cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Avatar Work: Telework for Disabled People Unable to Go Outside by Using Avatar Robots "OriHime-D" and Its Verification
Creators: name: Takeuchi, Kazuaki
name: Yamazaki, Yoichi
name: Yoshifuji, Kentaro
Publisher: name: arXiv
Year: 2020
Subjects: subject: Robotics (cs.RO)
subject: Computers and Society (cs.CY)
subject: Human-Computer Interaction (cs.HC)
subject: Social and Information Networks (cs.SI)
subject: FOS: Computer and information sciences

description: In this study, we propose a telework "avatar work" that enables people with disabilities to engage in physical works such as customer service in order to realize an inclusive society, where we can do anything if we have free mind, even though we are bedridden. In avatar work, disabled people can remotely engage in physical work by operating a proposed robot "OriHime-D" with a mouse or gaze input depending on their own disabilities. As a social implementation initiative of avatar work, we have opened a two-week limited avatar robot cafe and have evaluated remote employment by people with disabilities using OriHime-D. As the results by 10 people with disabilities, we have confirmed that the proposed avatar work leads to mental fulfillment for people with disparities, and can be designed with adaptable workload. In addition, we have confirmed that the work content of the experimental cafe is appropriate for people with a variety of disabilities seeking social participation. This study contributes to fulfillment all through life and lifetime working, and at the same time leads to a solution to the employment shortage problem.
description: 8 pages, 16 figures, accepted to the 2020 ACM/IEEE International Conference on Human-Robot Interaction (HRI '20 Companion) at alt.HRI session, 2020
Early newborn care practices and the development and functionality of the human microbiome
Creators: name: Jenkins, Holly Jasmine
Publisher: name: Imperial College London
Year: 2018

description: Background: The protease family, a group of enzymes produced by the host and bacterial species, play important roles in maintaining the homeostasis of the intestinal barrier. The concentrations of major gastrointestinal proteases including; pepsin, trypsin, and chymotrypsin, have been measured in preterm neonates. However, their longitudinal development is not well described. This thesis aims to investigate the dynamics of proteases, relate activity to disease and bacterial colonisation and measure their impact in vitro in a neonatal cohort. Methods: Daily faecal and ileostomy samples were collected from birth until discharge or death in 66 preterm neonates born before 32 weeks’ gestation. Substrate and inhibitor-based assays were applied to profile total protease activity (ng/µL trypsin equivalent (TE)) in 20 control neonates, three surgically confirmed necrotising enterocolitis (NEC) cases, one spontaneous intestinal perforation (SIP) case, one intestinal atresia case, and three culture confirmed septicaemia cases. Postnatal colonisation of the intestinal tract was followed in 15 neonates by metataxonomic analysis. The proteolytic impact on the intestinal barrier was assessed in a Caco-2 cell model. Results: Control, NEC/SIP and septicaemia neonates were characterised by patterns of high and low proteolytic activities. Activity increased with postmenstrual age only in control neonates (p<0.05). Inhibitor analysis revealed faecal and ileostomy samples were characterised by serine and cysteine proteases. Colonisation was irregular and dominated by genera that were not influenced by postnatal age, mode of delivery or feeding regimen. Correlation analysis revealed positive associations between Clostridium sensu stricto and Corynebacterium genera and faecal and ileostomy proteolytic activity (p <0.05). Caco-2 cell exposure to samples with low protease activity (< 250 ng/µL TE) led to a greater decrease in transepithelial electrical resistance. Conclusions: Having established that proteases are present and active during the early neonatal period; this thesis provides the scope to continue investigating their associations with bacteria and their roles in neonatal diseases.
THE EFFECT OF DEBT BURDEN, INTEREST RATES AND INFLATION ON THE SURVIVAL OF FARMING ENTERPRISES: A CASE STUDY IN THE WESTERN TRANSVAAL AND THE NORTH-WESTERN BUSHVELD
Creators: name: Van Zyl, J.
name: Van Der Vyver, A.
name: Mostert, C. W.
name: Van Zyl, J.
name: Van Der Vyver, A.
name: Mostert, C. W.
Publisher: name: Unknown
Year: 1987
Subjects: Agricultural Finance
Financial Economics

description: In this study the effect of varying yield levels (drought), structural input price inflation, interest rates and initial solvency position (as influenced by debt burden) on typical farming enterprises in the Western Transvaal and the North-western Transvaal Bushveld is determined. Initial solvency situation, interest rates and structural inflation have a significant effect on financial results of farming enterprises. Analysis of variance shows that these three factors and their effects are interdependent. The effect and influence of each on survival are therefore influenced by the levels of the other factors. Consequently all three factors must be influenced simultaneously in order to obtain positive results with regard to the survival of farming enterprises in the Western Transvaal and the North-western Transvaal Bushveld.
Modelling and inference of spatio-temporal processes in Single Molecule Localisation Microscopy
Creators: name: Patel, Lekha
Publisher: name: Imperial College London
Year: 2019

