cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Prediction, Learning, Uniform Convergence, and Scale-sensitive Dimensions
Creators: name: Bartlett, Peter L.
name: Long, Philip M.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Machine Learning (cs.LG)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: We present a new general-purpose algorithm for learning classes of $[0,1]$-valued functions in a generalization of the prediction model, and prove a general upper bound on the expected absolute error of this algorithm in terms of a scale-sensitive generalization of the Vapnik dimension proposed by Alon, Ben-David, Cesa-Bianchi and Haussler. We give lower bounds implying that our upper bounds cannot be improved by more than a constant factor in general. We apply this result, together with techniques due to Haussler and to Benedek and Itai, to obtain new upper bounds on packing numbers in terms of this scale-sensitive notion of dimension. Using a different technique, we obtain new bounds on packing numbers in terms of Kearns and Schapire's fat-shattering function. We show how to apply both packing bounds to obtain improved general bounds on the sample complexity of agnostic learning. For each $ε> 0$, we establish weaker sufficient and stronger necessary conditions for a class of $[0,1]$-valued functions to be agnostically learnable to within $ε$, and to be an $ε$-uniform Glivenko-Cantelli class. This is a manuscript that was accepted by JCSS, together with a correction.
description: One header page, a three page correction, then a 28 page original paper
Southwestern Blackduck: Political Boundaries Versus Archaeological Reality
Creators: name: Carr, Jackson S.
Publisher: name: Arts
Year: 2023
Subjects: subject: Northeastern Plains
subject: Blackduck
subject: Ceramic Analysis
subject: North Dakota
subject: Minnesota
subject: Late Woodland Period
subject: Archaeology

description: Late Woodland Blackduck ceramics are a highly recognizable and well-documented phenomenon in the archaeological record of Minnesota, Ontario, and Manitoba. The presently acknowledged southwestern boundary for Blackduck ceramics, is the Red River of the North in Minnesota and the southern border of Manitoba. This rather strict, classically held boundary fails to recognize western Blackduck cultural adaptation within the current understanding of this archaeological culture, in addition to promoting erroneous classifications of Woodland-affiliated ceramics in North Dakota. The research herein details the presence of Blackduck in the western margins of Minnesota and the prairies of North Dakota by examining 19 sites believed to contain Blackduck ceramics. This thesis expands knowledge of the Late Woodland Period throughout the Northeastern Plains by delineating the southwestern boundary for Blackduck through basic ceramics analysis. A summarization and reconstruction of the Late Woodland Period in North Dakota is supported by the presentation of a new ceramic ware for the state. Previous models for the movement and interaction of Blackduck makers will also be examined and re-contextualized within theoretical paradigms that seek to unify people and their environment into one entity.
Bayesian inference of galaxy formation from the K-band luminosity function of galaxies: tensions between theory and observation
Creators: name: Lu, Yu
name: Mo, H. J.
name: Katz, Neal
name: Weinberg, Martin D.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We conduct Bayesian model inferences from the observed K-band luminosity function of galaxies in the local Universe, using the semi-analytic model (SAM) of galaxy formation introduced in Lu et al (2011). The prior distributions for the 14 free parameters include a large range of possible models. We find that some of the free parameters, e.g. the characteristic scales for quenching star formation in both high-mass and low-mass halos, are already tightly constrained by the single data set. The posterior distribution includes the model parameters adopted in other SAMs. By marginalising over the posterior distribution, we make predictions that include the full inferential uncertainties for the colour-magnitude relation, the Tully-Fisher relation, the conditional stellar mass function of galaxies in halos of different masses, the HI mass function, the redshift evolution of the stellar mass function of galaxies, and the global star formation history. Using posterior predictive checking with the available observational results, we find that the model family (i) predicts a Tully-Fisher relation that is curved; (ii) significantly over predicts the satellite fraction; (iii) vastly over predicts the HI mass function; (iv) predicts high-z stellar mass functions that have too many low mass galaxies and too few high mass ones. and (v) predicts a redshift evolution of the stellar mass density and the star formation history that are in moderate disagreement. These results suggest that some important processes are still missing in the current model family and we discuss a number of possible solutions to solve the discrepancies, such as interactions between galaxies and dark matter halos, tidal stripping, the bimodal accretion of gas, preheating, and a redshift-dependent initial mass function.
description: 45 pages, 12 figures, MNRAS in press
Exploring single-sample SNP and INDEL calling with whole-genome de novo assembly
Creators: name: Li, Heng
Publisher: name: arXiv
Year: 2012
Subjects: subject: Genomics (q-bio.GN)
subject: FOS: Biological sciences

