cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
An Efficient Fokker-Planck Solver and its Application to Stochastic Particle Acceleration in Galaxy Clusters
Creators: name: Donnert, Julius
name: Brunetti, Gianfranco
Publisher: name: arXiv
Year: 2014
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Particle acceleration by turbulence plays a role in many astrophysical environments. The non- linear evolution of the underlying cosmic-ray spectrum is complex and can be described by a Fokker-Planck equation, which in general has to be solved numerically. We present here an implementation to compute the evolution of a cosmic-ray spectrum coupled to turbulence considering isotropic particle pitch-angle distributions and taking into account the relevant particle energy gains and losses. Our code can be used in run time and post-processing to very large astrophysical fluid simulations. We also propose a novel method to compress cosmic- ray spectra by a factor of ten, to ease the memory demand in very large simulations. We show a number of code tests, which firmly establish the correctness of the code. In this paper we focus on relativistic electrons, but our code and methods can be easily extended to the case of hadrons. We apply our pipeline to the relevant problem of particle acceleration in galaxy clusters. We define a sub-grid model for compressible MHD-turbulence in the intra- cluster-medium and calculate the corresponding reacceleration timescale from first principles. We then use a magneto-hydrodynamic simulation of an isolated cluster merger to follow the evolution of relativistic electron spectra and radio emission generated from the system over several Gyrs.
Someday I'll love a body
Creators: name: Snow, Maia
Publisher: name: The University of Texas at Austin
Year: 2020
Subjects: Body
Queer
Art

description: My work is about the abandoned/absent figure. I make paintings about the soft and hard complexities of queer sexuality, gender and the non-binary body. A soft complexity is an understanding, welcoming or acceptance of the realities these bodies live in and through. Discrimination and hatred against these bodies are the hard complexities. The central subject of my current work is the figure in space, which reflects the body as an entity marked both by sex and as a marker of sex. I’m interested in the acts of natural and unnatural imitation in painting: how to choose when and what is represented from observed, lived nature versus the intentional omission of aspects of the visual world to make images from the invented and imagined self. I use plain figure depiction along with color relationships of non-objective painting to create a restrained visual language. The absence of a body is a reminder of what can be. I have simplified my surfaces to contrast figurative elements as a way of pointing to bodies that are not present or represented. I do this to encourage viewers to unlearn and reimagine their conception of what a body is or is not.
Environmental Data Archival: Practices and Benefits
Creators: name: Parton, Graham A
Publisher: name: Zenodo
Year: 2011
Subjects: data and information

description: An overview of the reasons why archiving environmental data properly is an important activity and the benefits to both data suppliers and end users. The talk will give examples from the work of the Centre for Environmental Data Archival at the Rutherford Appleton Laboratory which runs both of NERC's British Atmospheric and Earth Observation Data Centres (BADC and NEODC) covering data delivery, archiving, discovery, visualisation and manipulation services at a facility responsible for over 1 Pb of important environmental data.
description: Previously curated at: http://cedadocs.ceda.ac.uk/895/

Event type: workshop.

The publish date on this item was its original published date.

This work was funded by: Natural Environment Research Council.

This item was not refereed before the publication

Main files in this record:
environmental_data_archival_rmetsoc_meeting_20111005.pptx

Item originally deposited with Centre for Environmental Data Analysis (CEDA) document repository by Dr Graham Parton. Transferred to CEDA document repository community on Zenodo on 2022-11-24
A Metric Graph for Which the Number of Possible Endpoints of a Random Walk Grows Minimally
Creators: name: Chernyshev, V. L.
name: Tolchennikov, A. A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mathematical Physics (math-ph)
subject: Combinatorics (math.CO)
subject: Dynamical Systems (math.DS)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 11N45, 37A50, 57M15

description: We prove that metric graph with the minimal growth of the number of possible endpoints of a random walk is the union of several linear paths coming out of the same vertex
Observation of Magnonic Band Gaps in Magnonic Crystals with Nopnreciprocal Dispersion Relation
Creators: name: Mruczkiewicz, M.
name: Pavlov, E. S.
name: Vysotsky, S. L.
name: Krawczyk, M.
name: Filimonov, Yu. A.
name: Nikitov, S. A.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: An effect of metallization of the magnonic crystal surface on the band gaps formation in the spectra of the surface spin wave (SSW) is studied both theoretically and experimentally. The structures under consideration are one-dimensional magnonic crystals based on yttrium iron garnet with an array of etched grooves with metal screen on the top of the corrugated surface and without it. Due to nonreciprocity of propagation of the SSW the shift of band gap to higher frequency and from the border of the Brillouin zone in presence of conducting overlayer was measured in transmission line experiment. Results of numerical calculations and model analysis are in agreement with experimental data and give further insight into origin of the band gap and properties of the nonreciprocal SSW in metallized magnonic crystals. This gives positive answer to the outstanding question about possibility of detection of magnonic band gaps in the spectra of the spin waves with nonreciprocal dispersion in magnonic crystals and creates potential for new applications and improvements of already existing prototype magnonic devices.
Farmer extension facilitators as a pathway for climate smart agriculture: evidence from southern Malawi
Creators: name: Amadu, Festus O.
Publisher: name: Taylor & Francis
Year: 2022
Subjects: subject: Medicine
subject: Marine Biology
subject: Science Policy
subject: 110309 Infectious Diseases
subject: FOS: Health sciences
subject: Plant Biology
subject: FOS: Biological sciences

