cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
The "99%" versus Neoliberal Elites?: A Fraserian Analysis of Occupy
Creators: name: Brosh, Caleb
Publisher: name: Graduate Studies
Year: 2016
Subjects: Education--Social Sciences

description: This is a theoretical research project that focuses on social justice within the American Occupy movement. This thesis reconceives Occupy using Nancy Fraser’s three-dimensional theory of social and global justice. Fraser’s dimensions of justice – economic redistribution, cultural recognition, and political representation – will be used to evaluate whether or not Occupy can achieve meaningful social justice. This project delves deeper into the individualist and populist underpinnings of Occupy, proposes more appropriate alternatives, and applies the findings from the Occupy movement to the larger global justice movement.
Strategies for Improving the Productivity and Cost-effectiveness of Microalgal Production Systems
Creators: name: Canon-Rubio, Karen Andrea
Publisher: name: Graduate Studies
Year: 2016
Subjects: subject: Engineering
subject: Engineering--Chemical
subject: Engineering--Environmental
subject: Microalgal productivity
subject: Alkaliphiles
subject: Mixotrophic cultivation
subject: Bioenergy
subject: CO2 Capture

description: Microalgae cultivation is a potential solution for renewable energy supply issues and environmental remediation; however, low CO2 absorption rates and volumetric productivities restrain commercial application of algal biotechnology. Mixotrophic and high-alkalinity/high-pH approaches for improving the productivity and cost-effectiveness were evaluated. Although mixotrophic cultivation of Chlamydomonas reinhardtii at low light exposure and high inoculum concentrations showed an improvement in biomass productivity (0.080±0.057 g/L·d in phototrophic experiments versus 0.44±0.163 g/L·d in mixotrophic experiments), values were not sufficient to improve performance of large scale microalgal technology. On the other hand, the high-alkalinity/high-pH approach showed a better performance in terms of lower use of resources and smaller equipment size reflected in three-fold less water requirements, twice the energy return on energy investment (EROI) and four-fold lower production costs (8.03 to 1.63 2013 US$/kg biomass). Economic and environmental results highlight the potential of high–alkalinity/high-pH systems in terms of productivity and cost-effectiveness of microalgal technology.
Solutions of Several Coupled Discrete Models in terms of Lame Polynomials of Arbitrary Order
Creators: name: Khare, Avinash
name: Saxena, Avadh
name: Khare, Apoorva
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: Coupled discrete models abound in several areas of physics. Here we provide an extensive set of exact quasiperiodic solutions of a number of coupled discrete models in terms of Lamé polynomials of arbitrary order. The models discussed are (i) coupled Salerno model, (ii) coupled Ablowitz-Ladik model, (iii) coupled $ϕ^4$ model, and (iv) coupled $ϕ^6$ model. In all these cases we show that the coefficients of the Lamé polynomials are such that the Lamé polynomials can be reexpressed in terms of Chebyshev polynomials of the relevant Jacobi elliptic function.
Measurement and Calibration of Noise Bias in Weak Lensing Galaxy Shape Estimation
Creators: name: Kacprzak, Tomasz
name: Zuntz, Joe
name: Rowe, Barnaby
name: Bridle, Sarah
name: Refregier, Alexandre
name: Amara, Adam
name: Voigt, Lisa
name: Hirsch, Michael
Publisher: name: arXiv
Year: 2012
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Weak gravitational lensing has the potential to constrain cosmological parameters to high precision. However, as shown by the Shear TEsting Programmes (STEP) and GRavitational lEnsing Accuracy Testing (GREAT) Challenges, measuring galaxy shears is a nontrivial task: various methods introduce different systematic biases which have to be accounted for. We investigate how pixel noise on the image affects the bias on shear estimates from a Maximum-Likelihood forward model-fitting approach using a sum of co-elliptical Sérsic profiles, in complement to the theoretical approach of an an associated paper. We evaluate the bias using a simple but realistic galaxy model and find that the effects of noise alone can cause biases of order 1-10% on measured shears, which is significant for current and future lensing surveys. We evaluate a simulation-based calibration method to create a bias model as a function of galaxy properties and observing conditions. This model is then used to correct the simulated measurements. We demonstrate that this method can effectively reduce noise bias so that shear measurement reaches the level of accuracy required for estimating cosmic shear in upcoming lensing surveys.
description: 12 pages, 4 figures, submitted to MNRAS
Elections in authoritarian regimes : an endogenous story of elite dynamics in post reform Vietnam and China
Creators: name: Chan, Evelyn
Publisher: name: University of British Columbia
Year: 2010