description: Motivation: Eugene Myers in his string graph paper (Myers, 2005) suggested that in a string graph or equivalently a unitig graph, any path spells a valid assembly. As a string/unitig graph also encodes every valid assembly of reads, such a graph, provided that it can be constructed correctly, is in fact a lossless representation of reads. In principle, every analysis based on whole-genome shotgun sequencing (WGS) data, such as SNP and insertion/deletion (INDEL) calling, can also be achieved with unitigs. Results: To explore the feasibility of using de novo assembly in the context of resequencing, we developed a de novo assembler, fermi, that assembles Illumina short reads into unitigs while preserving most of information of the input reads. SNPs and INDELs can be called by mapping the unitigs against a reference genome. By applying the method on 35-fold human resequencing data, we showed that in comparison to the standard pipeline, our approach yields similar accuracy for SNP calling and better results for INDEL calling. It has higher sensitivity than other de novo assembly based methods for variant calling. Our work suggests that variant calling with de novo assembly be a beneficial complement to the standard variant calling pipeline for whole-genome resequencing. In the methodological aspects, we proposed FMD-index for forward-backward extension of DNA sequences, a fast algorithm for finding all super-maximal exact matches and one-pass construction of unitigs from an FMD-index. Availability: http://github.com/lh3/fermi Contact: hengli@broadinstitute.org
description: Rev2: submitted version with minor improvements; 7 pages
The origin of the difference between space and time
Creators: name: Nikolic, Hrvoje
Publisher: name: arXiv
Year: 1999
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: All differences between the role of space and time in nature are explained by proposing the principles in which none of the spacetime coordinates has an {\it a priori} special role. Spacetime is treated as a non-dynamical manifold, with a fixed global $\mathbb{R}^D$ topology. Dynamical theory of gravity determines only the metric tensor on a fixed manifold. All dynamics is treated as a Cauchy problem, so it {\em follows} that one coordinate takes a special role. It is proposed that {\em any} boundary condition that is finite everywhere leads to a solution which is also finite everywhere. This explains the $(1,D-1)$ signature of the metric, the boundedness of energy from below, the absence of tachyons, and other related properties of nature. The time arrow is explained by proposing that the boundary condition should be ordered. The quantization is considered as a boundary condition for field operators. Only the physical degrees of freedom are quantized.
description: 22 pages. I have written the first version (v1) 20+ years ago when I was young and bold, but then forgotten it and worked on other stuff. Now with some maturity I have looked at it again and concluded that it is still worth publication, with a minimal revision. The reviewers and editors of Symmetry agreed
Continuum Halos in Nearby Galaxies -- an EVLA Survey (CHANG-ES) -- II: First Results on NGC 4631
Creators: name: Irwin, Judith
name: Beck, Rainer
name: Benjamin, R. A.
name: Dettmar, Ralf-Juergen
name: English, Jayanne
name: Heald, George
name: Henriksen, Richard N.
name: Johnson, Megan
name: Krause, Marita
name: Li, Jiang-Tao
name: Miskolczi, Arpad
name: Mora, Silvia Carolina
name: Murphy, E. J.
name: Oosterloo, Tom
name: Porter, Troy A.
name: Rand, Richard J.
name: Saikia, D. J.
name: Schmidt, Philip
name: Strong, A. W.
name: Walterbos, Rene
name: Wang, Q. Daniel
name: Wiegert, Theresa
Publisher: name: arXiv
Year: 2012
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We present the first results from the CHANG-ES survey, a new survey of 35 edge-on galaxies to search for both in-disk as well as extra-planar radio continuum emission. The motivation and science case for the survey are presented in a companion paper (Paper I). In this paper (Paper II), we outline the observations and data reduction steps required for wide-band calibration and mapping of EVLA data, including polarization, based on C-array test observations of NGC 4631. With modest on-source observing times (30 minutes at 1.5 GHz and 75 minutes at 6 GHz for the test data) we have achieved best rms noise levels of 22 and 3.5 $μ$Jy beam$^{-1}$ at 1.5 GHz and 6 GHz, respectively. New disk-halo features have been detected, among them two at 1.5 GHz that appear as loops in projection. We present the first 1.5 GHz spectral index map of NGC 4631 to be formed from a single wide-band observation in a single array configuration. This map represents tangent slopes to the intensities within the band centered at 1.5 GHz, rather than fits across widely separated frequencies as has been done in the past and is also the highest spatial resolution spectral index map yet presented for this galaxy. The average spectral index in the disk is $\barα_{1.5 GHz}\,=\,-0.84\,\pm\,0.05$ indicating that the emission is largely non-thermal, but a small global thermal contribution is sufficient to explain a positive curvature term in the spectral index over the band. Two specific star forming regions have spectral indices that are consistent with thermal emission. Polarization results (uncorrected for internal Faraday rotation) are consistent with previous observations and also reveal some new features. On broad scales, we find strong support for the notion that magnetic fields constrain the X-ray emitting hot gas.
description: Accepted to the Astronomical Journal, Version 2 changes: Added acknowledgement to NRAO
Bohman-Frieze-Wormald model on the lattice, yielding a discontinuous percolation transition
Creators: name: Schrenk, K. J.
name: Felder, A.
name: Deflorin, S.
name: Araújo, N. A. M.
name: D'Souza, R. M.
name: Herrmann, H. J.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: The BFW model introduced by Bohman, Frieze, and Wormald [Random Struct. Algorithms, 25, 432 (2004)] and recently investigated in the framework of discontinuous percolation by Chen and D'Souza [Phys. Rev. Lett., 106, 115701 (2011)], is studied on the square and simple-cubic lattices. In two and three dimensions, we find numerical evidence for a strongly discontinuous transition. In two dimensions, the clusters at the threshold are compact with a fractal surface of fractal dimension $d_f=1.49\pm0.02$. On the simple-cubic lattice, distinct jumps in the size of the largest cluster are observed. We proceed to analyze the tree-like version of the model, where only merging bonds are sampled, for dimension two to seven. The transition is again discontinuous in any considered dimension. Finally, the dependence of the cluster-size distribution at the threshold on the spatial dimension is also investigated.
Sensor-based Temporal Superresolution: Application to turbulent separated flow over a three-dimensional Gaussian hill
Creators: name: Manohar, Kevin Harsh
Publisher: name: Graduate Studies
Year: 2023
Subjects: subject: Turbulent separated flows
subject: Machine learning
subject: Sensor fusion
subject: Superresolution
subject: Engineering--Aerospace
subject: Engineering--Mechanical
subject: Fluid and Plasma