description: Climate smart agriculture (CSA) is increasingly vital for enhancing agricultural adaptation to extreme weather shocks and sequestering carbon in the face of climate change. However, CSA adoption remains low in sub-Saharan Africa (SSA) and other developing regions due to resource constraints and weak agricultural extension systems, among other factors. To reverse this trend and increase CSA adoption, the use of participatory extension services like farmer extension facilitators (FEFs) are increasingly viewed as a pathway to improving extension services in rural communities in SSA and elsewhere. Yet, rigorous analyses of the impacts of the FEF approach as a pathway for CSA adoption remain limited. Here we estimate the impacts of the FEF approach on CSA adoption in terms of resource intensity of CSA practices promoted by FEFs through a large CSA-related intervention in southern Malawi. We apply recursive bivariate probit regression to primary survey data from a sample of 808 households across five districts in the project area across southern Malawi in 2016, accounting for endogeneity and selection bias in farmer interaction with FEFs and the impact of the FEF approach on CSA adoption. Results show that interaction with FEFs had a positive and statistically-significant impact on CSA adoption; low, medium, and high resource intensity CSA categories increased by 42%, 87%, and 96%, respectively. The results suggest that the FEF approach can significantly enhance CSA adoption and thereby contribute to the achievement of the Sustainable Development Goals, including climate action in Malawi, similar contexts in SSA, and elsewhere. Key Policy InsightsParticipatory extension systems like the FEF approach can improve agricultural extension services in poor communities and thereby enhance CSA adoption in such areas.Smallholder farmer interaction with FEFs can enhance their adoption of resource-intensive CSA practices.Mainstreaming the FEF approach into national adaptation policies and programmes can help scale up CSA adoption in dryland communities.The FEF approach can enhance an achievement of the Sustainable Development Goals, including climate action in dryland developing countries. Participatory extension systems like the FEF approach can improve agricultural extension services in poor communities and thereby enhance CSA adoption in such areas. Smallholder farmer interaction with FEFs can enhance their adoption of resource-intensive CSA practices. Mainstreaming the FEF approach into national adaptation policies and programmes can help scale up CSA adoption in dryland communities. The FEF approach can enhance an achievement of the Sustainable Development Goals, including climate action in dryland developing countries.
Su alcuni limiti fondamentali: tecniche non classiche
Creators: name: Nocera, Mario
name: Raucci, Roberto
name: Taddeo, Luigi
Publisher: name: Universita' degli Studi di Salerno
Year: 2010

description: Si calcola il limite x 0 3 lim x- sinx = 1 → x 6 evidenziando come detto calcolo si possa ricondurre a quello di limiti notevoli senza utilizzare il primo teorema di de l’Hôpital o le classi delle funzioni infinitesime dello stesso ordine. Si prende spunto dal calcolo del limite per riflettere sull'utilizzo, a volte fatto con troppa disinvoltura, della sostituzione degli infiniti e degli infinitesimi. Inoltre si presenta un risultato teorico dal quale discende il suddetto limite e una prova non classica dell’altro limite notevole x lim ln = 0 x x →+∞ .
Polymer polarity as a design parameter for polymer electrolytes
Creators: name: Wheatle, Bill Kristoff Alban
name: 0000-0003-0550-4905
Publisher: name: The University of Texas at Austin
Year: 2020
Subjects: Batteries
Polymer electrolytes
Molecular dynamics

description: Motivated by the need to improve the safety and energy density of lithium-ion batteries, we explore polymer polarity as a design parameter for polymer electrolytes using molecular simulation. We first correlate molecular-level static ionic aggregation with the degree of uncorrelated ionic motion modulated by the host polymer polarity as a potential means to improve ionic transport. Next, we explore the extent to which polymer polarity can be used as a design parameter alone, finding that a competition between ionic aggregation and polymer dynamics limits ionic conduction. We subsequently investigate how polymer polarity influences the correlations between ionic transport and other design parameters, such as host molecular weight and salt concentration. We discover that such correlations exist only above a threshold polymer polarity where ionic aggregation is largely insensitive to these design parameters. We turn to the success of small molecule electrolytes, whose fast ionic transport is mediated by hosts that typically are blends of high mobility and high polarity components. We find that ionic transport can similarly be enhanced when miscible polymer blends with sufficient contrast in polarity serve as the electrolyte host. Finally, we design blend polymer electrolytes whose performance metrics are their mechanical strength and rate of ionic transport using the machine learning technique known as Bayesian optimization. This algorithm identifies a trade off between these performance metrics and identifies the evolution of design parameters, such as host polymer polarities and molecular weights, with increasing emphasis on ionic transport.
Unlocking the full potential of Earth Observation - a presentation of the work of the National Centre for Earth Observation (NCEO)
Creators: name: Parton, Graham A
Publisher: name: Zenodo
Year: 2010
Subjects: data and information
ecology and environment

description: A presentation about unlocking the full potential of Earth Observation
description: Previously curated at: http://cedadocs.ceda.ac.uk/1235/

The publish date on this item was its original published date.

