: Anterior cruciate ligament (ACL) injury and surgical reconstruction (ACLR) increase the risk of post-traumatic knee osteoarthritis (PTOA). Quadriceps dysfunction is a common, lingering complication following ACLR that may contribute to the heightened risk of knee PTOA. Factors contributing to quadriceps dysfunction may be arthrogenic muscle inhibition (AMI) and an increase in intramuscular adipose tissue (IMAT). Understanding the mechanisms of progression from ACLR to knee PTOA and underlying causes is critical for developing effective rehabilitation methods. Quadriceps muscle quality (QMQ) can be assessed via ultrasound echo intensity (EI), with higher values representing poorer QMQ. EI may estimate functional performance, as assessed by peak torque (PT). PT is an important indicator in making return to sport (RTS) decisions post-ACLR, and may influence PTOA risk. Aside from knee extension PT, functional outcomes such as single-leg hop are important in making RTS decisions. EI may be an appropriate measure of quadriceps function and functional outcomes post-ACLR, but the association between EI and functional test performance is unclear. Since EI is correlated with strength, it may prove of use for making RTS decisions. Quadriceps strength predicts hop test performances, which may indicate a possible relationship between functional outcomes and QMQ. The purposes of this study were to evaluate the associations between QMQ (EI), quadriceps function (knee extension PT), and functional outcomes (single-leg hop) in individuals with ACLR. We hypothesized that higher EI values (i.e. poorer QMQ) would be associated with lower quadriceps function (PT) and poorer functional outcomes (i.e. single-leg hop). EI, PT, and single-leg hop distance were assessed in 36 ACLR individuals. EI was assessed as the average grayscale value of the muscle cross-sectional area (CSA), excluding the muscle fascia and subcutaneous fat thickness. PT was assessed as the maximum torque generated by the quadriceps. Single-leg hop distance was assessed as the average of three hop trials for maximum distance on the ACLR limb. The primary findings of this study were that there was a moderate negative correlation between EI and PT and a strong negative correlation between EI and single- leg hop distance in the ACLR limb. These findings are consistent with the experimental hypotheses. Our findings suggest that muscle quality is indicative of quadriceps function and functional ability in individuals with ACLR, and may be a potential RTS criterion following ACLR and the rehabilitation process. Therefore, strategies to improve QMQ may result in an increase in functional performance, improve RTS outcomes, and decrease the risk of knee PTOA in ACLR individuals. Future research may evaluate QMQ in the clinical setting for RTS decisions and explore similar correlations in other populations.
MEDINA Orchestrator - User Manual
Creators: name: Kunz, Immanuel
Publisher: name: Zenodo
Year: 2023
Subjects: Evidence management
Assessment results
User Manual

description: The Orchestrator is a central component of the MEDINA framework and processes and stores all evidence and assessment results. It receives them from the evidence collection and security assessment tools, and forwards them to the appropriate components, such as the Continuous Certificated Evaluation[1] (CCE). Furthermore, it provides a database that stores evidence and assessment results, as well as metrics, and other data.
The Utility of College Awareness Programs for Middle School Students: An Evaluation of the First Look Program at UNC Chapel Hill
Creators: name: May, Morgan M.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2015

