cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Computer-aided Diagnosis of Plus Disease via Quantitative Analysis of the Vascular Architecture in Retinal Fundus Images of Preterm Infants
Creators: name: Oloumi, Faraz
Publisher: name: Graduate Studies
Year: 2015
Subjects: subject: Engineering--Biomedical
subject: retinal vessels, quantitative analysis, fundus image, vessel detection, Gabor filters, thickness, tortuosity, retinopathy of prematurity, plus disease, computer-aided diagnosis, image processing, feature extraction

description: Retinopathy of prematurity (ROP) is a disorder of the eye that may develop in preterm-born infants. If left untreated, ROP may lead to retinal detachment and ultimately blindness. A warrant for treatment of ROP is the detection of plus disease, which is clinically diagnosed by the presence of certain levels of increase in the tortuosity and thickness of retinal vessels. The openness of the major temporal arcade (MTA), the thickest branch of the venules, has also been observed to decrease in the presence of plus disease. It has been shown that there is interexpert disagreement on diagnosis of plus disease, even among expert ophthalmologists and retinal specialists, which calls for development of image processing techniques to detect and diagnose plus disease more accurately by analysis of retinal fundus images of preterm infants. This work presents image processing methods for the extraction of diagnostic features from retinal fundus images of preterm infants, for the purpose of computer-aided diagnosis (CAD) of plus disease. The features include measures of the thickness and openness of the MTA as well as tortuosity of retinal vessels. The methods include directionally sensitive Gabor filters for the detection and extraction of vessels, as well as morphological techniques for segmentation, binarization, and skeletonization of the vasculature. Methods are proposed for tracking and segmentation of only the MTA. Using geometrical modeling and analysis, the openness and thickness of the MTA are quantified. Tortuosity of vessels is quantified by analyzing the variation in the dominant orientation of vessels obtained by the application of Gabor filters. Receiver operating characteristic (ROC) analysis of the diagnostic performance of the measures of thickness, openness, and tortuosity resulted in area under the ROC curves of 0.75, 0.70, and 0.98, respectively. The methods may be used in a clinical or teleophthalmological setting for CAD of plus disease.
Successive Refinement with Decoder Cooperation and its Channel Coding Duals
Creators: name: Asnani, Himanshu
name: Permuter, Haim
name: Weissman, Tsachy
Publisher: name: arXiv
Year: 2012
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: We study cooperation in multi terminal source coding models involving successive refinement. Specifically, we study the case of a single encoder and two decoders, where the encoder provides a common description to both the decoders and a private description to only one of the decoders. The decoders cooperate via cribbing, i.e., the decoder with access only to the common description is allowed to observe, in addition, a deterministic function of the reconstruction symbols produced by the other. We characterize the fundamental performance limits in the respective settings of non-causal, strictly-causal and causal cribbing. We use a new coding scheme, referred to as Forward Encoding and Block Markov Decoding, which is a variant of one recently used by Cuff and Zhao for coordination via implicit communication. Finally, we use the insight gained to introduce and solve some dual channel coding scenarios involving Multiple Access Channels with cribbing.
description: 55 pages, 15 figures, 8 tables, submitted to IEEE Transactions on Information Theory. A shorter version submitted to ISIT 2012
title: Forschen und Lehren in einer digital geprägten Welt : Digitale Didaktik im Darmstädter Modell der Digital Humanities
Creators: name: Rapp, Andrea
Publisher: name: UNSPECIFIED
Year: 2020