This item was previously associated with content (as an official url) at: http://www.nceo.ac.uk.

This work was funded by: National Centre for Earth Observation (NCEO).

Main files in this record:
rspsoc_slideshow.pdf

Item originally deposited with Centre for Environmental Data Analysis (CEDA) document repository by Miss Hayley Gray. Transferred to CEDA document repository community on Zenodo on 2022-11-24
Where are the vulnerable children? Identification and comparison of clusters of young children with health and developmental vulnerabilities across Queensland
Creators: name: Areed, Wala Draidi
name: Price, Aiden
name: Arnett, Kathryn
name: Mengersen, Kerrie
name: Thompson, Helen
Publisher: name: arXiv
Year: 2022
Subjects: subject: Applications (stat.AP)
subject: FOS: Computer and information sciences

description: This study aimed to better understand the vulnerability of 5 to 6 year old children in their first year of school, based on five health and development domains. Identification of subgroups of children within these domains can lead to more targeted research and policies to reduce these vulnerabilities. The study focused on finding clusters of geographical regions with high and low proportions of vulnerable children in Queensland, Australia. K-means analysis was conducted on data from the Australian Early Development Census and the Australian Bureau of Statistics. The clusters were then compared with respect to their geographic locations and risk factor profiles. The results are made publicly available via an interactive dashboard application in R Shiny
Conservation and comparison of protein interactions across evolution
Creators: name: McWhite, Claire Darnell
name: 0000-0001-7346-3047
Publisher: name: The University of Texas at Austin
Year: 2020
Subjects: Comparative evolution
Proteomics
Protein complexes