description: This research will evaluate the landscape of college awareness programs for middle
school students and will both audit the First Look program based on best practices and analyze
the existing evaluation data provided by the program. Scholarship surrounding current national
college access programming will guide the First Look audit by reviewing First Look’s mission
statement and programming documents. Additionally, archival participant questionnaires will be
analyzed. This evaluation seeks to assess the effectiveness of the UNC-CH First Look program
as an early college awareness program for middle school students. These findings can
specifically enhance the First Look program and the analyses can set direction for broader policy
and practice implications for future college access at the middle school level.
Stabilizing Quantum States and Automatic Error Correction by Dissipation Control
Creators: name: Pan, Yu
name: Nguyen, Thien
Publisher: name: arXiv
Year: 2015
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In this paper an extended scalability condition is proposed to achieve the ground-state stability for a class of multipartite quantum systems which may involve two-body interactions, and an explicit procedure to construct the dissipation control is presented. Moreover, we show that dissipation control can be used for automatic error correction in addition to stabilization. We demonstrate the stabilization and error correction of three-qubit repetition code states using dissipation control.
description: 7 pages, 3 figures
Anisotropic Behavior of the Thermoelectric Power and the Thermal Conductivity in a Unidirectional Lateral Superlattice: A Typical Anisotropic System Exhibiting Two Distinct Nernst Coefficients
Creators: name: Endo, Akira
name: Katsumoto, Shingo
name: Iye, Yasuhiro
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We have calculated the thermoelectric conductivity tensor $\varepsilon_{ij}$ and the thermal conductivity tensor $λ_{ij}$ of a unidirectional lateral superlattice (ULSL) ($i,j = x,y$, with the $x$-axis aligned to the principal axis of the ULSL), %, given as the first- and the second-order moments, employing based on the asymptotic analytic formulas of the electrical conductivity tensor $σ_{ij}$ in the literature valid at low magnetic fields where large numbers of Landau levels are occupied. With the resulting analytic expressions, we clarify the conditions for the Mott formula (Wiedemann-Franz law) to be applicable with high precision to $\varepsilon_{ij}$ ($λ_{ij}$). We further present plots of the commensurability oscillations $δ\varepsilon_{ij}$, $δλ_{ij}$, $δκ_{ij}$, and $δS_{ij}$ in $\varepsilon_{ij}$, $λ_{ij}$, (an alternative, more standard definition of) the thermal conductivity tensor $κ_{ij}$, and the thermopower tensor $S_{ij}$, calculated using typical parameters for a ULSL fabricated from a GaAs/AlGaAs two-dimensional electron gas (2DEG). Notable features of the $δS_{ij}$ are (i) anisotropic behavior ($δS_{xx} \ne δS_{yy}$) and (ii) the dominance of the $xy$ component over the other components ($|δS_{xy}| \gg |δS_{yx}|, |δS_{xx}|, |δS_{yy}|$). The latter clearly indicates that the two Nernst coefficients, $S_{xy}$ and $S_{yx}$, can be totally different from each other in an anisotropic system. Both (i) and (ii) are at variance with the previous theory and are attributable to the inclusion of a damping factor due to the small-angle scattering characteristic of GaAs/AlGaAs 2DEGs, which have not been taken into consideration in $δS_{ij}$ thus far.
description: 14 pages, 9 figures, Title and Introduction altered to make the main point of the paper clearer. Minor revisions throughout the paper. Some additions to the IV Discussion. Explicit energy dependence of the zero-temperature conductivity newly presented in the Appendix
Relaxation models for Single Helical Reversed Field Pinch plasmas
Creators: name: Paccagnella, Roberto
Publisher: name: arXiv
Year: 2015
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: In this paper a relaxation theory, proposed several years ago for plasmas where a single dominant mode is present, is revisited. The solutions of the related eigenvalue problem are numerically calculated and discussed. Although these solutions are very rich and can reproduce well the magnetic fields measured in experiments, there is no manner within the theory to determine the dominant helicity, which is a free parameter in the model. To find the preferred helicity in the system, we propose to minimize the distance of the relaxed state from another state which is constructed as a two region generalization of the Taylor relaxation model allowing current jumps. It is found that this comparison is able to predict the observed scaling with the aspect ratio and reversal parameter for the dominant mode in the Single Helical states.
Electronic friction-based vibrational lifetimes of molecular adsorbates: Beyond the independent atom approximation
Creators: name: Rittmeyer, Simon P.
name: Meyer, Jörg
name: Juaristi, J. Iñaki
name: Reuter, Karsten
Publisher: name: arXiv
Year: 2015
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We assess the accuracy of vibrational damping rates of diatomic adsorbates on metal surfaces as calculated within the local-density friction approximation (LDFA). An atoms-in-molecules (AIM) type charge partitioning scheme accounts for intra-molecular contributions and overcomes the systematic underestimation of the non-adiabatic losses obtained within the prevalent independent atom approximation. The quantitative agreement obtained with theoretical and experimental benchmark data suggests the LDFA-AIM as an efficient and reliable approach to account for electronic dissipation in ab initio molecular dynamics simulations of surface chemical reactions.
description: 5 pages including 2 figures
A Pre-Gaia Census of Nearby Stellar Groups
Creators: name: Mamajek, Eric E.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: The nearest, youngest groups of stars to the Sun provide important samples of age-dated stars for studying circumstellar disk evolution, imaged exoplanets, and brown dwarfs. I briefly comment on the status of the known stellar groups within 100 pc: $β$ Pic, AB Dor, UMa, Car-Near, Tuc-Hor and $β$ Tuc nucleus, Hyades, Col, TW Hya, Car, Coma Ber, 32 Ori, $η$ Cha, and $χ^1$ For. I also discuss some poorly characterized groups and "non-groups." Grades for 2015 of Pass, Satisfactory, or Fail are assigned to the groups for the purposes of age-dating stars and brown dwarfs. I speculate that Tuc-Hor could have provided a supernova ~60 pc away ~2.2 Myr ago which showered the Earth with traces of 60Fe-bearing dust.
description: 6 pages, Proceedings IAU Symposium No. 314, Young Stars & Planets Near the Sun, 2015, J. H. Kastner, B. Stelzer, & S. A. Metchev, eds
Active Learning Strategies used in Dental Education
Creators: name: Sette-de-Souza, Pedro
Publisher: name: Open Science Framework
Year: 2022
Subjects: subject: Dental Public Health and Education
subject: Medicine and Health Sciences
subject: Dentistry
subject: FOS: Clinical medicine