description: Die Forderungen nach einer flächendeckenden Entwicklung digitaler Kompetenzen sind angesichts einer zunehmend digital verfassten Wissens- und Informationsgesellschaft berechtigt und von entscheidender Bedeutung für ihre Zukunftsfähigkeit. Erst auf der Basis notwendiger Forschungen zu grundlegenden und erweiterten digitalen Kompetenzen bzw. digitaler Bildung können Konzepte zu ihrer Verortung und Vermittlung entwickelt und implementiert werden. Diese Forderungen gelten nicht allein für die Forschung, sondern insbesondere für die Lehre. Hierzu gehört die Frage nach der Domänengebundenheit digitaler Kompetenzen ebenso wie die nach dem Ort der Vermittlung: Neben einer entsprechend ausgerichteten Fort- und Weiterbildung (Kontext life long learning) müssen bestimmte Grundlagen in der schulischen und universitären (Aus)Bildung gelegt werden. Es gilt, die Reichweite einer fachspezifischen Didaktik auszuloten, und zu definieren, welche Ansätze fachspezifisch, welche übertragbar und welche verallgemeinerbar sind. Damit wird ebenfalls die Frage nach der Digital Literacy als vierter Kulturtechnik sowie nach der Abgrenzung zwischen analoger und digitaler Bildung gestellt. Der Beitrag beschreibt, wie im Bereich der universitären Curricula der Geisteswissenschaften Digitalität reflektiert und vermittelt werden kann. Die Betrachtung von Digitalität in fachdidaktischer Entwicklungsperspektive erfolgt konkret am Beispiel der Darmstädter Digital Humanities im Kontext der Ansätze in Deutschland.
Asymptotic Expansions for lambda_d of the Dimer and Monomer-Dimer Problems
Creators: name: Federbush, Paul
Publisher: name: arXiv
Year: 2012
Subjects: subject: Mathematical Physics (math-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: In the past few years we have derived asymptotic expansions for lambda_d of the dimer problem and lambda_d(p) of the monomer-dimer problem. The many expansions so far computed are collected herein. We shine a light on results in two dimensions inspired by the work of M. E. Fisher. Much of the work reported here was joint with Shmuel Friedland.
description: 4 pages
Quantum Hall Effect, Screening and Layer-Polarized Insulating States in Twisted Bilayer Graphene
Creators: name: Sanchez-Yamagishi, Javier D.
name: Taychatanapat, Thiti
name: Watanabe, Kenji
name: Taniguchi, Takashi
name: Yacoby, Amir
name: Jarillo-Herrero, Pablo
Publisher: name: arXiv
Year: 2011
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 investigate electronic transport in dual-gated twisted bilayer graphene. Despite the sub-nanometer proximity between the layers, we identify independent contributions to the magnetoresistance from the graphene Landau level spectrum of each layer. We demonstrate that the filling factor of each layer can be independently controlled via the dual gates, which we use to induce Landau level crossings between the layers. By analyzing the gate dependence of the Landau level crossings, we characterize the finite inter-layer screening and extract the capacitance between the atomically-spaced layers. At zero filling factor, we observe magnetic and displacement field dependent insulating states, which indicate the presence of counter-propagating edge states with inter-layer coupling.
description: 4 pages, 3 figures
title: Spectrum and spectral density estimation by the Discrete Fourier transform (DFT), including a comprehensive list of window functions and some new at-top windows
Creators: name: Heinzel, Gerhard
name: Rüdiger, Albrecht
name: Schilling, Roland
Publisher: name: Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut) / Laser Interferometry and Gravitational Wave Astronomy
Year: 2002
Subjects: Discrete Fourier Transform
Fast Fourier Transformation
Power Spectra and Power Spectral Densities
Window Function
Flat-Top Window

description: This report tries to give a practical overview about the estimation of power spectra/power spectral densities using the DFT/FFT.
        One point that is emphasized is the relationship between estimates of power spectra and power spectral densities which is given by the effective noise bandwidth (ENBW).
        Included is a detailed list of common and useful window functions, among them the often neglected flat-top windows.
        Special highlights are a procedure to test new programs, a table of comprehensive graphs for each window and the introduction of a whole family of new flat-top windows that feature sidelobe suppression levels of up to -248 dB, as compared with -90 dB of the best flat-top windows available until now.
Random number generators for massively parallel simulations on GPU
Creators: name: Manssen, Markus
name: Weigel, Martin
name: Hartmann, Alexander K.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Computational Physics (physics.comp-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: High-performance streams of (pseudo) random numbers are crucial for the efficient implementation for countless stochastic algorithms, most importantly, Monte Carlo simulations and molecular dynamics simulations with stochastic thermostats. A number of implementations of random number generators has been discussed for GPU platforms before and some generators are even included in the CUDA supporting libraries. Nevertheless, not all of these generators are well suited for highly parallel applications where each thread requires its own generator instance. For this specific situation encountered, for instance, in simulations of lattice models, most of the high-quality generators with large states such as Mersenne twister cannot be used efficiently without substantial changes. We provide a broad review of existing CUDA variants of random-number generators and present the CUDA implementation of a new massively parallel high-quality, high-performance generator with a small memory load overhead.
description: to appear in Eur. Phys. J. Spec. Top. issue "Computer simulations on GPU"
Winning the War of Word: U.S. Foreign Policy Subcultures and the Grand Strategy of Primacy
Creators: name: Dykstra, Cameron
Publisher: name: Graduate Studies
Year: 2015
Subjects: subject: Political Science
subject: FOS: Political science