description: The high Reynolds-number turbulent separated flow over a Gaussian speed-bump benchmark geometry presents challenges for predicting smooth-body flow separation. The lack of time-resolved experimental data further hampers the understanding of the three-dimensional unsteady dynamics. This thesis addresses these issues in two parts. First, a data-driven technique using high-rate surface-pressure sensors and long short-term memory (LSTM) neural networks is proposed to estimate aliased velocity dynamics from undersampled particle image velocimetry (PIV) data, revealing low and medium-frequency modes. Second, the three-dimensional unsteady wake dynamics is characterized using additional surface-pressure measurements and two-component PIV. Four dominant frequencies are identified, with a very low-frequency spanwise oscillation of the recirculating zone, two low frequencies associated with the primary separation front motion, and a higher frequency from shear layer vortex shedding. Proper orthogonal decomposition analysis highlights interactions between these modes. The instantaneous vortex topology is conceptualized to infer physical mechanisms that give rise to these frequencies.
Optimization and characterization of integrated cooling circuit for gas turbine cooling
Creators: name: Yoon, Christopher
Publisher: name: The University of Texas at Austin
Year: 2022
Subjects: Gas turbine
Film cooling
Internal cooling
Adiabatic effectiveness
Overall 3ffectiveness
Optimization
Serpentine channel
Rib turbulators
CFD
Experimental study

description: The objective of this research was to optimize the integrated design of internal cooling and film cooling configuration for a gas turbine airfoil. Various film cooling hole geometries were tested with appropriate co-flow and counter-flow channel feed configurations in the wind tunnel facility. The results showed that X-AOpt hole, a shaped film cooling hole which had been previously developed in our laboratory using a computational adjoint optimization technique, outperformed all other geometries in adiabatic effectiveness. In terms of peak performance, X-AOpt hole was able to perform 70% better than the reference 7-7-7 hole. Thermal field measurements showed that the film cooling jets of the X-AOpt hole were better attached to the surface, showing little signs of separation. However, one drawback of the X-AOpt hole was that it showed significant hole-to-hole variation in co-flow and counter-flow tests. Next, computational simulations and experimental tests were run with serpentine channels. This part of the study investigated the optimum internal rib configuration to be used with a serpentine channel. Three rib configurations were considered: -60°, 90°, and +60° ribs. Computational simulations predicted that -60° ribs would reduce pressure drop compared to the smooth channel. Flow field visualization showed that large separation regions after each U-bend were responsible for increasing the pressure drop for the smooth serpentine channel, and the -60◦ ribs helped to redistribute the biased flow. Experiments showed that the pressure drop of the smooth serpentine channel was over-predicted, and the actual pressure drop between smooth and -60° rib case were similar. However, +60° ribs significantly increased the pressure drop, consistent with CFD predictions. In terms of heat transfer, both CFD predictions and experiments showed that there was no noticeable change in surface temperatures. Adiabatic effectiveness measurements with X-AOpt holes under cross-flow were also evaluated. The X-AOpt holes showed good hole-to-hole uniformity when operating in cross-flow. The spatially-averaged adiabatic effectiveness continued to increase with increasing film injection rates, eventually surpassing the performance of the same holes operating under co-flow and counter-flow at high injection rates. In terms of overall-effectiveness, the X-AOpt holes in serpentine channels showed 30% better effectiveness than co-flow channel tests.
Measurement and Control of Single Nitrogen-Vacancy Center Spins above 600 K
Creators: name: Toyli, D. M.
name: Christle, D. J.
name: Alkauskas, A.
name: Buckley, B. B.
name: Van de Walle, C. G.
name: Awschalom, D. D.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study the spin and orbital dynamics of single nitrogen-vacancy (NV) centers in diamond between room temperature and 700 K. We find that the ability to optically address and coherently control single spins above room temperature is limited by nonradiative processes that quench the NV center's fluorescence-based spin readout between 550 and 700 K. Combined with electronic structure calculations, our measurements indicate that the energy difference between the 3E and 1A1 electronic states is approximately 0.8 eV. We also demonstrate that the inhomogeneous spin lifetime (T2*) is temperature independent up to at least 625 K, suggesting that single NV centers could be applied as nanoscale thermometers over a broad temperature range.
description: 8 pages, 5 figures, and 14 pages of supplemental material with additional figures. Title change and minor revisions from previous version. DMT and DJC contributed equally to this work
Reduction of mean-square advection in turbulent passive scalar mixing
Creators: name: Bos, Wouter J. T.
name: Rubinstein, Robert
name: Fang, Le
Publisher: name: arXiv
Year: 2011
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: Direct numerical simulation data show that the variance of the coupling term in passive scalar advection by a random velocity field is smaller than it would be if the velocity and scalar fields were statistically independent. This effect is analogous to the "depression of nonlinearity" in hydrodynamic turbulence. We show that the trends observed in the numerical data are qualitatively consistent with the predictions of closure theories related to Kraichnan's direct interaction approximation. The phenomenon is demonstrated over a range of Prandtl numbers. In the inertial-convective range the depletion is approximately constant with respect to wavenumber. The effect is weaker in the Batchelor range.
Fully Integrated GaN Front-End RF Modules for Advanced Spaceborne Synthetic Aperture Radars
Creators: name: Shekari Beyragh, Dawood
Publisher: name: Graduate Studies
Year: 2023
Subjects: subject: Front-End Module
subject: Synthetic Aperture Radar
subject: GaN HEMT Technology
subject: RF Switch
subject: T/R Switch
subject: Engineering--Electronics and Electrical