description: We share core molecular systems with organisms across the tree of life. Though studying multiple organisms at once, we can find biological signals that rise above experimental noise. Comparative evolutionary analysis is an approach that combines evolutionary and systems biology, in essence, a parallel assay where each organism is a data point. Repeated observation of a feature across multiple organisms increases confidence that the signal reflects biology. However, integrating data from different species adds a layer of complexity to high-throughput analysis. In this dissertation, I will first present a review of the use of comparative evolution in human disease genetics, then a characterization and comparison of different orthology algorithms, and finally the culmination of this work of a high-throughput discovery of stable protein complexes conserved across plants.
Fixing the Reference Frame for PPMXL Proper Motions Using Extragalactic Sources
Creators: name: Grabowski, Kathleen
name: Carlin, Jeffrey L.
name: Newberg, Heidi Jo
name: Beers, Timothy C.
name: Chen, Li
name: Deng, Licai
name: Grillmair, Carl J.
name: Guhathakurta, Puragra
name: Hou, Jinliang
name: Lepine, Sebastien
name: Liu, Chao
name: Liu, Xiaowei
name: Luo, A-Li
name: Smith, Martin C.
name: Yanny, Brian
name: Zhang, Haotong
name: Zheng, Zheng
Publisher: name: arXiv
Year: 2014
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We quantify and correct systematic errors in PPMXL proper motions using extragalactic sources from the first two LAMOST data releases and the Veron-Cetty & Veron Catalog of Quasars. Although the majority of the sources are from the Veron catalog, LAMOST makes important contributions in regions that are not well-sampled by previous catalogs, particularly at low Galactic latitudes and in the south Galactic cap. We show that quasars in PPMXL have measureable and significant proper motions, which reflect the systematic zero-point offsets present in the catalog. We confirm the global proper motion shifts seen by Wu, Ma, & Zhou (2011), and additionally find smaller-scale fluctuations of the QSO-derived corrections to an absolute frame. We average the proper motions of 158,106 extragalactic objects in bins of 3x3 degrees and present a table of proper motion corrections.
description: Accepted for publication in RAA; 12 pages, 6 figures (Fig. 1 at reduced resolution); full table of corrections available in online journal, with arxiv ancillary files (as ASCII table), or by request
QuYBE -- An Algebraic Compiler for Quantum Circuit Compression
Creators: name: Gulania, Sahil
name: He, Zichang
name: Peng, Bo
name: Govind, Niranjan
name: Alexeev, Yuri
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: QuYBE is an open-source algebraic compiler for the compression of quantum circuits. It has been applied for the efficient simulation of the Heisenberg Hamiltonian on quantum computers. Currently, it can simulate the time dynamics of one-dimensional chains. It includes modules to generate the quantum circuits for the above as well as produce the compressed circuits, which are independent of the time step. It utilizes the Yang-Baxter equation (YBE) to perform the compression. QuYBE enables users to seamlessly design, execute, and analyze the time dynamics of the Heisenberg Hamiltonian on quantum computers. QuYBE is the first step toward making the YBE technique available to a broader community of scientists from multiple domains. The QuYBE compiler is available at https://github.com/ZichangHe/QuYBE
Robust Interlayer-Coherent Quantum Hall States in Twisted Bilayer Graphene
Creators: name: Kim, Dohun
name: Kang, Byungmin
name: Choi, Yong-Bin
name: Watanabe, Kenji
name: Taniguchi, Takashi
name: Lee, Gil-Ho
name: Cho, Gil Young
name: Kim, Youngwook
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We introduce a novel two-dimensional electronic system with ultrastrong interlayer interactions, namely twisted bilayer graphene with a large twist angle, as an ideal ground for realizing interlayer-coherent excitonic condensates. In these systems, subnanometer atomic separation between the layers allows significant interlayer interactions, while interlayer electron tunneling is geometrically suppressed due to the large twist angle. By fully exploiting these two features we demonstrate that a sequence of odd-integer quantum Hall states with interlayer coherence appears at the second Landau level (N = 1). Notably the energy gaps for these states are of order 1 K, which is several orders of magnitude greater than those in GaAs. Furthermore, a variety of quantum Hall phase transitions are observed experimentally. All the experimental observations are largely consistent with our phenomenological model calculations. Hence, we establish that a large twist angle system is an excellent platform for high-temperature excitonic condensation.
Dynamically decoupled three-body interactions with applications to interaction-based quantum metrology
Creators: name: Mahmud, K. W.
name: Tiesinga, E.
name: Johnson, P. R.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We propose a stroboscopic method to dynamically decouple the effects of two-body atom-atom interactions for ultracold atoms, and realize a system dominated by elastic three-body interactions. Using this method, we show that it is possible to achieve the optimal scaling behavior predicted for interaction-based quantum metrology with three-body interactions. Specifically, we show that for ultracold atoms quenched in an optical lattice, we can measure the three-body interaction strength with a precision proportional to ${\bar n}^{-5/2}$ using homodyne quadrature interferometry, and ${\bar n}^{-7/4}$ using conventional collapse-and-revival techniques, where ${\bar n}$ is the mean number of atoms per lattice site. Both precision scalings surpass the nonlinear scaling of ${\bar n}^{-3/2}$, the best so far achieved or proposed with a physical system. Our method of achieving a decoupled three-body interacting system may also have applications in the creation of exotic three-body states and phases.
description: 5 pages, 4 figures
Verifying term graph optimizations using Isabelle/HOL
Creators: name: Webb, Brae J.
name: Hayes, Ian J.
name: Utting, Mark
Publisher: name: arXiv
Year: 2022
Subjects: subject: Programming Languages (cs.PL)
subject: Logic in Computer Science (cs.LO)
subject: FOS: Computer and information sciences

description: Our objective is to formally verify the correctness of the hundreds of expression optimization rules used within the GraalVM compiler. When defining the semantics of a programming language, expressions naturally form abstract syntax trees, or, terms. However, in order to facilitate sharing of common subexpressions, modern compilers represent expressions as term graphs. Defining the semantics of term graphs is more complicated than defining the semantics of their equivalent term representations. More significantly, defining optimizations directly on term graphs and proving semantics preservation is considerably more complicated than on the equivalent term representations. On terms, optimizations can be expressed as conditional term rewriting rules, and proofs that the rewrites are semantics preserving are relatively straightforward. In this paper, we explore an approach to using term rewrites to verify term graph transformations of optimizations within the GraalVM compiler. This approach significantly reduces the overall verification effort and allows for simpler encoding of optimization rules.
description: 14 pages, 7 figures, to be published in CPP2023
Weak Values and Modular Variables From a Quantum Phase Space Perspective
Creators: name: Lobo, Augusto C.
name: Aharonov, Yakir
name: Tollaksen, Jeff
name: Berrigan, Elizabeth M.
name: Ribeiro, Clyffe A.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We address two major conceptual developments introduced by Aharonov and collaborators through a \textit{quantum phase space} approach: the concept of \textit{modular variables} devised to explain the phenomena of quantum dynamical non-locality and the \textit{two-state formalism} for Quantum Mechanics which is a retrocausal time-symmetric interpretation of quantum physics which led to the discovery of \textit{weak values.} We propose that a quantum phase space structure underlies these profound physical insights in a unifying manner. For this, we briefly review the Weyl-Wigner and the coherent state formalisms as well as the inherent symplectic structures of quantum projective spaces in order to gain a deeper understanding of the weak value concept. We also review Schwinger's finite quantum kinematics so that we may apply this discrete formalism to understand Aharonov's modular variable concept in a different manner that has been proposed before in the literature. We discuss why we believe that this\ is indeed the correct kinematic framework for the modular variable concept and how this may shine some light on the physical distinction between quantum dynamical non-locality and the kinematic non-locality, generally associated with entangled quantum systems.
description: arXiv admin note: substantial text overlap with arXiv:1212.5340
Empowerment delle donne e well-being dei bambini: un approccio allo sviluppo umano
Creators: name: Canta, Alba Francesca
Publisher: name: Universita' degli Studi di Salerno
Year: 2020
Subjects: Women’s empowerment
Children’s well-being
Capability approach