description: The Clinton presidency was the first in 50 years to not have the spectre of the USSR and the Cold War to shape its grand strategic direction. Rather than realpolitik and adversarial relationships, the US would foster a more cooperative world where American power would be used to serve international goals. Contrary to these early expectations, the Clinton administration followed a different path, one that is best described as primacy. This paper seeks to understand why the Clinton administration chose to pursue a grand strategy of primacy following the end of the Cold War. The findings of this paper will challenge the notion that the US simply reverted to this strategy or that it was a response to international pressures. By doing so we will gain greater understanding into how the United States could have pursued such a unique strategic path.
Random Geometry, Quantum Gravity and the Kähler Potential
Creators: name: Ferrari, Frank
name: Klevtsov, Semyon
name: Zelditch, Steve
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We propose a new method to define theories of random geometries, using an explicit and simple map between metrics and large hermitian matrices. We outline some of the many possible applications of the formalism. For example, a background-independent measure on the space of metrics can be easily constructed from first principles. Our framework suggests the relevance of a new gravitational effective action and we show that it occurs when coupling the massive scalar field to two-dimensional gravity. This yields new types of quantum gravity models generalizing the standard Liouville case.
description: 10 pages; v2: typos (including an exponent in eq. 13) corrected
Buoyant Magnetic Loops in a Global Dynamo Simulation of a Young Sun
Creators: name: Nelson, Nicholas J.
name: Brown, Benjamin P.
name: Brun, Allan Sacha
name: Miesch, Mark S.
name: Toomre, Juri
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: The current dynamo paradigm for the Sun and sun-like stars places the generation site for strong toroidal magnetic structures deep in the solar interior. Sunspots and star-spots on sun-like stars are believed to arise when sections of these magnetic structures become buoyantly unstable and rise from the deep interior to the photosphere. Here we present the first 3-D global magnetohydrodynamic (MHD) simulation in which turbulent convection, stratification, and rotation combine to yield a dynamo that self-consistently generates buoyant magnetic loops. We simulate stellar convection and dynamo action in a spherical shell with solar stratification, but rotating three times faster than the current solar rate. Strong wreaths of toroidal magnetic field are realized by dynamo action in the convection zone. By turning to a dynamic Smagorinsky model for subgrid-scale turbulence, we here attain considerably reduced diffusion in our simulation. This permits the regions of strongest magnetic field in these wreaths to rise toward the top of the convection zone via a combination of magnetic buoyancy instabilities and advection by convective giant cells. Such a global simulation yielding buoyant loops represents a significant step forward in combining numerical models of dynamo action and flux emergence.
description: 6 pages, 3 figures, accepted in ApJ Letters
Persian Complex Predicates: Evidence for Verb Movement from Ellipsis and Negation
Creators: name: SHAFIEI ILKHECHY, Nazila
Publisher: name: Graduate Studies
Year: 2016
Subjects: subject: Linguistics
subject: FOS: Languages and literature
subject: Complex Predicates
subject: VP Ellipsis
subject: Negation Scope
subject: Quantifier Scope

description: Persian has two main verb forms, Simplex Predicates and Complex Predicates (CPr). CPrs consist of a Non-Verbal element (NV), which can be a noun, adjective, adverb or proposition, and a Light Verb (LV) (Vahedi-Langarudi 1996). There has been a controversy on the relation and syntactic position of these two elements. Megerdoomian (2001, 2012) believes that these two elements form a constituent and therefore, treats the CPrs as one syntactic unit. On the other hand, Folli, Harley and Karimi (2005) believe that the NV takes the internal argument as its complement and projects its own phrase, which then merges with the LV. In the present thesis, I provide evidence in support for Megerdoomian’s proposal building on two main lines of argumentation from ellipsis in VPs and the scope of negation. These two argumentations lead me to suggest that the NV and the LV project a head, which I name the Complex-Verb (CV).
The Design and Application of a Molecular Profiling Strategy to Identify Polymicrobial Acute Sepsis Infections
Creators: name: Faria Crowder, Monica
Publisher: name: Graduate Studies
Year: 2015
Subjects: subject: Microbiology
subject: FOS: Biological sciences

