cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Metabolomic characterisation of malignant pleural mesothelioma cell lines and tumours
Creators: name: Olanipekun, Michael
Publisher: name: Imperial College London
Year: 2022

description: Malignant pleural mesothelioma (MPM) is a devastating disease caused by asbestos exposure. The pathophysiology and genomic landscape of MPM have been well-researched, but more must be understood to improve disease outcomes. The metabolome of MPM is mostly unexplored and could contain biologically relevant information. The goal of this thesis is to uncover mechanisms of MPM via the metabolomic profiling of patient-derived MPM cell lines and their parent tumours. First, a gas chromatography–mass spectrometry (GC-MS) protocol for rapid, semi-targeted profiling of cellular metabolites from commercially available MPM cell lines was optimised. Second, a wider, untargeted ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS) platform was applied to characterise compounds from primary MPM cell lines, with regards to pathophysiology. Then, cellular metabolites identified were mapped to typical gene copy number variations (CNVs) to identify key interactions. To conclude, the reported metabolomes of primary MPM cell lines and parent tumours were analysed to identify robust mechanisms observable in both cell lines and tumours. Metabolomic analysis of MPM revealed associations between sphingolipid metabolism and biphasic pathology. Additionally, an association between 9p21.3 locus deletion and tryptophan metabolism was observed. Similarly, loss of the neurofibromin-2 (NF2) gene in primary cell lines and tumours resulted in increased long-chain acylcarnitine abundance. These findings, along with the novel analysis pipeline described in this thesis, contribute to the growing body of research aiming to understand and combat MPM.
Informing Geometric Deep Learning with Electronic Interactions to Accelerate Quantum Chemistry
Creators: name: Qiao, Zhuoran
name: Christensen, Anders S.
name: Welborn, Matthew
name: Manby, Frederick R.
name: Anandkumar, Anima
name: Miller, Thomas F.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Machine Learning (cs.LG)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: Predicting electronic energies, densities, and related chemical properties can facilitate the discovery of novel catalysts, medicines, and battery materials. By developing a physics-inspired equivariant neural network, we introduce a method to learn molecular representations based on the electronic interactions among atomic orbitals. Our method, OrbNet-Equi, leverages efficient tight-binding simulations and learned mappings to recover high fidelity quantum chemical properties. OrbNet-Equi models a wide spectrum of target properties with an accuracy consistently better than standard machine learning methods and a speed orders of magnitude greater than density functional theory. Despite only using training samples collected from readily available small-molecule libraries, OrbNet-Equi outperforms traditional methods on comprehensive downstream benchmarks that encompass diverse main-group chemical processes. Our method also describes interactions in challenging charge-transfer complexes and open-shell systems. We anticipate that the strategy presented here will help to expand opportunities for studies in chemistry and materials science, where the acquisition of experimental or reference training data is costly.
The MuPix Telescope: A Thin, high Rate Tracking Telescope
Creators: name: Augustin, H.
name: Berger, N.
name: Dittmeier, S.
name: Grzesik, C.
name: Hammerich, J.
name: Huang, Q.
name: Huth, L.
name: Kiehn, M.
name: Kozlinskiy, A.
name: Meier, F.
name: Perić, I.
name: Perrevoort, A. -K.
name: Schöning, A.
name: Bruch, D. vom
name: Wauters, F.
name: Wiedner, D.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: The MuPix Telescope is a particle tracking telescope, optimized for tracking low momentum particles and high rates. It is based on the novel High-Voltage Monolithic Active Pixel Sensors (HV-MAPS), designed for the Mu3e tracking detector. The telescope represents a first application of the HV-MAPS technology and also serves as test bed of the Mu3e readout chain. The telescope consists of up to eight layers of the newest prototypes, the MuPix7 sensors, which send data self-triggered via fast serial links to FPGAs, where the data is time-ordered and sent to the PC. A particle hit rate of 1 MHz per layer could be processed. Online tracking is performed with a subset of the incoming data. The general concept of the telescope, chip architecture, readout concept and online reconstruction are described. The performance of the sensor and of the telescope during test beam measurements are presented.
description: Proceedings TWEPP 2016, 8 pages, 7 figures
On the consistency of M-estimators in nonlinear dynamic models
Creators: name: Delaitre, Jacques-Henri.
Publisher: name: Monash University
Year: 2022