description: The purpose of this essay is to briefly examine the discriminations against women and the possible relation between women’s empowerment and children’s well-being. The study is based on a different approach, the capability approach, set up by Amartya Sen in 1980 that describe a new way to assessing a country’s wealth: dignity, rights and opportunities to live a life of value. Capabilities, functioning, agency and empowerment are the main pillars of this concept which is proposed as an alternative of a traditional paradigm. Indeed, the latter value people’s life only in terms of owned assets considering them only as an end and never as a mean to reach something else.
Automorphic Lie Algebras with dihedral symmetry
Creators: name: Knibbeler, Vincent
name: Lombardo, Sara
name: Sanders, Jan A
Publisher: name: arXiv
Year: 2014
Subjects: subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: Mathematical Physics (math-ph)
subject: Rings and Algebras (math.RA)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: The concept of Automorphic Lie Algebras arises in the context of reduction groups introduced in the early 1980s in the field of integrable systems. Automorphic Lie Algebras are obtained by imposing a discrete group symmetry on a current algebra of Krichever-Novikov type. Past work shows remarkable uniformity between algebras associated to different reduction groups. For example, if the base Lie algebra is $\mathfrak{sl}_2(\mathbb{C})$ and the poles of the Automorphic Lie Algebra are restricted to an exceptional orbit of the symmetry group, changing the reduction group does not affect the Lie algebra structure. In the present research we fix the reduction group to be the dihedral group and vary the orbit of poles as well as the group action on the base Lie algebra. We find a uniform description of Automorphic Lie Algebras with dihedral symmetry, valid for poles at exceptional and generic orbits.
description: 20 pages, 5 tables, standard LaTeX2e
X-ray emission from the super-Earth host GJ 1214
Creators: name: Lalitha, S.
name: Poppenhaeger, K.
name: Singh, K. P.
name: Czesla, S.
name: Schmitt, J. H. M. M.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Stellar activity can produce large amounts of high-energy radiation, which is absorbed by the planetary atmosphere leading to irradiation-driven mass-loss. We present the detection and an investigation of high-energy emission in a transiting super-Earth host system, GJ 1214, based on an XMM-Newton observation. We derive an X-ray luminosity LX=7.4E25 erg/s and a corresponding activity level of log(LX/Lbol)~ -5.3. Further, we determine a coronal temperature of about -3.5 MK, which is typical for coronal emission of moderately active low-mass stars. We estimate that GJ 1214 b evaporates at a rate of 1.3E10 g/s and has lost a total of ~2-5.6 MEarth.
description: 5 pages, 3 figures, published in APJL
The Logarithmic Super Divergence and Statistical Inference : Asymptotic Properties
Creators: name: Maji, Avijit
name: Ghosh, Abhik
name: Basu, Ayanendranath
Publisher: name: arXiv
Year: 2014
Subjects: subject: Statistics Theory (math.ST)
subject: FOS: Mathematics

description: Statistical inference based on divergence measures have a long history. Recently, Maji, Ghosh and Basu (2014) have introduced a general family of divergences called the logarithmic super divergence (LSD) family. This family acts as a superfamily for both of the logarithmic power divergence (LPD) family (eg. Renyi, 1961) and the logarithmic density power divergence (LDPD)family introduced by Jones et al. (2001). In this paper we describe the asymptotic properties of the inference procedures resulting from this divergence in discrete models. The properties are well supported by real data examples.
description: 26 pages; Pre-print, Under Review
Non-adiabatic Level Crossing in Resonant Neutrino Oscillations
Creators: name: Parke, Stephen J.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: Analytic results are presented for the probability of detecting an electron neutrino after passage through a resonant oscillation region. If the electron neutrino is produced far above the resonance density, this probability is simply given by $\langle \,P_{ν_e} \, \rangle \approx \sin^2 θ_0+ P_\text{x} \cos 2 θ_0$, where $θ_0$ is the vacuum mixing angle. The probability is averaged over the production as well as the detection positions of the neutrino and $P_\text{x} $ is the Landau-Zener transition probability between adiabatic states. Finally, this result is applied to resonance oscillations within the solar interior.
description: Matches version published in journal
Collective memory in leafcutter ants
Creators: name: Marti, Hannah Elizabeth
Publisher: name: The University of Texas at Austin
Year: 2020
Subjects: Collective behavior
Collective intelligence
Selective copying