description: RF front-end modules (FEMs) are vital in wireless communication and radar systems. FEMs comprise three fundamental components: a power amplifier (PA), a low noise amplifier (LNA), and a T/R switch. PAs use the highest power in wireless communication and radar systems and, jointly with the T/R switches, are responsible for most dissipations and heat generation. So, developing higher efficiency architectures for the PAs and T/R switches is crucial for reducing power consumption, extending the battery lifetime of the mobile systems, reducing the operating temperature, and improving reliability. Besides, new wireless communication applications, like 5G NR, and spaceborne synthetic aperture radars (SAR), demand FEMs with higher output power and operating frequency. Realizing these new applications using mature semiconductor technologies like Si and GaAs technologies is becoming more and more challenging while using GaN technology shows a prominent figure of merits. This thesis proposes two novel high-power GaN-based T/R switch architectures for spaceborne synthetic aperture radar applications. Then it describes the design process for three switches operating in C and X bands based on the proposed architectures using United Monolithic Semiconductors (UMS) GH25-10 0.25 μm GaN HEMT process. The designed switches’ simulation and measurement results are presented, showing a good agreement and verifying the desired performance of the proposed architectures. The second part of the thesis describes the development of a fully integrated C-band FEM using one of the designed switches, a PA, and an LNA developed in iRadio Lab. Due to the contractual requirements, asking for on-wafer testing of each FEM building block as a standalone component, these blocks were implemented with 50 Ω ports to be interconnected later when evaluating the full FEM performance. The on-wafer experimental results of the FEM individual building blocks show good agreement with the simulation results. As the last part, a breadboard was designed to assess the performance of the FEM in realistic operating conditions, and an on-wafer, low-loss, 50 Ω high-power interconnection method was developed to interconnect the T/R switch to the HPA and LNA. The breadboard measurement results agree with the interconnected FEM simulation results and show the outstanding performance of the FEM under large-signal conditions.
Renormalization persistency of tensor force in nuclei
Creators: name: Tsunoda, Naofumi
name: Otsuka, Takaharu
name: Tsukiyama, Koshiroh
name: Hjorth-Jensen, Morten
Publisher: name: arXiv
Year: 2011
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: In this work we analyze the tensor-force component of effective interactions appropriate for nuclear shell-model studies, with particular emphasis on the monopole term of the interactions. Standard nucleon-nucleon ($NN$) interactions such as AV8' and $χ$N$^3$LO are tailored to shell-model studies by employing $V_{low k}$ techniques to handle the short-range repulsion of the $NN$ interactions and by applying many-body perturbation theory to incorporate in-medium effects. We show, via numerical studies of effective interactions for the $sd$ and $pf$ shells, that the tensor-force contribution to the monopole term of the effective interaction is barely changed by these renormalization procedures, resulting in almost the same monopole term as the one of the bare $NN$ interactions. We propose to call this feature {\it Renormalization Persistency} of the tensor force, as it is a remarkable property of the renormalization and should have many interesting consequences in nuclear systems. For higher multipole terms, this feature is maintained to a somewhat smaller extent. We present general intuitive explanations for the renormalization persistency of the tensor force, as well as analyses of core-polarization terms in perturbation theory. The central force does not exhibit a similar renormalization persistency.
description: 13 pages, 8 figures
Much Ado About Nothing: A Director’s Reflection on Staging Shakespeare for Contemporary Audiences
Creators: name: Sproule, Cali
Publisher: name: Arts
Year: 2023
Subjects: subject: Directing
subject: Shakespeare
subject: Theatre
subject: Theater