description: The study of elections in authoritarian states has predominantly focused on whether elections help sustain or undercut the regime. Elections can either placate or embolden the opposition. However in the context of single party Leninist states, elections play a different role. Given that the Vietnamese Communist Party and the Chinese Communist Party have a monopoly of power in the political arena and tremendous control over society, there is no significant opposition force. Yet the two states hold elections. Furthermore, despite the two country’s similar trajectories of political and economic reform, both states undertake semi-competitive elections differently. China chooses to maintain a relatively closed system at the top, while creating a dynamic and competitive system at the local level; while Vietnam opts for a more open system at the top and keeps electoral institutions closed at the local level. This paper raises several questions; 1) why do Single Party Leninist States hold elections? 2) What is the significance of holding national versus sub-national elections? 3) why do China and Vietnam hold different types of elections given their similar regime-type? I propose an endogenous story to explain the varied outcomes in electoral institutions in China and Vietnam. Authoritarian elections and election-types are an institutional choice and a function of how the regime is constrained by elite pluralism. Comparing Vietnam and China and how they liberalize and cede power to institutions at different levels, demonstrates how elite divide shape the type of elections undertaken.
In-situ monitoring of groundwater radionuclides with emphasis on tritium
      detection
Creators: name: Alton, Tilly Lucy
Publisher: name: Lancaster University
Year: 2019
Subjects: Tritium
CaF2:Eu
Scintillator
Radiation detection
Beta Particles

description: This thesis is concerned with the detection of low energy beta emitting
      radioisotopes from a source of groundwater, with particular emphasis on
      tritium (3H). This is investigated firstly through
      an understanding of the challenges of detecting tritiated water, which
      involves the use of Monte Carlo simulations, numerical analysis and the
      development of simple scintillator-based detector system. Secondly, by a
      novel exploration of heterogeneous scintillators, utilising scintillator
      fabrication, Geant4 simulations and a refined detector prototype. And
      finally, by the design and testing of a flow cell detector based on the
      novel heterogeneous scintillator, including the detection of transient
      tritium concentration levels. The results have demonstrated that the beta
      particle in the tritiated water undergoes attenuation which causes a shift
      in the detected energy spectrum, which is particularly relevant for single
      crystal scintillator detectors used to discriminate radioisotopes by
      comparing beta spectra. The heterogeneous scintillator used was fabricated
      through a granulation method, before being used to validate simulations
      resulting in a novel heterogeneous scintillator configuration. The results
      of the flow cell and associated detection showed tentative validation of
      the theory, showing how a short detection time would impact on detector
      performance.
4D topology optimization: Integrated optimization of the structure and self-actuation of soft bodies for dynamic motions
Creators: name: Yuhn, Changyoung
name: Sato, Yuki
name: Kobayashi, Hiroki
name: Kawamoto, Atsushi
name: Nomura, Tsuyoshi
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computational Engineering, Finance, and Science (cs.CE)
subject: FOS: Computer and information sciences

description: Topology optimization is a powerful tool utilized in various fields for structural design. However, its application has primarily been restricted to static or passively moving objects, mainly focusing on hard materials with limited deformations and contact capabilities. Designing soft and actively moving objects, such as soft robots equipped with actuators, poses challenges due to simulating dynamics problems involving large deformations and intricate contact interactions. Moreover, the optimal structure depends on the object's motion, necessitating a simultaneous design approach. To address these challenges, we propose "4D topology optimization," an extension of density-based topology optimization that incorporates the time dimension. This enables the simultaneous optimization of both the structure and self-actuation of soft bodies for specific dynamic tasks. Our method utilizes multi-indexed and hierarchized density variables distributed over the spatiotemporal design domain, representing the material layout, actuator layout, and time-varying actuation. These variables are efficiently optimized using gradient-based methods. Forward and backward simulations of soft bodies are done using the material point method, a Lagrangian-Eulerian hybrid approach, implemented on a recent automatic differentiation framework. We present several numerical examples of self-actuating soft body designs aimed at achieving locomotion, posture control, and rotation tasks. The results demonstrate the effectiveness of our method in successfully designing soft bodies with complex structures and biomimetic movements, benefiting from its high degree of design freedom.
description: 36 pages, 27 figures; for supplementary video, see https://youtu.be/sPY2jcAsNYs
Novel Drug Discovery for Glioblastoma Multiforme Using Brain Tumour Initiating Cells
Creators: name: Nguyen, Stephanie
Publisher: name: Graduate Studies
Year: 2013
Subjects: subject: Molecular
subject: Neuroscience
subject: Oncology
subject: glioblastoma
subject: JAK/STAT3

description: Glioblastoma (GBM) is the most common and aggressive adult primary brain tumour. Populations of cells with tumour initiating capacity, termed brain tumour initiating cells (BTICs), are thought to underlie the formation, growth and recurrence of GBM. As such, therapies that target this compartment may improve the otherwise poor prognosis of this disease. Here, we identified R333, a compound targeting the JAK/STAT3 pathway, as a potent inhibitor of BTIC tumourigenicity. In vitro, R333 dramatically decreased the viability and clonogenic potential of diverse BTIC lines. In vivo, systemic treatment with R348, the prodrug form of R333, was well tolerated and demonstrated favourable pharmacokinetic properties. R348 treatment was also found to lead to a significant increase in overall median survival in an orthotopic BTIC xenograft model. Altogether, these data strongly support further investigation of this compound and potentially represent the first step toward an effective molecularly targeted therapeutic for GBM.
Force-Directed Partitioning Technique for 3D IC
Creators: name: Fakheri Tabrizi, Aysa
Publisher: name: Graduate Studies
Year: 2013
Subjects: subject: Engineering--Electronics and Electrical
subject: 3D ICs, Partitioning, Physical Design, Force-Directed, Simulated Annealing