description: Sepsis is a term used to describe an array of clinical presentations ranging from mild body dysfunction to multiple organ failure. These clinical signs result from a systemic inflammatory response to microbes or microbial products present in sterile sites such as blood. Current clinical diagnostics rely on culture techniques to identify systemic infections. However, culture lacks sensitivity and a positive result is only obtained in 40% of cases thereby limiting our knowledge of sepsis microbiology. This doctoral study described the development of methods for direct detection of bacteria or bacterial products in blood. A method of lysing host cells and a bacterial DNA extraction protocol was developed and evaluated on mock bacterial communities spiked into whole blood. The results indicated that viable bacteria could be recovered down to 10 CFU/ml using this method. Paired-end Illumina sequencing of the 16S rRNA gene also indicated that the bacterial DNA extraction method enabled recovery of bacterial DNA from spiked blood. This method demonstrated improved detection of systemic bacterial infections involving bacteria as well as their products in three cohorts of clinically septic patients. Application of the paired-end Illumina 16S rRNA sequencing to saponin treated blood from intensive care unit (ICU) and emergency department (ED) patients indicated there were bacterial DNA profiles present in whole blood. These patterns were examined alongside the patient’s clinical data and indicated common molecular profiling patterns were associated with the primary source of infection. Polymicrobial DNA was present in the blood samples with the taxonomic profiles suggesting commensal microbiota were implicated in addition to a principal pathogen. Bacterial DNA from Streptococcus and Staphylococcus were abundant in patients that died in the ICU. Overall this study identified common bacterial DNA patterns in the blood of septic patients which were associated with the patients’ primary source of infection, implicated the commensal microbiota in systemic infection and suggested that sepsis infection may not always involve persistent bacterial bloodstream infections. Rather, this study concluded that bacterial products or viable organisms are likely cyclically present and cleared from the bloodstream resulting in a robust inflammatory response.
Forming doublons by a quantum quench
Creators: name: Schecter, Michael
name: Kamenev, Alex
Publisher: name: arXiv
Year: 2012
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: Repulsive interactions between particles on a lattice may lead to bound states, so called doublons. Such states may be created by dynamically tuning the interaction strength, e.g. using a Feshbach resonance, from attraction to repulsion. We study the doublon production efficiency as a function of the tuning rate at which the on-site interaction is varied. An expectation based on the Landau- Zener law suggests that exponentially few doublons are created in the adiabatic limit. Contrary to such an expectation, we found that the number of produced doublons scales as a power law of the tuning rate with the exponent dependent on the dimensionality of the lattice. The physical reason for this anomaly is the effective decoupling of doublons from the two-particle continuum for center of mass momenta close to the corners of the Brillouin zone. The study of doublon production may be a sensitive tool to extract detailed information about the band structure.
description: 5 pages, 3 figures
Topologically protected Landau levels in bilayer graphene in finite electric fields
Creators: name: Kawarabayashi, Tohru
name: Hatsugai, Yasuhiro
name: Aoki, Hideo
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The zero-energy Landau level of bilayer graphene is shown to be anomalously sharp (delta-function like) against bond disorder as long as the disorder is correlated over a few lattice constants.The robustness of the zero-mode anomaly can be attributed to the preserved chiral symmetry. Unexpectedly, even when we apply a finite potential difference (i.e., an electric field) between the top and the bottom layers, the valley-split $n=0$ Landau levels remain anomalously sharp although they are now shifted away from the zero energy, while the $n=1$ Landau levels exhibit the usual behavior.
description: 5 pages, 5 figures
A $t$-structure on the $\infty$-category of mixed graded modules
Creators: name: Pavia, Emanuele
Publisher: name: arXiv
Year: 2022
Subjects: subject: Category Theory (math.CT)
subject: Algebraic Geometry (math.AG)
subject: K-Theory and Homology (math.KT)
subject: FOS: Mathematics

description: In this work, we shall study in a purely model-independent fashion the $\infty$-category of mixed graded modules over a ring of characteristic $0$, and collect some basic results about its main formal properties. Finally, we shall endow such $\infty$-category with a both left and right complete accessible $t$-structure, showing how this identifies the $\infty$-category of mixed graded modules with the left completion of the Beilinson $t$-structure on the \infinity-category of filtered modules. Most of the content of this paper is already available in literature, and it serves mainly as a reference for future work.
description: First chapter of my PhD thesis, 35 pages, comments welcome
Mixed graded structure on Chevalley-Eilenberg functors
Creators: name: Pavia, Emanuele
Publisher: name: arXiv
Year: 2022
Subjects: subject: Algebraic Geometry (math.AG)
subject: Category Theory (math.CT)
subject: K-Theory and Homology (math.KT)
subject: FOS: Mathematics

description: In this paper, we shall provide a purely $\infty$-categorical construction of the mixed graded structure over Chevalley-Eilenberg complexes computing homology and cohomology of Lie algebras defined over a field $\Bbbk$ of characteristic $0$. While this additional piece of structure on Chevalley-Eilenberg complexes is expected, and already described in terms of explicit models given by chain complexes, there is not a completely formal and model independent description of the mixed graded Chevalley-Eilenberg $\infty$-functors in available literature. After constructing in all details the Chevalley-Eilenberg $\infty$-functors and studying their main formal properties, we present some further conjectures on their behavior.
description: Added some more explicit and motivational descriptions of mixed graded complex in the introduction. Second chapter of my PhD thesis, 57 pages, comments welcome
The Role of the ING3 Epigenetic Regulator in Prostate Cancer
Creators: name: Nabbi, Arash
Publisher: name: Graduate Studies
Year: 2017
Subjects: subject: Biology--Cell
subject: Biology--Molecular
subject: Oncology
subject: Prostate Cancer
subject: Epigenetic regulators
subject: Androgen receptor