description: Like individual organisms, collective organisms such as slime molds and social insect colonies, go through different life-history stages. Collective organisms also show cognitive properties, such as decision-making, learning, and memory. Here, I study the earliest phase of collective life in Atta texana leafcutter ants (Chapter 1) and investigate the duration and mechanisms of collective memory of leaf rejection in Atta colombica (Chapter 2 & 3). In Chapter 1, I measured a mortality rate of 83.7% in foundresses from the time of the mating flight to the emergence of the first workers. And, I found high variation in early growth trajectories of colonies in terms of worker number and fungal garden volume. I found two species of entomopathogenic fungi that were likely causes of mortality in Atta texana foundress queens. In Chapter 2, I examined the mechanisms that allow the maintenance and decay of a learned behavior within leafcutter ant colonies. Specifically, I studied the effects of 1) worker-worker interactions, 2) differential information use by certain workers (old, experienced workers vs young, naïve workers), and 3) worker longevity on the maintenance and decay of collective leaf rejection. In Chapter 3, I studied how individual social learning strategies (e.g., ‘who to copy’ and ‘when to copy’) contribute to the maintenance of colony-level memory. To answer this question, I manipulated colony compositions and measured which groups of foragers copied the foraging preferences of their nestmates based on their own age and past experiences, and on the age, past experiences, and task group (i.e., body size) of their nestmates. I found that leafcutter ants use multiple positive feedback mechanisms of information transfer and a state-dependent social learning strategy, to allow leaf rejection behavior to spread through colonies. When these behavioral rules exist in the context of the constant, gradual turnover of individuals, and other age-based differences in behavior, the emerging whole-colony system is both flexible and capable of retaining information.
Fairify: Fairness Verification of Neural Networks
Creators: name: Biswas, Sumon
name: Rajan, Hridesh
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Fairness of machine learning (ML) software has become a major concern in the recent past. Although recent research on testing and improving fairness have demonstrated impact on real-world software, providing fairness guarantee in practice is still lacking. Certification of ML models is challenging because of the complex decision-making process of the models. In this paper, we proposed Fairify, an SMT-based approach to verify individual fairness property in neural network (NN) models. Individual fairness ensures that any two similar individuals get similar treatment irrespective of their protected attributes e.g., race, sex, age. Verifying this fairness property is hard because of the global checking and non-linear computation nodes in NN. We proposed sound approach to make individual fairness verification tractable for the developers. The key idea is that many neurons in the NN always remain inactive when a smaller part of the input domain is considered. So, Fairify leverages whitebox access to the models in production and then apply formal analysis based pruning. Our approach adopts input partitioning and then prunes the NN for each partition to provide fairness certification or counterexample. We leveraged interval arithmetic and activation heuristic of the neurons to perform the pruning as necessary. We evaluated Fairify on 25 real-world neural networks collected from four different sources, and demonstrated the effectiveness, scalability and performance over baseline and closely related work. Fairify is also configurable based on the domain and size of the NN. Our novel formulation of the problem can answer targeted verification queries with relaxations and counterexamples, which have practical implications.
Discretization in decision analysis
Creators: name: Woodruff, Joshua Morgan
name: 0000-0002-2025-6869
Publisher: name: The University of Texas at Austin
Year: 2020
Subjects: Optimization
Decision analysis
Uncertainty
Assessment error