description: 3D IC design is one of the challenging problems of today. 3D partitioning solutions can significantly impact manufacturability and performance of a circuit. In this work, a 3D partitioning technique is developed that reduces the number of TSVs by using force directed placement technique. A circuit is partitioned into several layers and a force directed placement problem is solved to find the optimal locations of the partitions. This partitioning solution is improved by using a proposed force-based simulated annealing technique. The proposed technique is tested on ISPD04 circuits, and shows up to 20% reduction in the number of TSVs.
Excited-State Studies with the Constricted Variational Density Functional Theory (CV-DF) Method
Creators: name: Seidu, Issaka
Publisher: name: Graduate Studies
Year: 2016
Subjects: subject: Chemistry--Inorganic
subject: Chemistry--Physical
subject: Mathematics
subject: FOS: Mathematics
subject: Physics--Molecular
subject: Density Functional Theory (DFT)
subject: Excitation
subject: Excited-state studies
subject: Transition metal
subject: CV-DFT
subject: Spin-flip
subject: ETS-NOCV
subject: Double elctron excitation
subject: Rydberg
subject: Charge-transfer
subject: Density

description: Theoretical calculations have played a vital role in understanding electronic properties of chemically and electronically relevant systems. Some of the roles played by theoretical approaches include the assignment and interpretation of spectra of chemical species such as the transition metal (TM) complexes. However, before these theoretical methods can be used as predictive tools in the chemical analysis of compounds for which experimental results are unavailable, the performance and scope of applicability of these methods must be well understood and improvements made wherever necessary. In this work, the Constricted Variational Density Functional Theory (CV-DFT) method is used in detailed analyses of excited-state properties of TM and other chemical species. Studies are carried out with the CV-DFT method in areas where the adiabatic Time-Dependent Density Functional Theory (ATD-DFT) method have been found insufficient, such as charge transfer (CT) and Rydberg excitations, as well as areas where ATD-DFT performed well. This was done to ensure that, the CV-DFT method not only show good performance for excitations poorly described by ATD-DFT but those that are sufficiently described as well. For a better understanding of the strengths and weaknesses of the CV-DFT methods, our calculated results are compared to experimental and/or high level ab initio results whenever available. Finally, an extension is made to CV-DFT for double excitation. These double excitations are known to be important for excited-state studies in conjugated systems such as the polyenes. Future work will be carried to examine the performance of this method. We find, in general, that CV-DFT shows accurate performance for excitations that are poorly described by the ATD-DFT method, and comparable performance for excitations in which ATD-DFT performs adequately.
The Neutral Hydrogen Bridge between M31 and M33
Creators: name: Lockman, Felix J.
name: Free, Nicole L.
name: Shields, Joseph C.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The Green Bank Telescope has been used to search for 21cm HI emission over a large area between the galaxies M31 and M33 in an attempt to confirm at 9.1 arcmin angular resolution the detection by Braun and Thilker (2004) of a very extensive neutral gas "bridge" between the two systems at the level NHI approximately 10^{17} cm^{-2}. We detect HI emission at several locations up to 120 kpc in projected distance from M31, at least half the distance to M33, with velocities similar to that of the galaxies, confirming the essence of the Braun and Thilker discovery. The HI does not appear to be associated with the extraplanar high-velocity clouds of either galaxy. In two places we measure NHI > 3 x 10^{18} cm^{-2}, indicative of concentrations of HI with ~10^5 solar masses on scales <2 kpc, but over most of the field we have only 5sigma upper limits of NHI <= 1.4 x 10^{18} cm^{-2}. In very deep measurements in two directions HI lines were detected at a few 10^{17} cm^{-2}. The absence of emission at another location to a 5sigma limit NHI <= 1.5 x 10^{17} cm^{-2} suggests that the HI bridge is either patchy or confined to within ~125 kpc of M31. The measurements also cover two of M31's dwarf galaxies, And II and And XV, but in neither case is there evidence for associated HI at the 5sigma level of 1.4 x 10^4 solar masses of HI for And II, and 9.3 x 10^3 solar masses for And XV.
description: Submitted to the Astronomical Journal
Double Double Electromagnetically Induced Transparency
Creators: name: Alotaibi, Hessa
Publisher: name: Graduate Studies
Year: 2015
Subjects: subject: Optics
subject: Nonlinear Optics
subject: Quantum Information
subject: Slow light
subject: Quantum Optics
subject: Electromagnetically Induced Transparency