description: This thesis was scanned from the print manuscript for digital preservation and is copyright the author.
 Researchers can access this thesis by asking their local university, institution or public library to
 make a request on their behalf. Monash staff and postgraduate students can use the link in the References field.
Cross-Correlation Investigation of Anyon Statistics in the $ν=1/3$ and $2/5$ Fractional Quantum Hall States
Creators: name: Glidic, P.
name: Maillet, O.
name: Aassime, A.
name: Piquard, C.
name: Cavanna, A.
name: Gennser, U.
name: Jin, Y.
name: Anthore, A.
name: Pierre, F.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Recent pioneering works have set the stage for exploring anyon braiding statistics from negative current cross-correlations along two intersecting quasiparticle beams. In such a dual-source - analyzer quantum point contact setup, also referred to as 'collider', the anyon exchange phase of fractional quantum Hall quasiparticles is predicted to be imprinted into the cross-correlations characterized by an effective Fano-factor $P$. In the case of symmetric incoming quasiparticle beams, conventional fermions result in a vanishing $P$. In marked contrast, we observe signatures of anyon statistics in the negative $P$ found both for the $e/3$ Laughlin quasiparticles at filling factor $ν=1/3$ ($P\approx-2$, corroborating previous findings), and for the $e/5$ quasiparticles in the hierarchical state $ν=2/5$ ($P\approx-1$). Nevertheless, we argue that the quantitative connection between numerical value of $P\neq0$ and specific fractional exchange phase is hampered by the influence of the analyzer conductance dependence on the voltages used to generate the quasiparticles. Finally, we address the important challenge how to distinguish at $ν=1/3$ between negative cross-correlations induced by a fractional braid phase, and those resulting from a different Andreev-like mechanism. Although with symmetric sources $P$ does not exhibit signatures of a crossover when the analyzer is progressively detuned to favor Andreev processes, we demonstrate that changing the balance between sources provides a mean to discriminate between the two mechanisms.
Exponential smoothing of seasonal time series without seasonal smoothing constant
Creators: name: Shami, Roland G.
Publisher: name: Monash University
Year: 2022

description: This thesis was scanned from the print manuscript for digital preservation and is copyright the author.
 Researchers can access this thesis by asking their local university, institution or public library to
 make a request on their behalf. Monash staff and postgraduate students can use the link in the References field.
Stability and Fourier-series periodic solution in the binary stellar systems
Creators: name: Mia, Rajib
name: Kushvah, Badam Singh
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: In this paper, we use the restricted three body problem in the binary stellar systems, taking photogravitational effects of both the stars. The aim of this study is to investigate the motion of the infinitesimal mass in the vicinity of the Lagrangian points. We have computed semi-analytical expressions for the locations of the collinear points with the help of the perturbation technique. The stability of the triangular points is studied in stellar binary systems Kepler-34, Kepler-35, Kepler-413 and Kepler-16. To investigate the stability of the triangular points, we have obtained the expressions for critical mass which depends on the radiation of both primaries. Fourier-series method is applied to obtain periodic orbits of the infinitesimal mass around triangular points in binary stellar systems. We have obtained Fourier expansions of the periodic orbits around triangular points upto third order terms. A comparison is made between periodic orbits obtained by Fourier-series method and with Runge-Kutta integration of fourth order.
description: Published in the journal Few-Body Systems
V-Edge: Virtual Edge Computing as an Enabler for Novel Microservices and Cooperative Computing
Creators: name: Dressler, Falko
name: Chiasserini, Carla Fabiana
name: Fitzek, Frank H. P.
name: Karl, Holger
name: Cigno, Renato Lo
name: Capone, Antonio
name: Casetti, Claudio
name: Malandrino, Francesco
name: Mancuso, Vincenzo
name: Klingler, Florian
name: Rizzo, Gianluca
Publisher: name: arXiv
Year: 2021
Subjects: subject: Networking and Internet Architecture (cs.NI)
subject: FOS: Computer and information sciences

description: As we move from 5G to 6G, edge computing is one of the concepts that needs revisiting. Its core idea is still intriguing: instead of sending all data and tasks from an end user's device to the cloud, possibly covering thousands of kilometers and introducing delays that are just owed to limited propagation speed, edge servers deployed in close proximity to the user, e.g., at some 5G gNB, serve as proxy for the cloud. Yet this promising idea is hampered by the limited availability of such edge servers. In this paper, we discuss a way forward, namely the virtual edge computing (V-Edge) concept. V-Edge bridges the gap between cloud, edge, and fog by virtualizing all available resources including the end users' devices and making these resources widely available using well-defined interfaces. V-Edge also acts as an enabler for novel microservices as well as cooperative computing solutions. We introduce the general V-Edge architecture and we characterize some of the key research challenges to overcome, in order to enable wide-spread and even more powerful edge services.
Sturmian bases for two-electron systems in hyperspherical coordinates
Creators: name: Abdouraman, A.
name: Frappiccini, Ana Laura
name: Hamido, A.
name: Mota-Furtado, F.
name: O'Mahony, P. F.
name: Mitnik, D.
name: Gasaneo, G.
name: Piraux, B.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We give a detailed account of an $\it{ab}$ $\it{initio}$ spectral approach for the calculation of energy spectra of two active electron atoms in a system of hyperspherical coordinates. In this system of coordinates, the Hamiltonian has the same structure as the one of atomic hydrogen with the Coulomb potential expressed in terms of a hyperradius and the nuclear charge replaced by an angle dependent effective charge. The simplest spectral approach consists in expanding the hyperangular wave function in a basis of hyperspherical harmonics. This expansion however, is known to be very slowly converging. Instead, we introduce new hyperangular sturmian functions. These functions do not have an analytical expression but they treat the first term of the multipole expansion of the electron-electron interaction potential, namely the radial electron correlation, exactly. The properties of these new functions are discussed in detail. For the basis functions of the hyperradius, several choices are possible. In the present case, we use Coulomb sturmian functions of half integer angular momentum. We show that, in the case of H$^-$, the accuracy of the energy and the width of the resonance states obtained through a single diagonalization of the Hamiltonian, is comparable to the values given by state-of-the-art methods while using a much smaller basis set. In addition, we show that precise values of the electric-dipole oscillator strengths for $S\rightarrow P$ transitions in helium are obtained thereby confirming the accuracy of the bound state wave functions generated with the present method.
description: 28 pages, 4 figures
Curved space-times and string theory
Creators: name: Pasarin, Oscar
Publisher: name: Imperial College London
Year: 2022