description: This thesis is an artist's statement that is a cumulative reflection on the process of staging and directing William Shakespeare’s Much Ado About Nothing. This show was produced by the University of Calgary’s School of Creative and Performing Arts and was supervised by Professor Christine Brubaker. The first chapter introduces the play and explores the question “Why Shakespeare, Why Now?”. The second chapter explores preparation, artistic research and analysis. The third chapter reflects on collaboration and creativity, with a focus on design and the rehearsal process. The fourth chapter outlines a research study I enfolded into the rehearsal process which investigates consent-based rehearsal processes in university theatre training. The fifth chapter examines my experience of artistic leadership as a woman and outlines my values. The sixth chapter concludes by documenting a synthesis of my learnings and final reflections.
Landing together: how flocks arrive at a coherent action in time and space in the presence of perturbations
Creators: name: Ferdinandy, Bence
name: Bhattacharya, Kunal
name: Abel, Daniel
name: Vicsek, Tamas
Publisher: name: arXiv
Year: 2012
Subjects: subject: Biological Physics (physics.bio-ph)
subject: FOS: Physical sciences

description: Collective motion is abundant in nature, producing a vast amount of phenomena which have been studied in recent years, including the landing of flocks of birds. We investigate the collective decision making scenario where a flock of birds decides the optimal time of landing in the absence of a global leader. We introduce a simple phenomenological model in the spirit of the statistical mechanics-based self-propelled particles (SPP-s) approach to interpret this process. We expect that our model is applicable to a larger class of spatiotemporal decision making situations than just the landing of flocks (which process is used as a paradigmatic case). In the model birds are only influenced by observable variables, like position and velocity. Heterogeneity is introduced in the flock in terms of a depletion time after which a bird feels increasing bias to move towards the ground. Our model demonstrates a possible mechanism by which animals in a large group can arrive at an egalitarian decision about the time of switching from one activity to another in the absence of a leader. In particular, we show the existence of a paradoxical effect where noise enhances the coherence of the landing process.
description: 15 pages, 7 figures
Long-term cardiorespiratory, exercise intolerance and autonomic nervous system outcomes following adolescent sport-related concussion
Creators: name: Carere, Joseph
Publisher: name: Graduate Studies
Year: 2023
Subjects: subject: Sport-related concussion
subject: Adolescent
subject: Autonomic nervous system
subject: Cardiorespiratory fitness
subject: Exercise intolerance
subject: Physiology
subject: FOS: Biological sciences
subject: Long-term outcomes
subject: Health Sciences

description: Adolescents experience high rates of sport related concussion (SRC) and are neurologically vulnerable. There is a paucity of research examining long-term physiological outcomes following adolescent SRC. This thesis compared cardiorespiratory, exercise intolerance, and autonomic nervous system (ANS) outcomes 5-15-years prior to study enrolment for individuals who sustained an adolescent SRC (SRC), a sport-related musculoskeletal injury (MSK), or played adolescent sport and went uninjured (CON). Data was collected for 156 participants (50 CON; 52 MSK; 54 SRC). Study findings suggest cardiorespiratory fitness and ANS function were generally robust to SRC, though prolonged concussion-related symptoms led to heightened discomfort during physical activity in a small subset of participants. Overall, these findings are encouraging when considering adolescent sport participation. They demonstrate that ANS and cardiorespiratory fitness are generally robust in the long-term to SRC sustained during this important neurodevelopment period. Future research should investigate physiological outcomes in those with persistent symptoms.
The size of the jet launching region in M87
Creators: name: Dexter, Jason
name: McKinney, Jonathan C.
name: Agol, Eric
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The supermassive black hole candidate at the center of M87 drives an ultra-relativistic jet visible on kiloparsec scales, and its large mass and relative proximity allow for event horizon scale imaging with very long baseline interferometry at millimeter wavelengths (mm-VLBI). Recently, relativistic magneto-hydrodynamic (MHD) simulations of black hole accretion flows have proven capable of launching magnetically-dominated jets. We construct time-dependent disc/jet models of the innermost portion of the M87 nucleus by performing relativistic radiative transfer calculations from one such simulation. We identify two types of models, jet-dominated or disc/jet, that can explain the spectral properties of M87, and use them to make predictions for current and future mm-VLBI observations. The Gaussian source size for the favored sky orientation and inclination from observations of the large-scale jet is 33-44 microarcseconds (~4-6 Schwarzschild radii) on current mm-VLBI telescopes, very similar to existing observations of Sgr A*. The black hole shadow, direct evidence of an event horizon, should be visible in future measurements using baselines between Hawaii and Mexico. Both models exhibit variability at millimeter wavelengths with factor of ~2 amplitudes on year timescales. For the low inclination of M87, the counter-jet dominates the event horizon scale millimeter wavelength emission from the jet-forming region.
description: 13 pages, 10 figures, MNRAS in press. Minor changes from original version
Connected-Sea Partons
Creators: name: Liu, Keh-Fei
name: Chang, Wen-Chen
name: Cheng, Hai-Yang
name: Peng, Jen-Chieh
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Lattice (hep-lat)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: According to the path-integral formalism of the hadronic tensor, the nucleon sea contains two distinct components called connected sea (CS) and disconnected sea (DS). We discuss how the CS and DS are accessed in the lattice QCD calculation of the moments of the parton distributions. We show that the CS and DS components for $\bar u(x) + \bar d(x)$ can be extracted by using recent data on the strangeness parton distribution, the CT10 global fit, and the lattice result of the ratio of the strange to $u(d)$ moments in the disconnected insertion. The extracted CS and DS for $\bar u(x) + \bar d(x)$ have distinct Bjorken $x$ dependence in qualitative agreement with expectation. The analysis also shows that the momentum fraction of the $\bar u(x) + \bar d(x)$ is about equally divided between CS and DS at $Q^2 = 2.5 {\rm GeV}^2$. Implications on future global analysis for parton distributions are presented.
description: Revised version to be published in Phys. Rev. Lett
Revictimization from Childhood to Adulthood and Disordered Eating in Women
Creators: name: Nieborowska, Victoria
Publisher: name: Werklund School of Education
Year: 2023
Subjects: subject: Educational Psychology
subject: Psychology--Clinical
subject: Mental Health