description: This study demonstrates that tripod atom-field electronic structure can yield rich electromagnetically induced transparency phenomena, even at room temperature. In particular, we introduce double double electromagnetically induced transparency (DDEIT), wherein signal and probe fields each have two transparency windows. Their group velocities can be matched in either the first or second pair of transparency windows. Moreover, signal and probe fields can each experience coherent Raman gain in the second transparency window. Our investigation has demonstrated that the self-phase modulation (SPM) and cross-phase modulation (XPM) vanish at the center of two transparency windows for resonant coupling field. However, the values of the XPM and SPM in the region of the second EIT window are improved by a factor of $1000$ compared to their values in the region of the first EIT window under the same conditions, and have non-zero values at the center of the second EIT window for nonresonant coupling field. Additionally, we derive an analytical solution for the wave equation describing the propagation of the probe field whose amplitude-envelope function is described by the fundamental mode Laguerre-Gaussian function. Our solution exhibits that the group velocity of the probe field reduces as the field propagates through the medium. The group velocity reduction is a consequence of spatially-varying susceptibility. The variation of the susceptibility is established by employing signal field whose amplitude-envelope functions is also described by the fundamental mode Laguerre-Gaussian function. For Doppler-broadened media, we devise a scheme to control and reduce the probe-field group velocity at the center of the second transparency window. We derive numerical and approximate analytical solutions for the width of electromagnetically induced transparency (EIT) windows and for the group velocities of the probe field at the two distinct transparency windows, and we show that the group velocities of the probe field can be lowered by judiciously choosing the physical parameters of the system. Our modeling enables us to identify three signal-field strength regimes quantified by the Rabi frequency, for slowing the probe field. Our scheme exploits the fact that the second transparency window is sensitive to a temperature-controlled signal-field nonlinearity, whereas the first transparency window is insensitive to this nonlinearity.
A geometrically aware auto-encoder for multi-texture synthesis
Creators: name: Chatillon, Pierrick
name: Gousseau, Yann
name: Lefebvre, Sidonie
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: We propose an auto-encoder architecture for multi-texture synthesis. The approach relies on both a compact encoder accounting for second order neural statistics and a generator incorporating adaptive periodic content. Images are embedded in a compact and geometrically consistent latent space, where the texture representation and its spatial organisation are disentangled. Texture synthesis and interpolation tasks can be performed directly from these latent codes. Our experiments demonstrate that our model outperforms state-of-the-art feed-forward methods in terms of visual quality and various texture related metrics.
description: Error in table 1 corrected
The Design and Performance of IceCube DeepCore
Creators: name: The IceCube Collaboration
Publisher: name: arXiv
Year: 2011
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Experiment (hep-ex)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: The IceCube neutrino observatory in operation at the South Pole, Antarctica, comprises three distinct components: a large buried array for ultrahigh energy neutrino detection, a surface air shower array, and a new buried component called DeepCore. DeepCore was designed to lower the IceCube neutrino energy threshold by over an order of magnitude, to energies as low as about 10 GeV. DeepCore is situated primarily 2100 m below the surface of the icecap at the South Pole, at the bottom center of the existing IceCube array, and began taking physics data in May 2010. Its location takes advantage of the exceptionally clear ice at those depths and allows it to use the surrounding IceCube detector as a highly efficient active veto against the principal background of downward-going muons produced in cosmic-ray air showers. DeepCore has a module density roughly five times higher than that of the standard IceCube array, and uses photomultiplier tubes with a new photocathode featuring a quantum efficiency about 35% higher than standard IceCube PMTs. Taken together, these features of DeepCore will increase IceCube's sensitivity to neutrinos from WIMP dark matter annihilations, atmospheric neutrino oscillations, galactic supernova neutrinos, and point sources of neutrinos in the northern and southern skies. In this paper we describe the design and initial performance of DeepCore.
description: 22 pages, 13 figures
Marumba quercus Denis & Schiffermülle 1775
Creators: name: Wieser, Christian
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Lepidoptera
Sphingidae
Marumba
Marumba quercus

description: Marumba quercus ([Denis & Schiffermüller], 1775)
Von Familie Vilgut aus Villach wurde der Autor aufmerksam gemacht, dass in der Kronen Zeitung vom 11.8.2018 das Bild eines Eichenschwärmers, aufgenommen von Herrn Franz Sattmann, auf der Auslagenscheibe des Gasthofs Felsenkeller in der Schleppe-Kurve in Klagenfurt veröffentlicht wurde. Über Vermittlung von Frau Babka konnte der Fotoautor verifiziert und auch der Fotostandort besichtigt werden. Die Besonderheit dabei ist, dass der Eichenschwärmer (Marumba quercus) aus Kärnten bisher nicht bekannt war. Es kann allerdings auch nicht ausgeschlossen werden, dass es sich bei dem Exemplar um eine unbeabsichtigte Verschleppung aus dem Süden handelt. Aber in Zeiten der vermehrten Ausbreitung wärmeliebender Arten in Richtung Norden kann auch eine bisher noch nicht verifizierte Population im Raum Klagenfurt nicht mehr ausgeschlossen werden. Weitere Beobachtungen sind für eine Bestätigung einer aktuellen Besiedelung erforderlich. Dieses Beispiel unterstreicht deutlich die Wichtigkeit von Presse und interessierten Beobachtern bei der Erforschung der Änderungen in der Kärntner Tierwelt.
description: Published as part of Wieser, Christian, 2017, Weitere Erstfunde und bemerkenswerte Schmetterlingsnachweise aus Kärnten (Insecta: Lepidoptera), pp. 285-291 in Rudolfinum – Jahrbuch des Landesmuseums für Kärnten 2017 on page 290, DOI: 10.5281/zenodo.5725317
Global solutions of the Landau--Lifshitz--Baryakhtar equation
Creators: name: Soenjaya, Agus L.
name: Tran, Thanh
Publisher: name: arXiv
Year: 2023
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35Q56, 35Q60