description: This study aimed to perform a critical appraisal of active learning strategies in dental education. The search terms to be used are “active methodologies”, “active teaching”, “dental education”, “dentistry” and their combinations. Works that are not original research, review studies, or case reports will be excluded from the research. Original research papers, which reported using at least one form of active/innovative methodology in dental education, will be included.
Learning Robust Representation for Joint Grading of Ophthalmic Diseases via Adaptive Curriculum and Feature Disentanglement
Creators: name: Che, Haoxuan
name: Jin, Haibo
name: Chen, Hao
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Diabetic retinopathy (DR) and diabetic macular edema (DME) are leading causes of permanent blindness worldwide. Designing an automatic grading system with good generalization ability for DR and DME is vital in clinical practice. However, prior works either grade DR or DME independently, without considering internal correlations between them, or grade them jointly by shared feature representation, yet ignoring potential generalization issues caused by difficult samples and data bias. Aiming to address these problems, we propose a framework for joint grading with the dynamic difficulty-aware weighted loss (DAW) and the dual-stream disentangled learning architecture (DETACH). Inspired by curriculum learning, DAW learns from simple samples to difficult samples dynamically via measuring difficulty adaptively. DETACH separates features of grading tasks to avoid potential emphasis on the bias. With the addition of DAW and DETACH, the model learns robust disentangled feature representations to explore internal correlations between DR and DME and achieve better grading performance. Experiments on three benchmarks show the effectiveness and robustness of our framework under both the intra-dataset and cross-dataset tests.
description: Accepted by MICCAI22
MEDINA Customization of Requirements - User Manual
Creators: name: Ciampoli, Patrizia
Publisher: name: Zenodo
Year: 2023
Subjects: Security Requirements
Obligations
User Manual

description: The Customization of Requirements functionality in MEDINA is provided by the CNL Editor tool. CNL Editor is a Web application, accessible via an Internet browser, which allows to view the Requirement and Obligations (REO) defined for Cloud Services and to make some changes to them.
Strong correlations generically protect d-wave superconductivity against disorder
Creators: name: Tang, Shao
name: Dobrosavljevic, V.
name: Miranda, E.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We address the question of why strongly correlated d-wave superconductors, such as the cuprates, prove to be surprisingly robust against the introduction of non-magnetic impurities. We show that, very generally, both the pair-breaking and the normal state transport scattering rates are significantly suppressed by strong correlations effects arising in the proximity to a Mott insulating state. We also show that the correlation-renormalized scattering amplitude is generically enhanced in the forward direction, an effect which was previously often ascribed to the specific scattering by charged impurities outside the copper-oxide planes.
description: 4+e pages
Asymptotic Spectral Flow
Creators: name: Dai, Xianzhe
name: Li, Yihan
Publisher: name: arXiv
Year: 2022
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics

description: In this paper we study the asymptotic behavior of the spectral flow of a one-parameter family $\{D_s\}$ of Dirac operators acting on the spinor bunldle $S$ twisted by a vector bundle $E$ of rank $k$, with the parameter $s\in [0,r]$ when $r$ gets sufficiently large. Our method uses the variation of eta invariant and local index theory technique. The key is a uniform estimate of the eta invariant $\barη(D_r)$ which is established via local index theory technique and heat kernel estimate.
Localized Single Frequency Lasing States in a Finite Parity-Time Symmetric Resonator Chain
Creators: name: Phang, Sendy
name: Vukovic, Ana
name: Creagh, Stephen C.
name: Sewell, Phillip D.
name: Gradoni, Gabriele
name: Benson, Trevor M.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: In this paper a practical case of a finite periodic Parity Time chain made of resonant dielectric cylinders is considered. The paper analyzes a more general case where PT symmetry is achieved by modulating both the real and imaginary part of the material refractive index along the resonator chain. The band-structure of the finite periodic PT resonator chains is compared to infinite chains in order to understand the complex interdependence of the Bloch phase and the amount of the gain/loss in the system that causes the PT symmetry to break. The results show that the type of the modulation along the unit cell can significantly affect the position of the threshold point of the PT system. In all cases the lowest threshold is achieved near the end of the Brillouin zone. In the case of finite PT-chains, and for a particular type of modulation, early PT symmetry breaking is observed and shown to be caused by the presence of termination states localized at the edges of the finite chain resulting in localized lasing and dissipative modes at each end of the chain.
description: 8 Figures and 12 pages
Attosecond magnetization dynamics in non-magnetic materials driven by intense femtosecond lasers
Creators: name: Neufeld, Ofer
name: Tancogne-Dejean, Nicolas
name: De Giovannini, Umberto
name: Hübener, Hannes
name: Rubio, Angel
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Irradiating solids with ultrashort laser pulses is known to initiate femtosecond timescale magnetization dynamics. However, sub-femtosecond spin dynamics have not yet been observed or predicted. Here, we explore ultrafast light-driven spin dynamics in a highly non-resonant strong-field regime. Through state-of-the-art ab-initio calculations, we predict that a non-magnetic material can be transiently transformed into a magnetic one via dynamical extremely nonlinear spin-flipping processes, which occur on attosecond timescales and are mediated by a combination of multi-photon and spin-orbit interactions. These are non-perturbative non-resonant analogues to the inverse Faraday effect that build up from cycle-to-cycle as electrons gain angular momentum. Remarkably, we show that even for linearly polarized driving, where one does not intuitively expect any magnetic response, the magnetization transiently oscillates as the system interacts with light. This oscillating response is enabled by transverse anomalous light-driven currents in the solid, and typically occurs on timescales of ~500 attoseconds. We further demonstrate that the speed of magnetization can be controlled by tuning the laser wavelength and intensity. An experimental set-up capable of measuring these dynamics through pump-probe transient absorption spectroscopy is outlined and simulated. Our results pave the way for new regimes of ultrafast manipulation of magnetism.
description: 21 pages, 14 figures
MEDINA Continuous Certificate Evaluation - User Manual
Creators: name: Ratkajec, Hrvoje
Publisher: name: Zenodo
Year: 2023
Subjects: Certificate evaluation
User Manual

description: The Continuous Certification Evaluation (CCE) component of MEDINA collects assessment results and builds an evaluation tree representing the aggregated assessment results on higher levels of the certification scheme to determine compliance with the different certification elements.
Analysis of Faunal Remains at the Wall Site in Hillsboro, NC
Creators: name: Wells, Ava Noelle
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2016

description: The goal of this thesis is to analyze a faunal assemblage in order to improve knowledge of precontact Native American subsistence practices at the Wall site. Through the analysis of data from this assemblage, we can gain a better understanding of not only their diet, but also possible hunting techniques for precontact in the area. This analysis provides new information on the Wall site, and Native American archaeology in North Carolina as a whole, and helps us to better understand the archaeology of the surrounding area.
Tachyon condensation in a chromomagnetic background field and the groundstate of QCD
Creators: name: Bordag, M.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: I consider the chromomagnetic vacuum in SU(2). The effective Lagrangian in one loop approximation is known to have a minimum below zero which results in a spontaneously generated magnetic field. However, this minimum is not stable; the effective action has an imaginary part. Over the past decades, there were many attempts to handle this situation which all were at some point unsatisfactory. I propose an idea for a new solution by assuming that the tachyonic mode, at low temperature, acquires a condensate and, as a result, undergoes a phase transition like in the Higgs model. I consider the approximation where all gluon modes are dropped except for the tachyonic one. For this mode, we have a O(2)-model with quartic self-interaction in two dimensions. I apply the CJT (2PI) formalism in the Hartree approximation. As a result, at zero and low temperatures, a minimum of the effective action at a certain value of the condensate and of the background fields is observed and there is no imaginary part. Raising the temperature, this minimum becomes shallower and at a critical temperature, the perturbative state becomes that with lower effective potential; the symmetry is restored. The physical interpretation says that the unstable mode creates tachyons until these come into equilibrium with their repulsive self-interaction and form a condensate. The relation to the Mermin-Wagner theorem is discussed. }
description: 8pages, 3 figures, several improvements
Strichartz estimates in similarity coordinates and stable blowup for the critical wave equation
Creators: name: Donninger, Roland
Publisher: name: arXiv
Year: 2015
Subjects: subject: Analysis of PDEs (math.AP)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: We establish Strichartz estimates in similarity coordinates for the radial wave equation in three spatial dimensions with a (time-dependent) self-similar potential. As an application we consider the critical wave equation and prove the asymptotic stability of the ODE blowup profile in the energy space.
description: 39 pages, referees' suggestions incorporated, typos fixed, more references added; will appear in Duke Math. J