description: Revictimization, defined as risk for and those who have experienced subsequent trauma following initial trauma exposure, has been gaining research attention due to its myriad of psychological consequences; however, less is known about its link with disordered eating. Women are particularly vulnerable to both revictimization and disordered eating. The purpose of this dissertation study was to investigate the association between revictimization from childhood to adulthood and disordered eating among women and the mediating role of posttraumatic stress symptoms (PTSS) and complex posttraumatic symptoms (CPTSS) in these relationships. As difficulties in emotion regulation are implicated in disordered eating and trauma symptoms, it was also examined whether the link between revictimization, trauma-related symptoms, and disordered eating were stronger if women exhibited higher emotion regulation impairment. This was assessed by conducting moderated mediation using structural equation modelling (SEM). A total sample of 563 women between 19 to 65 years of age were recruited from an online research participation platform (Prolific) and completed an online survey comprised of several self-report measures, such as the Difficulties in Emotion Regulation Scale – Short Form, Eating Disorder Examination Questionnaire, International Trauma Questionnaire, and a victimization and revictimization questionnaire created for this study. Results of the SEM moderated mediation analysis found that revictimization was significantly associated with higher disordered eating in women. The findings also indicated that CPTSS mediated the link between revictimization and disordered eating, while emotion regulation did not moderate the pathways from revictimization to CPTSS and CTPSS to disordered eating. Post-hoc analyses revealed that emotion regulation difficulties significantly mediated the effects of revictimization on disordered eating. Together, these findings highlight the need for more integrated evidence-based interventions to address revictimization and disordered eating in women with such comorbid presentations.
Questionable Metascience Practices
Creators: name: Rubin, Mark
Publisher: name: figshare
Year: 2023
Subjects: Other psychology not elsewhere classified

description: Metascientists have studied questionable research practices in science. The present article considers the parallel concept of questionable metascience practices (QMPs). A QMP is a research practice, assumption, or perspective that has been questioned by several commentators as being potentially problematic for metascience and/or the science reform movement. The present article reviews ten QMPs that relate to criticism, replication, bias, generalization, and the characterization of science. Specifically, the following QMPs are considered: (1) rejecting or ignoring self-criticism; (2) a fast ‘n’ bropen scientific criticism style; (3) overplaying the role of replication in science; (4) assuming a replication rate is “too low” without specifying an “acceptable” rate; (5) an unacknowledged metabias towards explaining the replication crisis in terms of researcher bias; (6) assuming that researcher bias can be reduced; (7) devaluing exploratory results as being more “tentative” than confirmatory results; (8) presuming that questionable research practices are problematic research practices; (9) focusing on knowledge accumulation; and (10) focusing on specific scientific methods. It is stressed that only some metascientists engage in some QMPs some of the time, and that these QMPs may not always be problematic. Research is required to estimate the prevalence and impact of QMPs. In the meantime, QMPs should be viewed as invitations to ask questions about how we go about doing better metascience.
Vector bundles of rank four and A_3 = D_3
Creators: name: Auel, Asher
Publisher: name: arXiv
Year: 2011
Subjects: subject: Algebraic Geometry (math.AG)
subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 14L35, 11E57, 19G12, 14D20, 11E81, 14L15