description: The Landau--Lifshitz--Baryakhtar (LLBar) equation is a generalisation of the Landau--Lifshitz--Gilbert and the Landau--Lifshitz--Bloch equations which takes into account contributions from nonlocal damping and is valid at moderate temperature below the Curie temperature. Therefore, it is used to explain some discrepancies between the experimental observations and the known theories in various problems on magnonics and magnetic domain-wall dynamics. In this paper, the existence and uniqueness of global weak, strong, and regular solutions to LLBar equation are proven. Hölder continuity of the solution is also discussed.
description: title changed, existence & uniqueness of global weak and strong solutions are shown
Multidimensional Fourier series with quantum circuits
Creators: name: Casas, Berta
name: Cervera-Lierta, Alba
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Quantum machine learning is the field that aims to integrate machine learning with quantum computation. In recent years, the field has emerged as an active research area with the potential to bring new insights to classical machine learning problems. One of the challenges in the field is to explore the expressibility of parametrized quantum circuits and their ability to be universal function approximators, as classical neural networks are. Recent works have shown that with a quantum supervised learning model, we can fit any one-dimensional Fourier series, proving their universality. However, models for multidimensional functions have not been explored in the same level of detail. In this work, we study the expressibility of various types of circuit ansatzes that generate multidimensional Fourier series. We found that, for some ansatzes, the degrees of freedom required for fitting such functions grow faster than the available degrees in the Hilbert space generated by the circuits. For example, single-qudit models have limited power to represent arbitrary multidimensional Fourier series. Despite this, we show that we can enlarge the Hilbert space of the circuit by using more qudits or higher local dimensions to meet the degrees of freedom requirements, thus ensuring the universality of the models.
description: 8 pages, 5 figures + appendices
Finite-temperature and finite-time scaling of the directed polymer free-energy with respect to its geometrical fluctuations
Creators: name: Agoritsas, Elisabeth
name: Bustingorry, Sebastian
name: Lecomte, Vivien
name: Schehr, Gregory
name: Giamarchi, Thierry
Publisher: name: arXiv
Year: 2012
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: We study the fluctuations of the directed polymer in 1+1 dimensions in a Gaussian random environment with a finite correlation length ξ and at finite temperature. We address the correspondence between the geometrical transverse fluctuations of the directed polymer, described by its roughness, and the fluctuations of its free-energy, characterized by its two-point correlator. Analytical arguments are provided in favor of a generic scaling law between those quantities, at finite time, non-vanishing ξ and explicit temperature dependence. Numerical results are in good agreement both for simulations on the discrete directed polymer and on a continuous directed polymer (with short-range correlated disorder). Applications to recent experiments on liquid crystals are discussed.
Drude model and Lifshitz formula
Creators: name: Bordag, M.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Since nearly 10 years, it is known that inserting the permittivity of the Drude model into the Lifshitz formula for free energy causes a violation of the third law of thermodynamics. In this paper we show that the standard Matsubara formulation for free energy contains a contribution that is non-perturbative in the relaxation parameter. We argue that the correct formula must have a perturbative expansion and conclude that the standard Matsubara formulation with the permittivity of the Drude model inserted is not correct. We trace the non-perturbative contribution in the complex frequency plane, where it shows up as a self-intersection or a bifurcation of the integration path.
description: accepted for publication in EPJC
Superconducting diode effect in quasi-one-dimensional systems
Creators: name: de Picoli, Tatiana
name: Blood, Zane
name: Lyanda-Geller, Yuli
name: Väyrynen, Jukka I.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: The recent observations of the superconducting diode effect pose the challenge to fully understand the necessary ingredients for non-reciprocal phenomena in superconductors. In this theoretical work, we focus on the non-reciprocity of the critical current in a quasi-one-dimensional superconductor. We define the critical current as the value of the supercurrent at which the quasiparticle excitation gap closes (depairing). Once the critical current is exceeded, the quasiparticles can exchange energy with the superconducting condensate, giving rise to dissipation. Our minimal model can be microscopically derived as a low-energy limit of a Rashba spin-orbit coupled superconductor in a Zeeman field. Within the proposed model, we explore the nature of the non-reciprocal effects of the critical current both analytically and numerically. Our results quantify how system parameters such as spin-orbit coupling and quantum confinement affect the strength of the superconducting diode effect. Our theory provides a complementary description to Ginzburg-Landau theories of the effect.
description: 7 pages, 2 figures
Memoria, lenguaje poético y horizonte ético en "Mundar" de Juan Gelman
Creators: name: Garcia-San Roman, Gemma
Publisher: name: Graduate Studies
Year: 2013
Subjects: subject: Literature--Modern
subject: Literature--Latin American
subject: Literature--Romance
subject: Contemporary Poetry
subject: Argentine Authors
subject: Literary Criticism
subject: Poetic Memory