description: Recent advancements in super-resolution microscopy have enabled cellular structures to be imaged beyond sub-diffraction limits. In order to do so, a widely used class of super resolution methods called single molecule localisation microscopy (SMLM) exploit the stochastic nature of fluorescent probes, or fluorophores, that move between bright and dark states until they permanently cease to transition. When observing a large number of fluorophores, this behaviour enables only a sparse subset of them to be detected at any one time, resulting in the ability to accurately record and accumulate their spatial measurements to produce a super-resolved image. While this stochastic behaviour has been heavily exploited, it induces multiple localisations per molecule which gives rise to misleading representations of the true structures of interest. Accurate quantification of the underlying photo-kinetic behaviour is therefore required before any spatial analysis can be conducted. In this thesis, we model the photo-kinetic behaviour of a molecule as a continuous time Markov process that can transition between a photo-emitting On state, several (unknown) non-photon emitting dark states and an permanently dark state. From this, we develop the Photo-Switching Hidden Markov Model (PSHMM) which relates this underlying behaviour to an observed signal indicating whether or not a molecule is detected in a given frame. Under this model, we derive a maximum likelihood estimator which is used to estimate the unknown transition rates and photo-kinetic model. Under different experimental conditions, the statistical properties of this estimator are also investigated. When an unknown number of fluorescing molecules is filmed, the PSHMM set-up subsequently allows us to derive the distribution of the total number of observed localisations in an experiment, from which an accurate molecular counting tool can be constructed. Finally, we formulate true molecular positions as a spatio-temporal hidden point process and describe the observation process it generates at each time step. The full Bayes filter is then derived, from which the point process and static parameters of the model can be inferred using Markov Chain Monte Carlo (MCMC).
Roundup Use on UBC Campus
Creators: name: Dominik, Magda
Publisher: name: The University of British Columbia
Year: 2010

description: Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions, conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report and is not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status of activities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the current status of the subject matter of a project/report.”
Brane Cosmology with Matter in the Bulk. I
Creators: name: Apostolopoulos, Pantelis S.
name: Tetradis, Nikolaos
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Astrophysics (astro-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We derive exact solutions of the Einstein equations in the context of the Randall-Sundrum model with matter both on the brane and in the bulk. The bulk metric is a generalization of the static metrics describing the interior of stellar objects. We study the cosmological evolution on the brane. Our solutions describe energy ouflow from the brane, and the appearance of ``mirage'' contributions to the Hubble expansion that alter the standard cosmological evolution.
description: Latex, 13 pages, no figures; some new references added; minor changes to match published version in Class. Quantum Grav. (uses iopart style/class files)
Kemeny, G., 2004. A nyomozó hatóságok általános illetékességi problémái az új Be. kapcsán. Magyar Rendészet (4)3, pp. 99-104.
Creators: name: Kemeny, Gabor
Publisher: name: figshare
Year: 2020
Subjects: subject: 180110 Criminal Law and Procedure
subject: FOS: Law

description: Contradictions in the regulations on the authority and jurisdiction of the Hungarian police service.
Propagation of Light in Doubly Special Relativity
Creators: name: Kim, Sung Ku
name: Kim, Sun Myong
name: Rim, Chaiho
name: Yee, Jae Hyung
Publisher: name: arXiv
Year: 2004
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In an attempt to clarify what is the velocity of a particle in doubly special relativity, we solve Maxwell's equations invariant under the position-space nonlinear Lorentz transformation proposed by Kimberly, Magueijo, and Medeiros. We show that only the amplitude of the Maxwell wave, not the phase, is affected by the nonlinearity of the transformation. Thus, although the Maxwell wave appears to have infinitely large energy near the Planck time, the wave velocity is the same as the conventional light velocity. Surprisingly, the velocity of the Maxwell wave is not the same as the maximum signal velocity determined by the null geodesic condition, which is infinitely large near the Planck time and monotonically decreases in time to the conventional light velocity when time approaches infinity. This implies that, depending on the position of the particle in question, the light cone determined by Maxwell's equations may be inside or outside the null cone determined by the null geodesic equation, which may lead to the causality problem.
description: 11 pages, LaTeX
The Northern Cross Fast Radio Burst project. I. Overview and pilot observations at 408 MHz
Creators: name: Locatelli, Nicola T.
name: Bernardi, Gianni
name: Bianchi, Germano
name: Chiello, Riccardo
name: Magro, Alessio
name: Naldi, Giovanni
name: Pilia, Maura
name: Pupillo, Giuseppe
name: Ridolfi, Alessandro
name: Setti, Giancarlo
name: Vazza, Franco
Publisher: name: arXiv
Year: 2020
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Fast radio bursts remain one of the most enigmatic astrophysical sources. Observations have significantly progressed over the last few years, thanks to the capabilities of new radio telescopes and the refurbishment of existing ones. Here we describe the upgrade of the Northern Cross radio telescope, operating in the 400-416~MHz frequency band, with the ultimate goal of turning the array into a dedicated instrument to survey the sky for fast radio bursts. We present test observations of the pulsar B0329+54 to characterize the system performance and forecast detectability. Observations with the system currently in place are still limited by modest sky coverage ($\sim 9.4$~deg$^2$) and biased by smearing of high dispersion measure events within each frequency channels. In its final, upgraded configuration, however, the telescope will be able to carry out unbiased fast radio burst surveys over a $\sim 350$~deg$^2$ instantaneous field of view up to $z \sim 5$, with a (nearly constant) $\sim 760 \, (τ/{\rm ms})^{-0.5}$~mJy rms sensitivity.
description: 8 pages, 9 figures, accepted by MNRAS
Safe and accurate MAV Control, navigation and manipulation
Creators: name: Tzoumanikas, Dimosthenis
Publisher: name: Imperial College London
Year: 2020