description: INhibitor of growth (ING) proteins are epigenetic regulators and stoichiometric members of histone acetyltransferase (KAT) or histone deacetylase (KDAC) complexes. By reading the histone mark H3K4me3, they direct their complexes to chromatin to alter gene expression. This thesis focuses on the role of ING3 in prostate cancer biology. Since rigorous characterization of antibodies is a prerequisite to acquire reliable results, we began by characterizing a new mouse monoclonal antibody against ING3. We profiled the expression of ING3 protein in normal human tissues and found that it is highly expressed in bone marrow, suggesting high expression in hematopoietic cell precursors. We also reported that ING3 protein levels are highest in proliferating tissues of the small intestine and epidermis. These data suggest a role for ING3 in promoting cell growth and renewal. In the second part of this study, we investigated the effects of ING3 on the androgen receptor (AR) pathway in prostate cancer (PC). We hypothesized that ING3 by virtue of being an essential member of TIP60 KAT complex, plays a role in post-translational modifications of AR protein and thereby contributes to PC progression. We found that the levels of ING3 and AR are positively correlated in patient samples and cell lines. ING3 potentiates androgen effects, activating expression of androgen responsive genes and AR-regulated reporters. We showed that ING3 interacts with the binding domain of AR and this interaction happens in the cytoplasm in the absence of androgens. ING3 increases AR-TIP60 interaction, promoting AR acetylation and nuclear translocation. The activating role of ING3 is independent of its ability to target the TIP60 complex to H3K4me3, identifying a previously unknown function for ING3. Knockdown of ING3 inhibits PC cell proliferation and migration, establishing ING3 as a positive regulator of growth in PC. Lastly, we asked whether ING3 could serve as a biomarker to distinguish latent versus aggressive PC. ING3 levels are higher in aggressive PC, with high levels of ING3 predicting shorter overall survival. Analysis with other predictive factors shows that including ING3 levels provides more accurate prognosis in PC.
Jaco: An Offline Running Privacy-aware Voice Assistant
Creators: name: Bermuth, Daniel
name: Poeppel, Alexander
name: Reif, Wolfgang
Publisher: name: arXiv
Year: 2022
Subjects: subject: Cryptography and Security (cs.CR)
subject: Computation and Language (cs.CL)
subject: Human-Computer Interaction (cs.HC)
subject: FOS: Computer and information sciences

description: With the recent advance in speech technology, smart voice assistants have been improved and are now used by many people. But often these assistants are running online as a cloud service and are not always known for a good protection of users' privacy. This paper presents the architecture of a novel voice assistant, called Jaco, with the following features: (a) It can run completely offline, even on low resource devices like a RaspberryPi. (b) Through a skill concept it can be easily extended. (c) The architectural focus is on protecting users' privacy, but without restricting capabilities for developers. (d) It supports multiple languages. (e) It is competitive with other voice assistant solutions. In this respect the assistant combines and extends the advantages of other approaches.
Supersymmetry and Beyond Standard Model Higgs searches at ATLAS
Creators: name: Igonkina, Olga
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The searches for supersymmetric and beyond Standard Model Higgs boson with the ATLAS detector are presented. The results are based on integrated luminosity of 35 pb$^{-1}$ to 1.6 fb$^{-1}$ of proton-proton collision data recorded at a centre-of-mass energy of 7 TeV at LHC. No signal is observed in any of the investigated channel and exclusion limits on production cross-sections are given as function of Higgs boson mass and of minimal supersymmetric model parameters.
description: Presented at the 2011 Hadron Collider Physics symposium (HCP-2011), Paris, France, November 14-18 2011, 4 pages, 9 figures
The Story of Section 295-A: A Law and Literature Approach
Creators: name: McLachlan, Erica
Publisher: name: Graduate Studies
Year: 2017
Subjects: subject: Religion
subject: Religion--History of
subject: History
subject: Law
subject: FOS: Law
subject: section 295-A
subject: Indian Penal Code
subject: religious freedom
subject: India
subject: South Asia
subject: Punjab
subject: Censorship
subject: law and literature

description: This thesis examines the historical origins of section 295-A of the Indian Penal Code using analytical methods borrowed from the law and literature movement. The law was enacted in 1927 in response to controversy that erupted over the acquittal of Mahashe Rajpal, who was the publisher of a scurrilous pamphlet entitled Rangila Rasul. The development of this law is traced through the narratives that appeared in various archival documents, including court rulings, newspaper articles and minutes from the Indian Legislative Assembly Debates. The Rangila Rasul affair, and its culmination in the form of section 295-A, illustrates the multifaceted and entangled relationship that exists between law and narrative, and provides a rich historical context for engaging with contemporary debates surrounding subsequent applications of the law.
On the Optimal Control of the Free Boundary Problems for the Second Order Parabolic Equations. I.Well-posedness and Convergence of the Method of Lines
Creators: name: Abdulla, Ugur G.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: We develop a new variational formulation of the inverse Stefan problem, where information on the heat flux on the fixed boundary is missing and must be found along with the temperature and free boundary. We employ optimal control framework, where boundary heat flux and free boundary are components of the control vector, and optimality criteria consists of the minimization of the sum of $L_2$-norm declinations from the available measurement of the temperature flux on the fixed boundary and available information on the phase transition temperature on the free boundary. This approach allows one to tackle situations when the phase transition temperature is not known explicitly, and is available through measurement with possible error. It also allows for the development of iterative numerical methods of least computational cost due to the fact that for every given control vector, the parabolic PDE is solved in a fixed region instead of full free boundary problem. We prove well-posedness in Sobolev spaces framework and convergence of discrete optimal control problems to the original problem both with respect to cost functional and control.
The role of suction boxes on forming section retention and filler migration
Creators: name: Montgomery, James
Publisher: name: University of British Columbia
Year: 2010