description: This study analyzes the poetic language of Juan Gelman´s Mundar (2008). It identifies a fragmentation between the literal and the metaphoric planes, which we refer to as the Aesthetic of interruption. This phenomenon provides coherence across the poems in the book, in which we can distinguish various traces of symbolism, originating in the mysticism of St. Hildegard, whose verses appear in the opening epigraph, to French Simbolisme. Via a dialogue with the diverse traditions in which the symbolic background and critical commentary are situated, the central part of this thesis revolves around memory and oblivion. We question the possibility of a critical memory, defined by Ricoeur as the reconciliation of an image with its imprint. Due to an analogous tension arising out of the metaphorical devices, an opening of language takes places, and the releasing of poetic meaning occurs. It is possible, thus, to reach a horizon of understanding that represents the ethical moment when those comrades killed by the military are acknowledged. Together with this recognition, a sociological context also takes shape out of the poems and is manifested as a critical stance against the discourses of “post-memory.”
A diffeomorphism invariant family of metric-affine actions for loop cosmologies
Creators: name: Delhom, Adrià
name: Olmo, Gonzalo J.
name: Singh, Parampreet
Publisher: name: arXiv
Year: 2023
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In loop quantum cosmology (LQC) the big bang singularity is generically resolved by a big bounce. This feature holds even when modified quantization prescriptions of the Hamiltonian constraint are used such as in mLQC-I and mLQC-II. While the later describes an effective description qualitatively similar to that of standard LQC, the former describes an asymmetric evolution with an emergent Planckian de-Sitter pre-bounce phase even in the absence of a potential. We consider the potential relation of these canonically quantized non-singular models with effective actions based on a geometric description. We find a 3-parameter family of metric-affine $f(\mathcal{R})$ theories which accurately approximate the effective dynamics of LQC and mLQC-II in all regimes and mLQC-I in the post-bounce phase. Two of the parameters are fixed by enforcing equivalence at the bounce, and the background evolution of the relevant observables can be fitted with only one free parameter. It is seen that the non-perturbative effects of these loop cosmologies are universally encoded by a logarithmic correction that only depends on the bounce curvature of the model. In addition, we find that the best fit value of the free parameter can be very approximately written in terms of fundamental parameters of the underlying quantum description for the three models. The values of the best fits can be written in terms of the bounce density in a simple manner, and the values for each model are related to one another by a proportionality relation involving only the Barbero-Immirzi parameter.
description: 19 pages, 4 figures and 3 tables
Improved Downward Wavefield with Applications to Reverse Time Migration
Creators: name: Alnabulsi, Salam
Publisher: name: Graduate Studies
Year: 2016
Subjects: subject: Education--Mathematics
subject: Geophysics
subject: FOS: Earth and related environmental sciences
subject: Mathematics
subject: FOS: Mathematics
subject: RTM
subject: Wave equation
subject: Migration
subject: FDM
subject: FEM