description: We discuss the feasibility of different kinds of curved space-times as backgrounds for string theory. This thesis is divided into two parts. First, we focus on the double copy procedure and apply it to the Born-Infeld solution in open string theory in the approximation when field-strength derivative terms can be ignored. This process leads us to a generalised version of the Schwarzschild metric which looks non-singular at the origin. Whether this metric is a solution to some closed string equations of motion is also discussed. In the second half of the thesis, Kundt space-times are studied. We show how it is possible to obtain solutions to the Weyl anomaly equations for a background formed by a Kundt metric and a dilaton. The inclusion of a B-field is mentioned but not implemented.
The arbitrage pricing theory : factor analysis, errors-in-variables and structural stability
Creators: name: La, Kacie L.
Publisher: name: Monash University
Year: 2022

description: This thesis was scanned from the print manuscript for digital preservation and is copyright the author.
 Researchers can access this thesis by asking their local university, institution or public library to
 make a request on their behalf. Monash staff and postgraduate students can use the link in the References field.
Gain and phase calibration of sensor arrays from ambient noise by cross-spectral measurements fitting
Creators: name: Vanwynsberghe, Charles
name: Bouley, Simon
name: Antoni, Jérôme
Publisher: name: arXiv
Year: 2022
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: We address the problem of blind gain and phase calibration of a sensor array from ambient noise. The key motivation is to ease the calibration process by avoiding a complex procedure setup. We show that computing the sample covariance matrix in a diffuse field is sufficient to recover the complex gains. To do so, we formulate a non-convex least-square problem based on sample and model covariances. We propose to obtain a solution by low-rank matrix approximation, and two efficient proximal algorithms are derived accordingly. The first one solves the problem modified with a convex relaxation to guarantee that the solution is a global minimizer, and the second one directly solves the initial non-convex problem. We investigate the efficiency of the proposed algorithms by both numerical and experimental results according to different sensing configurations. These show that efficient calibration highly depends on how the measurements are correlated. That is, estimation is achieved more accurately when the field is spatially over-sampled.
description: Accepted in the Journal of the Acoustical Society of America
Materials and methods from Keep numbers in view: red-eared sliders (Trachemys scripta elegans) learn to discriminate relative quantities
Creators: name: Sun, Xiaoqian
name: Piao, Yige
name: Wang, Tongliang
name: Wang, Jichao
name: Fu, Jinzhong
name: Cui, Jianguo
Publisher: name: The Royal Society
Year: 2023
Subjects: classificationCode: 170299
subject: Cognitive Science not elsewhere classified
classificationCode: 60801
subject: Animal Behaviour