description: Over a scheme with 2 invertible, we show that a vector bundle of rank four has a sub or quotient line bundle if and only if the canonical symmetric bilinear form on its exterior square has a lagrangian subspace. For this, we exploit a version of "Pascal's rule" for vector bundles that provides an explicit isomorphism between the moduli functors represented by projective homogeneous bundles for reductive group schemes of type A_3 and D_3. Under additional hypotheses on the scheme (e.g. proper over a field), we show that the existence of sub or quotient line bundles of a rank four vector bundle is equivalent to the vanishing of its Witt-theoretic Euler class.
description: 16 pages, final version; IMRN 2012 rns140
Exposed positive maps: a sufficient condition
Creators: name: Chruściński, Dariusz
name: Sarbicki, Gniewomir
Publisher: name: arXiv
Year: 2011
Subjects: subject: Quantum Physics (quant-ph)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: Exposed positive maps in matrix algebras define a dense subset of extremal maps. We provide a sufficient condition for a positive map to be exposed. This is an analog of a spanning property which guaranties that a positive map is optimal. We analyze a class of decomposable maps for which this condition is also necessary.
description: 10 pages; improved version
A comprehensive study on the relationship between image quality and imaging dose in low-dose cone beam CT
Creators: name: Yan, Hao
name: Cervino, Laura
name: Jia, Xun
name: Jiang, Steve B.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Medical Physics (physics.med-ph)
subject: FOS: Physical sciences

description: While compressed sensing (CS) based reconstructions have been developed for low-dose CBCT, a clear understanding on the relationship between the image quality and imaging dose at low dose levels is needed. In this paper, we qualitatively investigate this subject in a comprehensive manner with extensive experimental and simulation studies. The basic idea is to plot image quality and imaging dose together as functions of number of projections and mAs per projection over the whole clinically relevant range. A clear understanding on the tradeoff between image quality and dose can be achieved and optimal low-dose CBCT scan protocols can be developed for various imaging tasks in IGRT. Main findings of this work include: 1) Under the CS framework, image quality has little degradation over a large dose range, and the degradation becomes evident when the dose < 100 total mAs. A dose < 40 total mAs leads to a dramatic image degradation. Optimal low-dose CBCT scan protocols likely fall in the dose range of 40-100 total mAs, depending on the specific IGRT applications. 2) Among different scan protocols at a constant low-dose level, the super sparse-view reconstruction with projection number less than 50 is the most challenging case, even with strong regularization. Better image quality can be acquired with other low mAs protocols. 3) The optimal scan protocol is the combination of a medium number of projections and a medium level of mAs/view. This is more evident when the dose is around 72.8 total mAs or below and when the ROI is a low-contrast or high-resolution object. Based on our results, the optimal number of projections is around 90 to 120. 4) The clinically acceptable lowest dose level is task dependent. In our study, 72.8mAs is a safe dose level for visualizing low-contrast objects, while 12.2 total mAs is sufficient for detecting high-contrast objects of diameter greater than 3 mm.
description: 19 pages, 12 figures, submitted to Physics in Medicine and Biology
School Psychology and COVID-19 in Canada: Turning crisis into opportunities
Creators: name: Portela, Natasha Cabrera Piñeiro
Publisher: name: Graduate Studies
Year: 2023
Subjects: subject: COVID-19
subject: School Psychology
subject: Post-COVID-19
subject: Adaptations AND Challenges
subject: Canada
subject: Educational Psychology
subject: Education
subject: Education--Health

description: The Coronavirus 2019 (COVID-19) caused a significant crisis for the educational system and its students worldwide. School psychologists were among the many professionals who adapted their work to meet the needs of schools and students during the pandemic. This study aimed to gain a deeper understanding of school psychologists’ experiences regarding the changes and adaptations in their practices during COVID-19 and evaluate their perceptions of the challenges and benefits associated with these changes. Another goal was to investigate their thoughts on what should be preserved, modified, or improved in the field. Twenty school psychologists working in schools across Canada were interviewed online using a modified version of the semi-structured interview developed by Reupert et al. (2022b). Interviews were transcribed and analyzed using reflexive thematic analysis. Six themes were identified, including (a) disruptions and challenges in services, (b) making it work - adapting one’s work, (c) coping with change - influences of work support & personal strategies, (d) effects of the COVID-19 pandemic on students, (e) school psychology work post-COVID-19, and (f) lessons learned and recommendations for future pandemics. This study aims to be of educational and practical significance to school psychologists. It is critical that we learn from this challenging period imposed by the COVID-19 crisis and identify what should be preserved or modified in Canadian school psychologists' practice post-pandemic.
Declamation in seventeenth-century English opera, or the nature of "recitative musick"
Creators: name: Henderlight, Justin
Publisher: name: University of British Columbia
Year: 2012