description: In this research, we introduce a new technique for wave propagation which produces a lesser amount of reflections in the resulting wavefield. Using these wave-fields in the Reverse Time Migration scheme aims to decrease the negative effect of the multiples that occur in the imaging process. Based on the technique stemming from the absorbing boundary conditions, we implement these conditions inside the domain to generate a forward wavefield while minimizing reflections when going through horizontal interfaces. We test two types of velocity models: elastic and viscoelastic. The benefit of using the viscoelastic model is that it takes into account the attenuation incurred by fluid fill in porous media and, hence, model the effect of amplitude reduction in the imaging process. The finite difference method was used to generate the compressional wavefield in the elastic model, while the finite element method was used for the viscoelastic model. The images were generated using the cross-correlation and the normalized imaging conditions. Finally, we test the approximated velocity models in order to mimic real-field applications. The application of reverse time migration, under this new technique not only detects interface locations, but also creates structural images, and it can identify different types of the saturated fluid in porous media.
Assessing the source of error in the Thomas-Fermi-von Weizsäcker density functional
Creators: name: Thapa, Bishal
name: Jing, Xin
name: Pask, John E.
name: Suryanarayana, Phanish
name: Mazin, Igor I.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: We investigate the source of error in the Thomas-Fermi-von Weizsäcker (TFW) density functional relative to Kohn-Sham density functional theory (DFT). In particular, through numerical studies on a range of materials, for a variety of crystal structures subject to strain and atomic displacements, we find that while the ground state electron density in TFW orbital-free DFT is close to the Kohn-Sham density, the corresponding energy deviates significantly from the Kohn-Sham value. We show that these differences are a consequence of the poor representation of the linear response within the TFW approximation for the electronic kinetic energy, confirming conjectures in the literature. In so doing, we find that the energy computed from a non-self-consistent Kohn-Sham calculation using the TFW electronic ground state density is in very good agreement with that obtained from the fully self-consistent Kohn-Sham solution.
description: 5 pages, 1 figure, 1 table
Matrix-Product based Projected Wave Functions Ansatz for Quantum Many-Body Ground States
Creators: name: Chou, Chung-Pin
name: Pollmann, Frank
name: Lee, Ting-Kuo
Publisher: name: arXiv
Year: 2012
Subjects: subject: Computational Physics (physics.comp-ph)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We develop a new projected wave function approach which is based on projection operators in the form of matrix-product operators (MPOs). Our approach allows to variationally improve the short range entanglement of a given trial wave function by optimizing the matrix elements of the MPOs while the long range entanglement is contained in the initial guess of the wave function. The optimization is performed using standard variational Monte Carlo techniques. We demonstrate the efficiency of our approach by considering a one-dimension model of interacting spinless fermions. In addition, we indicate how to generalize this approach to higher dimensions using projection operators which are based on tensor products.
description: 5 pages, 3 figures
The politics of protection : conceptualizing climatic displacement and a global protection regime
Creators: name: Aageson-Morlock, Megan
Publisher: name: University of British Columbia
Year: 2010

description: Climate change is anticipated to drive millions of people from their homes this century. Estimates indicate that between 200 and 250 million people may be displaced because of rising sea levels, desertification, and increased storm surges working in concert. At present, however, there is no protection regime, institutional mandate, or legal architecture capable of responding to the plight of climatically displaced persons (CDPs). Since 2007, a number of legal regimes have been proposed to provide CDPs with legal assistance. Each regime creates compulsory mandates for states in terms of their assistance to the climatically displaced. Though proposed regimes address the existing legal gaps in protection, they fail to address why states would in fact be willing politically to sign such a treaty. This paper argues that a hard legal framework for CDP protection is not politically prudent. Rather, CDP protection should be pursued through soft legalization. In particular, this paper examines the 1998 Guiding Principles on Internal Displacement and the ways in which their non-binding nature provide a normative framework for the development of a CDP protection instrument. The 1998 Guiding Principles developed in response to the political limitations of the 1951 Refugee Convention and its contemporary application. States have taken increased measures to limit their existing asylum obligations under the legally binding 1951 framework and the non-binding IDP Guiding Principles emerged in direct response to this political resistance. The non-binding nature of the Guiding Principles has not undermined their authoritative force, however, but rather it has served as a powerful tool for protecting vulnerable populations. Thus, this paper contributes to the literature on climatic displacement by conceptualizing how the evolution and application of contemporary protection regimes, as well as their normative frameworks, can shape efforts to protect those who are displaced by climate change.
Nonsingular black holes from conformal symmetries
Creators: name: Cadoni, Mariano
name: Sanna, Andrea Pierfrancesco
Publisher: name: arXiv
Year: 2023
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We derive the form of the metric for static, nonsingular black holes with a de Sitter core, representing a deformation of the Schwarzschild solution, by assuming that the gravitational sources describe a flow between two conformal points, at small and great distances. The resulting black-hole metric turns out to be a particular case of the Fan $\&$ Wang metric, whose parameters have been recently constrained by using the data of the S$2$ star orbits around the galactic centre SgrA$^\ast$.
description: 6 pages, no figures, some discussions improved, matches the version accepted for pubblication in CQG
Perturbative analysis of the Wess-Zumino flow
Creators: name: Kadoh, Daisuke
name: Kikuchi, Kengo
name: Ukita, Naoya
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We investigate an interacting supersymmetric gradient flow in the Wess-Zumino model. Thanks to the nonrenormalization theorem and an appropriate initial condition, we find that any correlator of flowed fields is ultraviolet finite. This is shown at all orders of the perturbation theory using the power counting theorem for one-particle irreducible supergraphs. Since the model does not have the gauge symmetry, the mechanism of realizing the ultraviolet finiteness is quite different from that of the Yang-Mills flow, and this could provide further understanding of the gradient flow approach.
description: 31 pages, 2 figures, v2: published version
An LED pulser for measuring photomultiplier linearity
Creators: name: Friend, M.
name: Franklin, G. B.
name: Quinn, B.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: A light-emitting diode (LED) pulser for testing the low-rate response of a photomultiplier tube (PMT) to scintillator-like pulses has been designed, developed, and implemented. This pulser is intended to simulate 80 ns full width at half maximum photon pulses over the dynamic range of the PMT, in order to precisely determine PMT linearity. This particular design has the advantage that, unlike many LED test rigs, it does not require the use of multiple calibrated LEDs, making it insensitive to LED gain drifts. Instead, a finite-difference measurement is made using two LEDs which need not be calibrated with respect to one another. These measurements give a better than 1% mapping of the response function, allowing for the testing and development of particularly linear PMT bases.
description: 5 pages, 5 figures
The Adoption of Automatic Milking Systems on Canadian Dairy Farms: Changes in Cow Health, Management and Animal Welfare
Creators: name: Tse, Christina
Publisher: name: Graduate Studies
Year: 2016
Subjects: subject: Food Science and Technology
subject: Veterinary Science
subject: robotic milking
subject: Transition
subject: cow health
subject: Management
subject: milk quality
subject: milk production
subject: precision dairy farming
subject: animal welfare