description: An apparatus was constructed to observe fibre mat formation under applied vacuum pressure comparable to that experienced in a suction box. The main focus of study was to determine the effects of system parameters on overall retention, filler distribution, and filler migration by analysing samples through weighing, ashing and EDX analysis. It was found that increasing suction pressure slightly decreased the overall retention, although the effect was greater at higher filler loadings. The forming fabric selection was statistically significant in determining the overall retention, and the significance of forming fabric selection grows with increasing filler loading. The most important factor in determining overall retention was the presence of retention aids. Measurement of the instantaneous permeability of the forming fabric and fibre mat during the forming process showed differences in the permeability curves between forming fabrics, particularly during the initial forming process. The permeability variations are correlated with differences in retention. Tests performed under gravity drainage, to provide a correlation between fabric properties and overall retention results, showed that air permeability had the highest correlation. Sheet splitting and ashing hand sheets formed using cationic PCC filler showed that applying a vacuum during the drainage process decreased the average filler content. The filler was preferentially removed from the wire side of the sheet. Similar tests performed with anionic filler showed that filler charge affects the distribution in a hand sheet. Anionic filler also showed little change in distribution when vacuum was applied during forming. Cationic and anionic filler have different retention mechanisms; attachment and filtration, respectively. Applied vacuum was found to affect the filler distribution of particles retained by attachment with the highest changes at the wire side. Applied vacuum was found to have only a small affect on particles retained by filtration. The reason for both is the compaction of the fibre mat, which occurs to the greatest extent at the wire side. The compaction reduces the size of openings in the mat which will further trap large particles retained by filtration but increase the drag on small particles, possibly exceeding the attractive forces responsible for attachment to the pulp fibres.
The existence of Bogomolny decomposition for baby Skyrme models
Creators: name: Stȩpień, Ł. T.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Mathematical Physics (math-ph)
subject: High Energy Physics - Theory (hep-th)
subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: FOS: Physical sciences

description: We derive the Bogomolny decompositions (Bogomolny equations) for: full baby Skyrme model and for its restricted version (so called, pure baby Skyrme model), in (2+0) dimensions, by using so called, concept of strong necessary conditions. It turns out that Bogomolny decomposition can be derived for restricted baby Skyrme model for arbitrary form of the potential term, while for full baby Skyrme model, such derivation is possible only for some class of the potentials.
Neutron EDM in Four Generation Standard Model
Creators: name: Hisano, Junji
name: Hou, Wei-Shu
name: Xu, Fanrong
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: A fourth generation of quarks, if it exist, may provide sufficient CP violation for the baryon asymmetry of the Universe. We estimate the neutron electric dipole moment in the presence of a fourth generation, and find it would be dominated by the strange quark chromoelectric dipole moment, assuming it does not get wiped out by a Peccei-Quinn symmetry. Both the three electroweak loop and the two-loop electroweak/one-loop gluonic contributions are considered. With m_{b'}, m_{t'} at 500 GeV or so that can be covered at the LHC, and with a Jarlskog CPV factor that is consistent with hints of New Physics in b to s transitions, the neutron EDM is found around 10^{-31}e cm, still far below the 10^{-28}e cm reach of the new experiments being planned or under construction.
description: 4 pages; 5 pages, references added, comment added on hyperon EDM, note added on on t' mass and Higgs mass after EPS-HEP 2011
Human Rhinovirus Infection of Airway Epithelial Cells Modulates Airway Smooth Muscle Migration
Creators: name: Shariff, Sami
Publisher: name: Graduate Studies
Year: 2015
Subjects: subject: Biology--Cell
subject: Microbiology
subject: FOS: Biological sciences
subject: Biology--Molecular
subject: Asthma
subject: HRV
subject: Common Cold
subject: chemotaxis
subject: Migration
subject: Airway smooth muscle
subject: Epithelium
subject: Airway Remodeling