description: During the English Reformation, composers attempted to create a uniquely English take on opera, one rooted in dramatic elements and conventions tied to the English court masque of the earlier part of the century. One component essential to opera, recitative, was understood then and now to be an Italian invention, and though the Britons knew it to be an indispensible element of operatic style, they had only a passing acquaintance with its specific characteristics. Using stylistic features present in declamatory lutesongs from within masques and without, English composers attempted to develop their own brand of musical monody to fulfill the dramatic function of recitative in their operas. Traditionally, the stunted growth of this tradition has been explained by cultural and political factors alone; however, this study shows how the difficulties encountered while developing an English recitative tradition prevented composers from having the tools necessary for their operas to flourish. This fact is shown by examining the obstacles that had to be overcome when attempting to reconcile a rich, existing tradition of dramatic poetry with the demands of creating a moving and varied musical setting of the text. Further, an attempt is made to define the genre of English recitative and the breadth of style therein by examining the specific features of declamation in the major operatic works of Restoration England. The analysis further shows how the inconsistent degree of efficacy in these composers’ efforts prevented them from creating a conventionalized style of declamation applicable to all dramatic situations.
Microscopic coexistence of antiferromagnetic order and superconductivity in Ba$_{0.77}$K$_{0.23}$Fe$_{2}$As$_{2}$
Creators: name: Li, Z.
name: Zhou, R.
name: Sun, D. L.
name: Yang, J.
name: Lin, C. T.
name: Zheng, Guo-qing
Publisher: name: arXiv
Year: 2012
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We report ^{75}As nuclear magnetic resonance studies on an underdoped single-crystal Ba0.77K0.23Fe2As2 with Tc = 16.5 K. Below T_N = 46 K, the NMR peaks for H//c split and those for H //a shift to higher frequencies, which indicates that an internal magnetic field along the c axis develops below T_N. The spin-lattice relaxation rate 1/T_1 measured at the shifted peak with H//a, which experiences the internal field, shows a distinct decrease below Tc(μ_0H = 12 T) = 16 K, following a T^3 relation at low temperatures. Our results show unambiguously that antiferromagnetic order and superconductivity coexist microscopically. The unusual superconducting state with the coexisting magnetism is highlighted.
description: Editor's suggestion of PRB
Short-Range Correlations and Cooling of Ultracold Fermions in the Honeycomb Lattice
Creators: name: Tang, Baoming
name: Paiva, Thereza
name: Khatami, Ehsan
name: Rigol, Marcos
Publisher: name: arXiv
Year: 2012
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We use determinantal quantum Monte Carlo simulations and numerical linked-cluster expansions to study thermodynamic properties and short-range spin correlations of fermions in the honeycomb lattice. We find that, at half filling and finite temperatures, nearest-neighbor spin correlations can be stronger in this lattice than in the square lattice, even in regimes where the ground state in the former is a semimetal or a spin liquid. The honeycomb lattice also exhibits a more pronounced anomalous region in the double occupancy that leads to stronger adiabatic cooling than in the square lattice. We discuss the implications of these findings for optical lattice experiments.
description: 5 pages, 4 figures
Improved Basecalling and Base Modification Detection Through Signal-level Analysis of Nanopore Direct RNA Data
Creators: name: Wang, Scott
Publisher: name: Graduate Studies
Year: 2023
Subjects: subject: Nanopore
subject: Basecalling
subject: SARS-CoV-2
subject: RNA virus
subject: Bioinformatics
subject: FOS: Computer and information sciences

description: Genome sequencing technologies emerged as an essential tool for addressing challenges presented by the natural biological complexity of organisms. Unlike traditionally used next-generation sequencing (NGS) methods, which yield short reads, Third-generation sequencing (TGS) methods can sequence transcripts and complete genomes in single contiguous sequencing reads, providing innovative means to address practical topics surrounding viral transmission, evolution, and pathogenesis. TGS alleviates the computational challenges of consensus genome assembly or transcript construction from fragmented reads as required with building NGS libraries. Despite these advantages, as an emerging technology, TGS faces many technical challenges. High error rates make it difficult to distinguish machine errors from low frequency mutations in the genome. Some of the most well known and pervasive diseases in society originate from viruses with ribonucleic acid (RNA) genomes; these include but are not limited to Influenza and Coronaviruses. Advancement towards a comprehensive understanding of RNA viruses has been hindered by their unique biology and high levels of diversity, along with quick replication and mutation rates, which leads to important viral evolutionary signals in individual viral copies. Some of the high basecalling error rate in TGS can be attributed to the presence of unmodeled signal, e.g. calling just the four canonical nucleobases (A, C, G, T/U) when methylation along with other nucleobase modifications are also contributing to the signal. Being able to accurately identify (i.e. signal model) the location of such nucleobase modifications would naturally lead to better nucleobase calling and provide insights into RNA virus biology. The few extant tools in this area for TGS are based on deep-learning AI methods due to computational tractability, and are demonstrably biased. In contrast to such opaque methods, in this work, new efficient implementations of theoretically optimal (“dynamic programming”) methods for Oxford Nanopore Technologies (ONT) TGS raw signal segmentation, alignment, clustering, and consensus are deployed. With follow-on statistical analyses of signal deviations within those results, this defines a minimally biased, statistically grounded procedure for detecting unmodeled signal (i.e. putative nucleobase modifications or mutations), as demonstrated using multiple publicly available raw ONT direct RNA sequencing viral datasets.