description: The detailed experimental materials and methods
Interaction-induced non-Hermitian topological phases from a dynamical gauge field
Creators: name: Faugno, William N
name: Ozawa, Tomoki
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: We present a minimal non-Hermitian model where a topologically nontrivial complex energy spectrum is induced by inter-particle interactions. Our model consists of a one-dimensional chain with a dynamical non-Hermitian gauge field with density dependence. The model is topologically trivial for a single particle system, but exhibits nontrivial non-Hermitian topology with a point gap when two or more particles are present in the system. We construct an effective doublon model to describe the nontrivial topology in the presence of two particles, which quantitatively agrees with the full interacting model. Our model can be realized by modulating hoppings of the Hatano-Nelson model; we provide a concrete Floquet protocol to realize the model in atomic and optical settings.
Numerical relativity higher order gravitational waveforms of eccentric, spinning, non-precessing binary black hole mergers
Creators: name: Joshi, Abhishek V.
name: Rosofsky, Shawn G.
name: Haas, Roland
name: Huerta, E. A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We use the open source, community-driven, numerical relativity software, the Einstein Toolkit to study the physics of eccentric, spinning, nonprecessing binary black hole mergers with mass-ratios $q=\{2, 4, 6\}$, individual dimensionless spin parameters $χ_{1z}=\pm0.6$, $χ_{2z}=\pm0.3$, that include higher order gravitational wave modes $\ell\leq4$, except for memory modes. Assuming stellar mass binary black hole mergers that may be detectable by the advanced LIGO detectors, we find that including modes up to $\ell=4$ increases the signal-to-noise of compact binaries between $3.5\%$ to $35\%$, compared to signals that only include the $\ell=|m|=2$ mode. We use two waveform models, TEOBResumS and SEOBNRE, which incorporate spin and eccentricity corrections in the waveform dynamics, to quantify the orbital eccentricity of our numerical relativity catalog in a gauge-invariant manner through fitting factor calculations. Our findings indicate that the inclusion of higher order wave modes has a measurable effect in the recovery of moderately and highly eccentric black hole mergers, and thus it is essential to develop waveform models and signal processing tools that accurately describe the physics of these astrophysical sources.
description: 13 pages, 5 figures, updated manuscript with added waveform comparisons to TEOBResumS. accepted in Phys. Rev. D
Herschel Observations of Dusty Debris Disks
Creators: name: Vican, Laura
name: Schneider, Adam
name: Bryden, Geoff
name: Melis, Carl
name: Zuckerman, B.
name: Rhee, Joseph
name: Song, Inseok
Publisher: name: arXiv
Year: 2016
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present results from two Herschel observing programs using the Photodetector Array Camera and Spectrometer. During three separate campaigns, we obtained Herschel data for 24 stars at 70, 100, and 160 microns. We chose stars that were already known or suspected to have circumstellar dust based on excess infrared emission previously measured with IRAS or Spitzer, and used Herschel to examine long-wavelength properties of the dust. Fifteen stars were found to be uncontaminated by background sources, and possess infrared emission most likely due to a circumstellar debris disk. We analyzed the properties of these debris disks to better understand the physical mechanisms responsible for dust production and removal. Seven targets were spatially resolved in the Herschel images. Based on fits to their spectral energy distributions, nine disks appear to have two temperature components. Of these nine, in three cases, the warmer dust component is likely the result of a transient process rather than a steady state collisional cascade. The dust belts at four stars are likely stirred by an unseen planet, and merit further investigation.
description: 11 figures, 5 tables, Accepted to ApJ
Machine Learning-Based 3D Channel Modeling for U2V mmWave Communications
Creators: name: Mao, Kai
name: Zhu, Qiuming
name: Song, Maozhong
name: Li, Hanpeng
name: Ning, Benzhe
name: Hua, Boyu
name: Fan, Wei
Publisher: name: arXiv
Year: 2021
Subjects: subject: Signal Processing (eess.SP)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Unmanned aerial vehicle (UAV) millimeter wave (mmWave) technologies can provide flexible link and high data rate for future communication networks. By considering the new features of three-dimensional (3D) scattering space, 3D velocity, 3D antenna array, and especially 3D rotations, a machine learning (ML) integrated UAV-to-Vehicle (U2V) mmWave channel model is proposed. Meanwhile, a ML-based network for channel parameter calculation and generation is developed. The deterministic parameters are calculated based on the simplified geometry information, while the random ones are generated by the back propagation based neural network (BPNN) and generative adversarial network (GAN), where the training data set is obtained from massive ray-tracing (RT) simulations. Moreover, theoretical expressions of channel statistical properties, i.e., power delay profile (PDP), autocorrelation function (ACF), Doppler power spectrum density (DPSD), and cross-correlation function (CCF) are derived and analyzed. Finally, the U2V mmWave channel is generated under a typical urban scenario at 28 GHz. The generated PDP and DPSD show good agreement with RT-based results, which validates the effectiveness of proposed method. Moreover, the impact of 3D rotations, which has rarely been reported in previous works, can be observed in the generated CCF and ACF, which are also consistent with the theoretical and measurement results.