description: The choice of discretizations in Decision Analysis impacts the accuracy of the probabilistic analysis of the potential strategies. This dissertation introduces a novel method for creating discretizations for specific problems. Next, we introduce the distance metric, which is borrowed from stochastic optimization. This metric indicates how well two cumulative distribution functions match each other in terms of shape. Discretizations that better match the shape are more accurate in estimating the value of a cumulative distribution function at any given percentile. We determine under which conditions the distance is higher or lower, and which discretizations to choose. Finally, we show what happens to the accuracy of discretizations when there is assessment error and how this impacts the choice of discretizations.
Automatic Classification of Galaxy Morphology: a rotationally invariant supervised machine learning method based on the UML-dataset
Creators: name: Fang, G. W.
name: Ba, S.
name: Gu, Y. Z.
name: Lin, Z. S.
name: Hou, Y. J.
name: Qin, C. X.
name: Zhou, C. C.
name: Xu, J.
name: Dai, Y.
name: Song, J.
name: Kong, X.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Classification of galaxy morphology is a challenging but meaningful task for the enormous amount of data produced by the next-generation telescope. By introducing the adaptive polar coordinate transformation, we develop a rotationally invariant supervised machine learning (SML) method that ensures consistent classifications when rotating galaxy images, which is always required to be satisfied physically but difficult to achieve algorithmically. The adaptive polar coordinate transformation, compared with the conventional method of data augmentation by including additional rotated images in the training set, is proved to be an effective and efficient method in improving the robustness of the SML methods. In the previous work, we generated a catalog of galaxies with well-classified morphologies via our developed unsupervised machine learning (UML) method. By using this UML-dataset as the training set, we apply the new method to classify galaxies into five categories (unclassifiable, irregulars, late-type disks, early-type disks, and spheroids). In general, the result of our morphological classifications following the sequence from irregulars to spheroids agrees well with the expected trends of other galaxy properties, including Sérsic indices, effective radii, nonparametric statistics, and colors. Thus, we demonstrate that the rotationally invariant SML method, together with the previously developed UML method, completes the entire task of automatic classification of galaxy morphology.
description: 18 pages, 13 figures, To be published in AJ
Image-based searches for pulsar candidates using MWA VCS data
Creators: name: Sett, S.
name: Bhat, N. D. R.
name: Sokolowski, M.
name: Lenc, E.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Pulsars have proven instrumental in exploring a wide variety of physics. Pulsars at low radio frequencies is crucial to further our understanding of spectral properties and emission mechanisms.The Murchison Widefield Array Voltage Capture System (MWA-VCS) has been routinely used to study and discover pulsars at low frequencies, offering the unique opportunity of recording complex voltages ,which can be off-line beamformed or imaged at millisecond time resolution.Devising imaged-based methods for finding pulsar candidates, which can be verified in beamformed data, can accelerate the complete process and lead to more pulsar detections by reducing the number of tied-array beams required, increasing compute resource efficiency.Despite a factor of ~4 loss in sensitivity, searching for pulsar candidates in images from the MWA-VCS, we can explore a larger parameter space, potentially leading to discoveries of pulsars missed by high-frequency surveys such as pulsars obscured in high-time resolution timeseries data by propagation effects.Image-based searches are also essential to probing parts of parameter space inaccessible to traditional beamformed searches with the MWA.In this paper we describe the innovative approach and capability of dual-processing MWA VCS data, i.e. finding pulsar candidates in these images, and verifying by forming tied-array beam.We developed and tested image-based methods of finding pulsar candidates, based on pulsar properties such as spectral index, polarisation and variability.The efficiency of these methodologies has been verified on known pulsars, and the main limitations explained in terms of sensitivity and low-frequency spectral turnover of some pulsars.No candidates were confirmed to be a new pulsar.This new capability will now be applied to multiple observations to accelerate pulsar discoveries with MWA and speed up future searches with the SKA-Low.
description: 12 pages, 9 figures, accepted for publication in Publications of the Astronomical Society of Australia (PASA)
Imaging trespass
Creators: name: Cartterfield, Anika Todd
name: 0000-0003-2043-9785
Publisher: name: The University of Texas at Austin
Year: 2020
Subjects: Sculpture
Trespass
Studio art