description: This work focuses on the problem of precise, aggressive and safe Micro Aerial Vehicle (MAV) navigation as well as deployment in applications which require physical interaction with the environment. To address these issues, we propose three different MAV model based control algorithms that rely on the concept of receding horizon control. As a starting point, we present a computationally cheap algorithm which utilizes an approximate linear model of the system around hover and is thus maximally accurate for slow reference maneuvers. Aiming at overcoming the limitations of the linear model parameterisation, we present an extension to the first controller which relies on the true nonlinear dynamics of the system. This approach, even though computationally more intense, ensures that the control model is always valid and allows tracking of full state aggressive trajectories. The last controller addresses the topic of aerial manipulation in which the versatility of aerial vehicles is combined with the manipulation capabilities of robotic arms. The proposed method relies on the formulation of a hybrid nonlinear MAV-arm model which also takes into account the effects of contact with the environment. Finally, in order to enable safe operation despite the potential loss of an actuator, we propose a supervisory algorithm which estimates the health status of each motor. We further showcase how this can be used in conjunction with the nonlinear controllers described above for fault tolerant MAV flight. While all the developed algorithms are formulated and tested using our specific MAV platforms (consisting of underactuated hexacopters for the free flight experiments, hexacopter-delta arm system for the manipulation experiments), we further discuss how these can be applied to other underactuated/overactuated MAVs and robotic arm platforms. The same applies to the fault tolerant control where we discuss different stabilisation techniques depending on the capabilities of the available hardware. Even though the primary focus of this work is on feedback control, we thoroughly describe the custom hardware platforms used for the experimental evaluation, the state estimation algorithms which provide the basis for control as well as the parameter identification required for the formulation of the various control models. We showcase all the developed algorithms in experimental scenarios designed to highlight the corresponding strengths and weaknesses as well as show that the proposed methods can run in realtime on commercially available hardware.
Extended molecules and geometric scattering resonances in optical lattices
Creators: name: Fedichev, P. O.
name: Bijlsma, M. J.
name: Zoller, P.
Publisher: name: arXiv
Year: 2003
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We develop a theory describing neutral atoms scattering at low energies in an optical lattice. We show that for a repulsive interaction, as the microscopic scattering length increases, the effective scattering amplitude approaches a limiting value which depends only on the lattice parameters. In the case of attractive interaction a geometric resonance occurs before reaching this limit. Close to the resonance, the effective interaction becomes repulsive and supports a weakly bound state, which can extend over several lattice sites.
description: 4 pages, 1 figure, RevTeX
The role of dust in "active" and "passive" low-metallicity star formation
Creators: name: Hirashita, H.
name: Hunt, L. K.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We investigate the role of dust in star formation activity of extremely metal-poor blue compact dwarf galaxies (BCDs). Observations suggest that star formation in BCDs occurs in two different regimes: "active" and "passive". The "active" BCDs host super star clusters (SSCs), and are characterised by compact size, rich H2 content, large dust optical depth, and high dust temperature; the "passive" BCDs are more diffuse with cooler dust, and lack SSCs and large amounts of H2. By treating physical processes concerning formation of stars and dust, we are able to simultaneously reproduce all the above properties of both modes of star formation (active and passive). We find that the difference between the two regimes can be understood through the variation of the "compactness" of the star-forming region: an "active" mode emerges if the region is compact (with radius $\la 50$ pc) and dense (with gas number density $\ga 500$ cm$^{-3}$). The dust, supplied from Type II supernovae in a compact star-forming region, effectively reprocesses the heating photons into the infrared and induces a rapid H2 formation over a period of several Myr. This explains the high infrared luminosity, high dust temperature, and large H2 content of active BCDs. Moreover, the gas in "active" galaxies cools ($\la 300$ K) on a few dynamical timescales, producing a "run-away" star formation episode because of the favourable (cool) conditions. The mild extinction and relatively low molecular content of passive BCDs can also be explained by the same model if we assume a diffuse region (with radius $\ga 100$ pc and gas number density $\la 100$ cm$^{-3}$). We finally discuss primordial star formation in high-redshift galaxies in the context of the "active" and "passive" star formation scenario.
description: Astronomy and Astrophysics, in press, 16 pages, 8 figures
Reproducing the Universe: a comparison between the EAGLE simulations and the nearby DustPedia galaxy sample
Creators: name: Trčka, Ana
name: Baes, Maarten
name: Camps, Peter
name: Meidt, Sharon E.
name: Trayford, James
name: Bianchi, Simone
name: Casasola, Viviana
name: Cassarà, Letizia P.
name: De Looze, Ilse
name: De Vis, Pieter
name: Dobbels, Wouter
name: Fritz, Jacopo
name: Galametz, Maud
name: Galliano, Frédéric
name: Katsianis, Antonios
name: Madden, Suzanne C.
name: Mosenkov, Aleksandr V.
name: Nersesian, Angelos
name: Viaene, Sébastien
name: Xilouris, Emmanuel M.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We compare the spectral energy distributions (SEDs) and inferred physical properties for simulated and observed galaxies at low redshift. We exploit UV-submillimetre mock fluxes of ~7000 z=0 galaxies from the EAGLE suite of cosmological simulations, derived using the radiative transfer code SKIRT. We compare these to ~800 observed galaxies in the UV-submillimetre range, from the DustPedia sample of nearby galaxies. To derive global properties, we apply the SED fitting code CIGALE consistently to both data sets, using the same set of ~80 million models. The results of this comparison reveal overall agreement between the simulations and observations, both in the SEDs and in the derived physical properties, with a number of discrepancies. The optical and far-infrared regimes, and the scaling relations based upon the global emission, diffuse dust and stellar mass, show high levels of agreement. However, the mid-infrared fluxes of the EAGLE galaxies are overestimated while the far-UV domain is not attenuated enough, compared to the observations. We attribute these discrepancies to a combination of galaxy population differences between the samples, and limitations in the subgrid treatment of star-forming regions in the EAGLE-SKIRT post-processing recipe. Our findings show the importance of detailed radiative transfer calculations and consistent comparison, and provide suggestions for improved numerical models.
description: 17 pages, 14 figures, accepted for publication in MNRAS
Chemical proteomics approaches for the identification of the targets of small molecule inflammasome inhibitors
Creators: name: Kennedy, Cassandra Ruth
Publisher: name: Imperial College London
Year: 2020