description: IEEE Internet of Things Journal, early access, Mar. 2022
Field-effect transistors of high-mobility few-layer SnSe$_{2}$
Creators: name: Guo, Chenglei
name: Tian, Zhen
name: Xiao, Yanjun
name: Mi, Qixi
name: Xue, Jiamin
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We report the transport properties of mechanically exfoliated few-layer SnSe$_{2}$ flakes, whose mobility is found with four probe measurements to be ~ 85 cm$^{2}$V$^{-1}$s$^{-1}$ at 300 K, higher than those of the majority of few-layer transitional metal dichalcogenides (TMDs). The mobility increases strongly with decreased temperature, indicating a phonon limited transport. The conductivity of the semiconducting SnSe$_{2}$ shows a metallic behavior, which is explained by two competing factors involving the different temperature dependence of mobility and carrier density. The Fermi level is found to be 87 meV below the conduction band minima (CBM) at 300 K and 12 meV below the CBM at 78 K, resulting from a heavy n-type doping. Previous studies have found SnSe$_{2}$ field-effect transistors (FETs) to be very difficult to turn off. We find the limiting factor to be the flake thickness compared with the maximum depletion width. With fully depleted devices, we are able to achieve a current on-off ratio of ~10$^{5}$. These results demonstrate the great potential of SnSe2 as a two dimensional (2D) semiconducting material and are helpful for our understanding of other heavily doped 2D materials.
description: 13 pages, 4 figures
Electronic properties of emergent topological defects in chiral $p$-wave superconductivity
Creators: name: Zhang, L. -F.
name: Becerra, V. Fernández
name: Covaci, L.
name: Milošević, M. V.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Chiral $p$-wave superconductors in applied magnetic field can exhibit more complex topological defects than just conventional superconducting vortices, due to the two-component order parameter (OP) and the broken time-reversal symmetry. We investigate the electronic properties of those exotic states, some of which contain clusters of one-component vortices in chiral components of the OP and/or exhibit skyrmionic character in the \textit{relative} OP space, all obtained as a self-consistent solution of the microscopic Bogoliubov-de Gennes equations. We reveal the link between the local density of states (LDOS) of the novel topological states and the behavior of the chiral domain wall between the OP components, enabling direct identification of those states in scanning tunneling microscopy. For example, a skyrmion always contains a closed chiral domain wall, which is found to be mapped exactly by zero-bias peaks in LDOS. Moreover, the LDOS exhibits electron-hole asymmetry, which is different from the LDOS of conventional vortex states with the same vorticity. Finally, we present the magnetic field and temperature dependence of the properties of a skyrmion, indicating that this topological defect can be surprisingly large in size, and can be pinned by an artificially indented non-superconducting closed path in the sample. These features are expected to facilitate the experimental observation of skyrmionic states, thereby enabling experimental verification of chirality in emerging superconducting materials.
Van Vleck paramagnetism and enhancement of effective moment with magnetic field in rare earth orthovanadate EuVO4
Creators: name: Ranaut, Dheeraj
name: Mukherjee, K.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The 4f^6 systems were hypothesized to possess non-magnetic (J = 0) ground state. However, all such systems have distinctly shown the presence of non-zero effective moment. In this context, a rare earth orthovanadate EuVO4, which in spite of having J = 0 ground state, possess non-zero magnetic moment. Our studies reveal three different regions in this compound, boundaries of which are demarcated from susceptibility data. The high temperature susceptibility exhibits linear dependence on temperature which arises due to tetragonal crystal field, followed by a temperature independent plateau like region, ascribed to Van Vleck paramagnetism. At low temperatures, Curie-Weiss like behaviour is observed, which arise due to magnetic Eu2+ moments and results in non-zero effective moment. Our analysis reveals that the separation (λ) between the J = 0 and J = 1 states decreases on increasing the external magnetic field which leads to an enhanced effective moment at higher fields.
Complex lagrangian submanifolds in holomorphic Symplectic varieties and differential graded algebras
Creators: name: Mladenov, Borislav
Publisher: name: Imperial College London
Year: 2022