description: The traditional paradigm of airway remodeling in asthma has held that remodeling occurs after many years of chronic inflammation. However, studies have confirmed that remodeling changes are observed in children even before the clinical diagnosis of asthma is established. There is now robust evidence to indicate that children with recurrent human rhinovirus (HRV)-induced wheezing episodes are at significantly increased risk of developing subsequent asthma. A feature of airway remodeling is increased airway smooth muscle (ASM) mass with a greater proximity of the ASM to the subepithelial region, and we interrogated the hypothesis that HRV-induced alterations of airway epithelial cell biology might regulate ASM migration. We demonstrated that ASM chemotaxis is GPCR dependent, can be regulated by cAMP and is dependent upon CCL5 release by the epithelium post-HRV infection. These observations substantiate the growing body of evidence that links HRV infections to the subsequent development of asthma.
Distilling Quantum Entanglement via Mode-Matched Filtering
Creators: name: Huang, Yu-Ping
name: Kumar, Prem
Publisher: name: arXiv
Year: 2011
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We propose a new avenue towards distillation of quantum entanglement that is implemented by directly passing the entangled qubits through a mode-matched filter. This approach can be applied to a common class of entanglement impurities appearing in photonic systems where the impurities inherently occupy different spatiotemporal modes than the entangled qubits. As a specific application, we show that our method can be used to significantly purify the telecom-band entanglement generated via the Kerr nonlinearity in single-mode fibers where a substantial amount of Raman-scattering noise is concomitantly produced.
description: 6 pages, 2 figures, to appear in Phys. Rev. A
Charge asymmetry in the differential cross section of high-energy e+e- photoproduction in the field of a heavy atom
Creators: name: Lee, R. N.
name: Milstein, A. I.
name: Strakhovenko, V. M.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: First quasiclassical correction to the differential cross section of high-energy electron-positron photoproduction in the electric field of a heavy atom is obtained with the exact account of the field. This correction is responsible for the charge asymmetry ${\cal A}$ in this process. When the transverse momentum of at least one of the produced particles is much larger than the electron mass $m$, the charge asymmetry can be as large as tens percent. We also estimate the contribution $\tilde{\cal A}$ to the charge asymmetry coming from the Compton-type diagram. For heavy nuclei, this contribution is negligible. For light nuclei, $\tilde{\cal A}$ is noticeable only when the angle between the momenta of electron and positron is of order of $m/ω$ ($ω$ is the photon energy) while the transverse momenta of both particles are much larger than $m$.
description: 19 pages, 7 figures
Constraining ultralight vector dark matter with the Parkes Pulsar Timing Array second data release
Creators: name: Wu, Yu-Mei
name: Chen, Zu-Cheng
name: Huang, Qing-Guo
name: Zhu, Xingjiang
name: Bhat, N. D. Ramesh
name: Feng, Yi
name: Hobbs, George
name: Manchester, Richard N.
name: Russell, Christopher J.
name: Shannon, R. M.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Composed of ultralight bosons, fuzzy dark matter provides an intriguing solution to challenges that the standard cold dark matter model encounters on sub-galactic scales. The ultralight dark matter with mass $m\sim10^{-23} \rm{eV}$ will induce a periodic oscillation in gravitational potentials with a frequency in the nanohertz band, leading to observable effects in the arrival times of radio pulses from pulsars. Unlike scalar dark matter, pulsar timing signals induced by the vector dark matter are dependent on the oscillation direction of the vector fields. In this work, we search for ultralight vector dark matter in the mass range of $[2\times 10^{-24}, 2\times 10^{-22}]{\rm{eV}}$ through its gravitational effect in the Parkes Pulsar Timing Array (PPTA) second data release. Since no statistically significant detection is made, we place $95\%$ upper limits on the local dark matter density as $ρ_{\rm{\tiny{VF}}} \lesssim 5{\rm{GeV/cm^{3}}}$ for $m\lesssim 10^{-23}{\rm{eV}}$. As no preferred direction is found for the vector dark matter, these constraints are comparable to those given by the scalar dark matter search with an earlier 12-year data set of PPTA.
description: 9 pages, 3 figures, 2 tables; accepted for publication as a Letter in Phys. Rev. D
Quantification of Uncertainty in Stereotactic Radiosurgery
Creators: name: Stanley, Julia
Publisher: name: Graduate Studies
Year: 2015
Subjects: subject: Oncology
subject: Physics
subject: Physics--Radiation
subject: Radiosurgery
subject: Physics
subject: Stereotactic