description: My sculptures, performances, and photographs investigate issues surrounding landscape and ownership in late-stage capitalism. The investigation functions through acts of trespass -- recontextualizing trespass as an act of refusal -- a method to push against and forge space within systems that oppress, segment, compartmentalize, and monetize in order to control. In this context, trespass is wielded as a tool to remake the whole, a method of claiming and reclaiming land, body, and time -- a mending of the commons. At the same time, each trespass is also an assertion of individual privilege -- an expression of safety and power that imposes an individual perspective onto an other. These concurrent realities create a fundamental paradox -- while each trespass challenges the paradigm of ownership and control, it risks reinforcing the very dynamic it intends to critique. The challenge for me as an artist is to use an awareness of this distortion on the personal level to point to the distortion of the larger system, allowing the simultaneity to become a lens through which both can be witnessed and understood. What follows is a narrative that traces my recent process of making -- from the initial moment of tension/reaction that catalyzes my engagement with a site, to the process of internalizing and contextualizing that critique to understand the limitations of my own perspective, to the ultimate translation into material -- how the context and content is translated back into form and presented to the viewer.
On the evolution of rotating accreting white dwarfs and type Ia supernovae
Creators: name: Wang, Bo
name: Justham, Stephen
name: Liu, Zhengwei
name: Zhang, Jujia
name: Liu, Dongdong
name: Han, Zhanwen
Publisher: name: arXiv
Year: 2014
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The potential importance of the angular momentum which is gained by accreting white dwarfs (WDs) has been increasingly recognized in the context of type Ia supernova (SN Ia) single-degenerate model. The expectation that the spin of the WD can delay the explosion should help the single-degenerate model to be consistent with the observed properties of most SNe Ia, in particular by avoiding hydrogen contamination. In this article, we attempt to study the most prominent single-degenerate supersoft (WD + MS) channel when the rotation of accreting WDs is considered. We present a detailed binary population synthesis study to examine the predicted population of SNe Ia for this channel. For our standard model, we find that 77% of these SNe Ia explode with WD masses which are low enough to be supported by solid-body rotation (1.378-1.5Msun); this is a substantially higher proportion than found by previous work. Only 2% have WD explosion masses >2.0Msun; these require the initial WD mass to be larger than 1.0 Msun. We further discuss the possible origin of the diversity of SNe Ia from the pre- and post- accretion properties of the WDs in this population. We also suggest that some SN Ia progenitors with substantial circumstellar hydrogen, including some apparent type IIn SNe, might be related to WDs which required support from differential rotation to avoid explosion, since these can still be accreting from hydrogen-rich donors with a relatively high mass-transfer rate at the time of the SN explosion.
description: 22 pages, 15 figures, accepted for publication in MNRAS
Phase structure of 3D Z(N) lattice gauge theories at finite temperature: large-N and continuum limits
Creators: name: Borisenko, Oleg
name: Chelnokov, Volodymyr
name: Gravina, Mario
name: Papa, Alessandro
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We study numerically three-dimensional Z(N) lattice gauge theories at finite temperature, for N = 5, 6, 8, 12, 13 and 20 on lattices with temporal extension $N_t$ = 2, 4, 8. For each model, we locate phase transition points and determine critical indices. We propose also the scaling of critical points with N. The data obtained enable us to verify the scaling near the continuum limit for the Z(N) models at finite temperatures.
description: 17 pages, 2 figures, 9 tables
Fast Outflowing Warm Absorbers in Narrow-Line Seyfert 1 Galaxy PG 1001+054 Revealed by HST/COS Spectra
Creators: name: Fu, Xiao-Dan
name: Wang, Junfeng
name: Xu, Xiaoyu
name: Zhang, Zhi-Xiang
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Narrow-Line Seyfert 1 (NLS1) Galaxies are an important type of active galactic nucleus (AGN), generally expected to be accreting at high Eddington rate. The properties of their outflows and importance of AGN feedback remain intriguing. We report on the discovery of fast outflowing warm absorbers (WAs) in the NLS1 PG 1001+054, with velocities in the range of 7000 to 9000 kilometers per second. They are identified with blueshifted Lyman alpha, N v and Si iv lines in the high resolution ultraviolet (UV) spectra taken with the Cosmic Origins Spectrograph (COS) onboard the Hubble Space Telescope (HST). We perform photoionization modeling using XSTAR with three WAs. The derived physical properties are typical of WAs in terms of ionization and column density, whereas the outflow velocities are significantly higher. The estimated location of these WAs ranges from 1 to 73 parsecs away from the AGN. Together with previous detection of high ionization absorber in the X-ray for PG 1001+054, we suggest that the fast outflowing UV absorber is probably a part of a multiphase outflow. Such structure is likely produced by the outflow launched from AGN at accretion disk scale, which shocks the ambient ISM producing stratified absorbers. Assuming contribution from the three WAs at tens of parsecs, the estimated ratio between the kinetic power of the outflow and AGN Eddington luminosity could reach 1.7 percent, raising the possibility of sufficient influence on the host galaxy when compared to some theoretical models for efficient AGN feedback.
description: 15 pages, 6 figures, 5 tables. Accepted for publication in ApJ
CREB manipulations alter the properties and stability of hippocampal place cells
Creators: name: Davis, Matthew James
name: 0000-0001-9147-3353
Publisher: name: The University of Texas at Austin
Year: 2020
Subjects: Hippocampus
Place cells
CREB
Calcium imaging

description: Location specific firing of hippocampal place cells support spatial learning and memory. Place cell maps can be both stable and flexible across repeated exposures to a familiar environment. The degree of stability is impacted by the specific task demands (e.g. presence of a motivating goal location), changing environmental cues, or simply time. Changes in place cell maps are mediated by various plasticity mechanisms. CREB is an activity dependent transcription factor that has an large role in long-term memory and synaptic & intrinsic plasticity, yet its role in place cell map stability has been understudied. Previous findings indicate that CREB activity has a bidirectional effect on learning and cell excitability. We hypothesized that overexpression of CREB in hippocampal area CA1 would increase learning rates, sharpen place cell tuning, and stabilize place cell maps. On the other hand, we predicted that expression of a CREB repressor, dominant-negative CREB (dn-CREB), would decrease learning, broaden place cell tuning, and destabilize place cell maps. To address these hypotheses, we used longitudinal two-photon calcium imaging to monitor the same cell populations in the CA1 of control, CREB, and dn-CREB mice performing a goal-oriented spatial learning task. Surprisingly, we found that overexpression of CREB reduced the fraction of place cells, while dn-CREB sharpened the tuning of place cells. Both CREB and dn-CREB expression resulted in place cell maps that were hyperstable in response to a change in reward location and slowed the initial reconfiguration of place cells towards the reward location. CREB expression reduced cell firing rates and dn-CREB increased neuronal firing These findings demonstrate that CREB levels and task features work in concert to modulate the properties and map stability of CA1 place cells.