description: We present applications of deformation quantisation techniques to holomorphic symplectic geometry. In particular, we calculate certain Ext groups between quantisable Lagrangian D-branes, which count the massless open strings connecting the D-branes, and show the corresponding RHom DG-algebras are formal. Auxiliary results on A-inf modules over graded algebras are presented as well.
Independent Set Reconfiguration Thresholds of Hereditary Graph Classes
Creators: name: de Berg, Mark
name: Jansen, Bart M. P.
name: Mukherjee, Debankur
Publisher: name: arXiv
Year: 2016
Subjects: subject: Discrete Mathematics (cs.DM)
subject: FOS: Computer and information sciences
subject: G.2.1

description: Traditionally, reconfiguration problems ask the question whether a given solution of an optimization problem can be transformed to a target solution in a sequence of small steps that preserve feasibility of the intermediate solutions. In this paper, rather than asking this question from an algorithmic perspective, we analyze the combinatorial structure behind it. We consider the problem of reconfiguring one independent set into another, using two different processes: (1) exchanging exactly $k$ vertices in each step, or (2) removing or adding one vertex in each step while ensuring the intermediate sets contain at most $k$ fewer vertices than the initial solution. We are interested in determining the minimum value of $k$ for which this reconfiguration is possible, and bound these threshold values in terms of several structural graph parameters. For hereditary graph classes we identify structures that cause the reconfiguration threshold to be large.
description: 31 pages, 3 figures, accepted in 36th IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS), 2016
$η_{c}$ Elastic and Transition Form Factors: Contact Interaction and Algebraic Model
Creators: name: Bedolla, Marco A.
name: Raya, Khépani
name: Cobos-Martínez, J. J.
name: Bashir, Adnan
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: For the flavor-singlet heavy quark system of charmonia in the pseudoscalar ($η_c(1S)$) channel, we calculate the elastic (EFF) and transition form factors (TFF) ($η_c(1S) \rightarrow γγ^*$) for a wide range of photon momentum transfer squared ($Q^2$). The framework for this analysis is provided by a symmetry-preserving Schwinger-Dyson equation (SDE) and Bethe-Salpeter equation (BSE) treatment of a vector$\times$vector contact interaction (CI). We also employ an algebraic model (AM), developed earlier to describe the light quark systems. It correctly correlates infrared and ultraviolet dynamics of quantum chromodynamics (QCD). The CI results agree with the lattice data for low $Q^2$. For $Q^2 \geqslant Q_0^2$, the results start deviating from the lattice results by more than $20 \%$. $Q_0^2 \thickapprox 2.5 {\rm GeV}^2$ for the EFF and $\thickapprox 25 {\rm GeV}^2$ for the TFF. We also present the results for the EFF, TFF as well as $η_c(1S)$ parton distribution amplitude for the AM. Wherever the comparison is possible, these results are in excellent agreement with the lattice, perturbative QCD, the results obtained through an SDE-BSE study, employing refined truncations, as well as the experimental findings of the BABAR experiment.
description: 10 pages, 5 figures, 4 tables. arXiv admin note: text overlap with arXiv:1601.05639
Electronic document interchange integration with application systems
Creators: name: Bland, Suzanne Louise.
Publisher: name: Monash University
Year: 2022

description: This thesis was scanned from the print manuscript for digital preservation and is copyright the author.
 Researchers can access this thesis by asking their local university, institution or public library to
 make a request on their behalf. Monash staff and postgraduate students can use the link in the References field.
Characterizing the feedback of magnetic field on the differential rotation of solar-like stars
Creators: name: Varela, J.
name: Strugarek, A.
name: Brun, A. S.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The aim of this article is to study how the differential rotation of solar-like stars is influenced by rotation rate and mass in presence of magnetic fields generated by a convective dynamo. We use the ASH code to model the convective dynamo of solar-like stars at various rotation rates and masses, hence different effective Rossby numbers. We obtained models with either prograde (solar-like) or retrograde (anti-solar-like) differential rotation. The trends of differential rotation versus stellar rotation rate obtained for simulations including the effect of the magnetic field are weaker compared with hydro simulations ($ΔΩ\propto (Ω/Ω_{\odot})^{0.44}$ in the MHD case and $ΔΩ\propto (Ω/Ω_{\odot})^{0.89}$ in the hydro case), hence showing a better agreement with the observations. Analysis of angular momentum transport revealed that the simulations with retrograde and prograde differential rotation have opposite distribution of the viscous, turbulent Reynolds stresses and meridional circulation contributions. The thermal wind balance is achieved in the prograde cases. However, in retrograde cases Reynolds stresses are dominant for high latitudes and near the top of the convective layer. Baroclinic effects are stronger for faster rotating models.
On the maximum principle for optimal control problems of stochastic Volterra integral equations with delay
Creators: name: Hamaguchi, Yushi
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optimization and Control (math.OC)
subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 93E20, 49K45, 60H20, 26A33

description: In this paper, we prove both necessary and sufficient maximum principles for infinite horizon discounted control problems of stochastic Volterra integral equations with finite delay and a convex control domain. The corresponding adjoint equation is a novel class of infinite horizon anticipated backward stochastic Volterra integral equations. Our results can be applied to discounted control problems of stochastic delay differential equations and fractional stochastic delay differential equations. As an example, we consider a stochastic linear-quadratic regulator problem for a delayed fractional system. Based on the maximum principle, we prove the existence and uniqueness of the optimal control for this concrete example and obtain a new type of explicit Gaussian state-feedback representation formula for the optimal control.
description: 28 pages
Multiple imputation of multilevel missing data: An introduction to the R package pan
Creators: name: Grund, Simon
name: Lüdtke, Oliver
name: Robitzsch, Alexander
Publisher: name: arXiv
Year: 2016
Subjects: subject: Computation (stat.CO)
subject: FOS: Computer and information sciences