description: Producers with automatic milking systems (AMS) were surveyed to explore the impacts of AMS on their cows and to determine how producers experienced the transition. Producers perceived their transitions to AMS as successful and would recommend it. Cleaning and feeding practices stayed the same. Farms increased herd size, but decreased the number of employees and time devoted to milking labour management. There was little perceived effect on milk quality and cow health. Producers changed health management practices, but majority found health detection easier. Only 20% of producers referred to the Dairy Code of Practice when making plans to adopt AMS. Participation in Dairy Herd Improvement programs decreased. It took on average 7 d to train a cow/heifer to use AMS and 30 d for an entire herd to adapt. Despite some challenges, producers reported that AMS improved profitability, quality of their lives and their cows’ lives, and had met expectations.
GRIDS-Net: Inverse shape design and identification of scatterers via geometric regularization and physics-embedded deep learning
Creators: name: Nair, Siddharth
name: Walsh, Timothy F.
name: Pickrell, Greg
name: Semperlotti, Fabio
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: This study presents a deep learning based methodology for both remote sensing and design of acoustic scatterers. The ability to determine the shape of a scatterer, either in the context of material design or sensing, plays a critical role in many practical engineering problems. This class of inverse problems is extremely challenging due to their high-dimensional, nonlinear, and ill-posed nature. To overcome these technical hurdles, we introduce a geometric regularization approach for deep neural networks (DNN) based on non-uniform rational B-splines (NURBS) and capable of predicting complex 2D scatterer geometries in a parsimonious dimensional representation. Then, this geometric regularization is combined with physics-embedded learning and integrated within a robust convolutional autoencoder (CAE) architecture to accurately predict the shape of 2D scatterers in the context of identification and inverse design problems. An extensive numerical study is presented in order to showcase the remarkable ability of this approach to handle complex scatterer geometries while generating physically-consistent acoustic fields. The study also assesses and contrasts the role played by the (weakly) embedded physics in the convergence of the DNN predictions to a physically consistent inverse design.
description: 23 pages of main text, 10 figures
Organic matter distribution and origin in marine surface sediments on the Canadian Beaufort Sea Shelf
Creators: name: Schwarzkopf, Katharina
name: Fritz, Michael
name: Bröder, Lisa
name: Haghipour, Negar
name: O'Regan, Matt
name: Juhls, Bennet
name: Priest, Taylor
name: Lattaud, Julie
name: Whalen, Dustin
name: Matsuoka, Atushi
name: Pellerin, André
name: Bossé-Demers, Thomas
name: Rudbäck, Daniel
name: Rodriquez-Cuicas, Maria-Emilia
name: Overduin, Pier Paul
name: Vonk, Jorien E.
Publisher: name: Zenodo
Year: 2023

description: The continental shelves of the Arctic Ocean are undergoing profound changes because of climate warming. Large amounts of previously freeze-locked carbon and nutrients are released towards the shelves due to increasing river discharge, deeper permafrost thaw and accelerated coastal erosion. Still, their interactions and their effects on carbon turnover and greenhouse gas fluxes between sediment, ocean, and atmosphere are poorly understood. This study aims to investigate the origin and depositional patterns of organic matter in the Canadian Beaufort Sea. To address this, long and short sediment cores were taken in fall 2021 from twenty-five positions along five major transects that spanned the Beaufort Sea Shelf. We discuss the concentration and regional distribution of organic carbon, nitrogen, mercury, and grain size in surface sediments (upper 2 cm). In addition, bulk 14C radiocarbon ages and stable isotope ratios (δ13C and δ15N) are used to help distinguish sources and degradation status of terrigenous organic matter. Preliminary results show that the material is predominantly fine-grained clayey silt, and the bulk surface ages vary between 5500 and 10000 years before present. We found specific spatial distribution patterns of carbon, nitrogen, and mercury, which highlight the influence of bathymetry, currents, and distance to the Mackenzie River delta on transport and degradation mechanisms of organic matter. The Permafrost Carbon in the Beaufort Shelf (PeCaBeau) project took place on the Research Vessel CCGS Amundsen in September and October 2021 on the Canadian Beaufort Sea Shelf. This project was funded by the EU Horizon 2020 Arctic Research Icebreaker Consortium (ARICE, grant no. 730965).