description: Stereotactic radiosurgery is a highly conformal form of radiation therapy that delivers a high dose of radiation in a single treatment. Since stereotactic radiosurgery is commonly used for brain cancer treatment it is critical that the healthy tissue surrounding the tumor receives as little damage as possible This thesis aims to quantify and compare the uncertainty in treatment plan quality in select phases of the treatment process for metastatic brain tumors treated with stereotactic radiosurgery. While uncertainty is unavoidable in radiation therapy, stereotactic radiosurgery treatment requires strict quality assurance measures to minimize its effect. In order to quantify uncertainty, metrics specifically developed for stereotactic radiosurgery were used to evaluate plan quality. Three important steps in the radiosurgery process were investigated. The first step was contouring or tumor delineation in which the effect of inter-observer contouring variation on plan quality was quantified. The second step was treatment planning in which uncertainty in plan quality due to the effect of calculating plans with different treatment planning algorithms was quantified. The third step was treatment delivery in which plan quality variation for a simple model was quantified for geometric misalignments. Overall a high degree of variation was found to be introduced into the process during the contouring phase as this phase is inherently subjective. Plan quality is directly linked to patient outcome and an understanding and quantification of the uncertainty will improve patient treatment.
The Contribution of TP-AGB and RHeB Stars to the Near-IR Luminosity of Local Galaxies: Implications for Stellar Mass Measurements of High Redshift Galaxies
Creators: name: Melbourne, J.
name: Williams, Benjamin F.
name: Dalcanton, Julianne J.
name: Rosenfield, Philip
name: Girardi, Léo
name: Marigo, P.
name: Weisz, D.
name: Dolphin, A.
name: Boyer, Martha L.
name: Olsen, Knut
name: Skillman, E.
name: Seth, Anil C.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Using high spatial resolution HST WFC3 and ACS imaging of resolved stellar populations, we constrain the contribution of thermally-pulsing asymptotic giant branch (TP-AGB) stars and red helium burning (RHeB) stars to the 1.6 um near-infrared (NIR) luminosities of 23 nearby galaxies. The TP-AGB phase contributes as much as 17% of the integrated F160W flux, even when the red giant branch is well populated. The RHeB population contribution can match or even exceed the TP-AGB contribution, providing as much as 21% of the integrated F160W light. The NIR mass-to-light (M/L) ratio should therefore be expected to vary significantly due to fluctuations in the star formation rate over timescales from 25 Myr to several Gyr. We compare our observational results to predictions based on optically derived star formation histories and stellar population synthesis (SPS) models, including models based on the Padova isochrones (used in popular SPS programs). The SPS models generally reproduce the expected numbers of TP-AGB stars in the sample. The same SPS models, however, give a larger discrepancy in the F160W flux contribution from the TP-AGB stars, over-predicting the flux by a weighted mean factor of 2.3 +/-0.8. This larger offset is driven by the prediction of modest numbers of high luminosity TP-AGB stars at young (<300 Myrs) ages. The best-fit SPS models simultaneously tend to under-predict the numbers and fluxes of stars on the RHeB sequence, typically by a factor of 2.0+/-0.6 for galaxies with significant numbers of RHeBs. Coincidentally, over-prediction of the TP-AGB and under-prediction of the RHeBs result in a NIR M/L ratio largely unchanged for a rapid star formation rate. However, the NIR-to-optical flux ratio of galaxies could be significantly smaller than AGB-rich models would predict, an outcome that has been observed in some intermediate redshift post-starburst galaxies. (Abridged)
description: 28 Pages, 12 Figures, 5 Tables, Accepted for Publication in the Astrophysical Journal
Historical light curve and search for previous outbursts of Nova KT Eridani (2009)
Creators: name: Jurdana-Sepic, R.
name: Ribeiro, V. A. R. M.
name: Darnley, M. J.
name: Munari, U.
name: Bode, M. F.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Context. Nova Eridani (2009) caught the eye of the nova community due to its fast decline from maximum, which was initially missed, and its subsequent development in the radio and X-ray wavelengths. This system also exhibits properties similar to those of the much smaller class of recurrent novae; themselves potential progenitors of Type Ia Supernovae. Aims. We aim to determine the nature and physical parameters of the KT Eri progenitor system. Methods. We searched the Harvard College Observatory archive plates for the progenitor of KT Eri to determine the nature of the system, particularly the evolutionary stage of the secondary.We used the data obtained to search for any periodic signal and the derived luminosity to estimate a recurrence timescale. Furthermore, by comparing the colours of the quiescent system on a colour-magnitude diagram we may infer the nature of the secondary star. Results. We identified the progenitor system of KT Eri and measured a quiescent magnitude of < B >= 14.7 \pm 0.4. No previous outburst was found. However, we suggest that if the nova is recurrent it should be on a timescale of centuries. We find a periodicity at quiescence of 737 days which may arise from reflection effects and/or eclipses in the central binary. The periodicity and the quiescence magnitude of the system suggest that the secondary star is evolved and likely in, or ascending, the Red Giant Branch. A second period is evident at 376 days which has a sinusoidal like light curve. Furthermore, the outburst amplitude of ~ 9 magnitudes is inconsistent with those expected for fast classical novae (~ 17 magnitudes) which may lend further support for an evolved secondary. (Abridged)
description: 6 pages, 5 figures, accepted for publication in A&A