description: The treatment of missing data can be difficult in multilevel research because state-of-the-art procedures such as multiple imputation (MI) may require advanced statistical knowledge or a high degree of familiarity with certain statistical software. In the missing data literature, pan has been recommended for MI of multilevel data. In this article, we provide an introduction to MI of multilevel missing data using the R package pan, and we discuss its possibilities and limitations in accommodating typical questions in multilevel research. In order to make pan more accessible to applied researchers, we make use of the mitml package, which provides a user-friendly interface to the pan package and several tools for managing and analyzing multiply imputed data sets. We illustrate the use of pan and mitml with two empirical examples that represent common applications of multilevel models, and we discuss how these procedures may be used in conjunction with other software.
Gravitational microlensing by dressed primordial black holes
Creators: name: Cai, Rong-Gen
name: Chen, Tan
name: Wang, Shao-Jiang
name: Yang, Xing-Yu
Publisher: name: arXiv
Year: 2022
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The accretion of dark matter around the primordial black holes (PBHs) could lead to the formation of surrounding minihalos, whose mass can be several orders of magnitude higher than the central PBH mass. The gravitational microlensing produced by such dressed PBHs could be quite different from that of the bare PBHs, which may significantly affect the constraints on the PBH abundance. In this paper, we study the gravitational microlensing produced by dressed PBHs in detail. We find that all the microlensing effects by dressed PBHs have asymptotic behavior depending on the minihalo size, which can be used to predict the microlensing effects by comparing the halo size with the Einstein radius. When the minihalo radius and the Einstein radius are comparable, the effect of the density distribution of the halo is significant to the microlensing. Applying the stellar microlensing by dressed PBHs to the data of the Optical Gravitational Lensing Experiment and Subaru/HSC Andromeda observations, we obtain the improved constraints on the PBH abundance. It shows that the existence of dark matter minihalos surrounding PBHs can strengthen the constraints on the PBH abundance from stellar microlensing by several orders, and can shift the constraints to the well-known asteroid mass window where PBHs can constitute all the dark matter.
description: 21 pages, 13 figures, add analysis of the wave optics effect and plots of the expected differential event rate, accepted for publication in JCAP
Search for the decay B → ppτν at LHCb
Creators: name: Newcombe, Ryan
Publisher: name: Imperial College London
Year: 2022

description: This work presents a search for the decay B → ppτν using data gathered with the LHCb experiment from 2016 to 2018. No significant signal is observed and a limit is placed on the ratio of branching fractions R(pp) = B → ppτν/B → ppμν < 1.46 at a 95% confidence level, which represents the first limit on a semileptonic ratio of this kind involving decays that are suppressed by the most poorly understood ele- ment of the CKM matrix; Vub. An investigation into the B → pp transition form factors in B → ppℓν decays, which was instrumental in facilitating the search for B → ppτν , is also presented using the 2011–2012 LHCb data sample.
Implementing earned value charts for effective software project monitoring
Creators: name: Tan, Soo Thee.
Publisher: name: Monash University
Year: 2022

description: This thesis was scanned from the print manuscript for digital preservation and is copyright the author.
 Researchers can access this thesis by asking their local university, institution or public library to
 make a request on their behalf. Monash staff and postgraduate students can use the link in the References field.
Spectrally resolved cosmic rays: II -- Momentum-dependent cosmic ray diffusion drives powerful galactic winds
Creators: name: Girichidis, Philipp
name: Pfrommer, Christoph
name: Pakmor, Rüdiger
name: Springel, Volker
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Recently, cosmic ray (CR) feedback has been identified as a critical process in galaxy formation but most previous simulations have integrated out the energy-dependence of the CR distribution, despite its large extent over more than twelve decades in particle energy. To improve upon this simplification, we present the implementation and first application of spectrally resolved CRs which are coupled to the magneto-hydrodynamics in simulations of galaxy formation. The spectral model for the CRs enables more accurate cooling of CRs and allows for an energy-dependent spatial diffusion, for which we introduce a new stable numerical algorithm that proves essential in highly dynamical systems. We perform galaxy formation simulations with this new model and compare the results to a grey CR approach with a simplified diffusive transport and effective cooling that assumes steady-state spectra. We find that the galaxies with spectrally resolved CRs differ in morphology, star formation rate, and strength and structure of the outflows. Interestingly, the first outflow front is driven by CRs with average momenta of $\sim200-600\,\mathrm{Gev}~c^{-1}$. The subsequent formation of outflows, which reach mass loading factors of order unity, are primarily launched by CRs of progressively smaller average momenta of $\sim8-15\,\mathrm{GeV}~c^{-1}$. The CR spectra in the galactic centre quickly approach a steady state, which does not significantly vary over time. In the outer disc and outflow regions, the spectral shape approaches steady state only after $\sim2\,\mathrm{Gyr}$ of evolution. Furthermore, the shapes of the approximate steady state spectra differ for individual regions of the galaxy, which highlights the importance of actively including the full CR spectrum.
description: 21 pages, 13 figures, published in MNRAS, erratum added
Hamilton's equations of motion of a vortex filament in the rotating Bose-Einstein condensate and their "soliton" solutions
Creators: name: Ruban, V. P.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: The equation of motion of a quantized vortex filament in a trapped Bose-Einstein condensate [A. A. Svidzinsky and A. L. Fetter, Phys. Rev. A {\bf 62}, 063617 (2000)] has been generalized to the case of an arbitrary anharmonic anisotropic rotating trap and presented in a variational form. For condensate density profiles of the form $ρ=f(x^2+y^2+\mbox{Re\,}Ψ(x+iy))$ in the presence of the plane of symmetry $y=0$, the solutions $x(z)$ describing stationary vortices of U and S types coming to the surface and solitary waves have been found in quadratures. Analogous three-dimensional configurations of the vortex filament uniformly moving along the $z$ axis have also been found in strictly cylindrical geometry. The dependence of solutions on the form of the function $f(q)$ has been analyzed.
description: 4 pages, 4 figures
Evaluating the Effect of Centralization on Routing Convergence on a Hybrid BGP-SDN Emulation Framework
Creators: name: Gamperli, Adrian
name: Kotronis, Vasileios
name: Dimitropoulos, Xenofontas
Publisher: name: arXiv
Year: 2016
Subjects: subject: Networking and Internet Architecture (cs.NI)
subject: FOS: Computer and information sciences

description: A lot of applications depend on reliable and stable Internet connectivity. These characteristics are crucial for mission-critical services such as telemedical applications. An important factor that can affect connection availability is the convergence time of BGP, the de-facto inter-domain routing (IDR) protocol in the Internet. After a routing change, it may take several minutes until the network converges and BGP routing becomes stable again. Kotronis et al propose a novel Internet routing approach based on SDN principles that combines several Autonomous Systems (AS) into groups, called clusters, and introduces a logically centralized routing decision process for the cluster participants. One of the goals of this concept is to stabilize the IDR system and bring down its convergence time. However, testing whether such approaches can improve on BGP problems requires hybrid SDN and BGP experimentation tools that can emulate multiple ASes. Presently, there is a lack of an easy to use public tool for this purpose. This work fills this gap by building a suitable emulation framework and evaluating the effect that a proof-of-concept IDR controller has on IDR convergence time.
description: Proceedings of ACM SIGCOMM '14, pages 369-370, 1/1/2015
Growth of Sobolev norms and loss of regularity in transport equations
Creators: name: Crippa, Gianluca
name: Elgindi, Tarek
name: Iyer, Gautam
name: Mazzucato, Anna L.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: We consider transport of a passive scalar advected by an irregular divergence free vector field. Given any non-constant initial data $\bar ρ\in H^1_\text{loc}({\mathbb R}^d)$, $d\geq 2$, we construct a divergence free advecting velocity field $v$ (depending on $\bar ρ$) for which the unique weak solution to the transport equation does not belong to $H^1_\text{loc}({\mathbb R}^d)$ for any positive positive time. The velocity field $v$ is smooth, except at one point, controlled uniformly in time, and belongs to almost every Sobolev space $W^{s,p}$ that does not embed into the Lipschitz class. The velocity field $v$ is constructed by pulling back and rescaling an initial data dependent sequence of sine/cosine shear flows on the torus. This loss of regularity result complements that in [Ann. PDE, 5(1):Paper No. 9, 19, 2019].
Nature of a single doped hole in two-leg Hubbard and $t$-$J$ ladders
Creators: name: Liu, Shenxiu
name: Jiang, Hong-Chen
name: Devereaux, Thomas P.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: In this paper, we have systematically studied the single hole problem in two-leg Hubbard and $t$-$J$ ladders by large-scale density-matrix renormalization group calculations. We found that the doped hole in both models behaves similarly with each other while the three-site correlated hopping term is not important in determining the ground state properties. For more insights, we have also calculated the elementary excitations, i.e., the energy gaps to the excited states of the system. In the strong rung limit, we found that the doped hole behaves as a Bloch quasiparticle in both systems where the spin and charge of the doped hole are tightly bound together. In the isotropic limit, while the hole still behaves like a quasiparticle in the long-wavelength limit, its spin and charge components are only loosely bound together with a nontrivial mutual statistics inside the quasiparticle. Our results show that this mutual statistics can lead to an important residual effect which dramatically changes the local structure of the ground state wavefunction.
On the Wegner orbital model
Creators: name: Schenker, Jeffrey
name: Peled, Ron
name: Shamis, Mira
name: Sodin, Sasha
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mathematical Physics (math-ph)
subject: Probability (math.PR)
subject: Spectral Theory (math.SP)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: The Wegner orbital model is a class of random operators introduced by Wegner to model the motion of a quantum particle with many internal degrees of freedom (orbitals) in a disordered medium. We consider the case when the matrix potential is Gaussian, and prove three results: localisation at strong disorder, a Wegner-type estimate on the mean density of eigenvalues, and a Minami-type estimate on the probability of having multiple eigenvalues in a short interval. The last two results are proved in the more general setting of deformed block-Gaussian matrices, which includes a class of Gaussian band matrices as a special case. Emphasis is placed on the dependence of the bounds on the number of orbitals. As an additional application, we improve the upper bound on the localisation length for one-dimensional Gaussian band matrices.
description: 23 pages
The effect of team role on balanced team formation
Creators: name: Khoo, Annabel Mong Yee.
Publisher: name: Monash University
Year: 2022

description: This thesis was scanned from the print manuscript for digital preservation and is copyright the author.
 Researchers can access this thesis by asking their local university, institution or public library to
 make a request on their behalf. Monash staff and postgraduate students can use the link in the References field.