description: Pyroptosis is a type of programmed cell death that occurs in macrophages and neutrophils during caspase-1 driven inflammatory responses. During this process, caspase-1 is activated via a large protein scaffold known as an inflammasome. Disruption of this pathway can lead to chronic inflammation, and so inhibitors of this pathway are of clinical interest. A specific inhibitor of the NLRP3 inflammasome, MCC950, has shown promise in animal models for, among others, atherosclerosis, Alzheimer’s disease and heart disease, however until recently the target protein of this drug was unknown. This thesis reports the use of a powerful chemical proteomic technique for MCC950 target and off-target protein identification, and discusses the design, synthesis and validation of two photo-crosslinkable probes. These probes utilize diazirine photo-reactivity and alkyne-azide ‘click’ reactivity, enabling labelled proteins to be distinguished through mass spectrometry and proteomic analysis. Affinity-based protein profiling (AfBPP) is used here in intact cells to confirm NLRP3 as the target protein of MCC950, and to identify novel off-target proteins for the molecule. In parallel, this thesis reports the development of a proteomics-led cellular thermal shift assay (CETSA) technique which identifies proteins stabilised upon small molecule binding. This method is used in intact cells with MCC950 to validate novel off-target proteins discovered through affinity-based protein profiling.
Hardware Efficient Quantum Algorithms for Vibrational Structure Calculations
Creators: name: Ollitrault, Pauline J.
name: Baiardi, Alberto
name: Reiher, Markus
name: Tavernelli, Ivano
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We introduce a framework for the calculation of ground and excited state energies of bosonic systems suitable for near-term quantum devices and apply it to molecular vibrational anharmonic Hamiltonians. Our method supports generic reference modal bases and Hamiltonian representations, including the ones that are routinely used in classical vibrational structure calculations. We test different parametrizations of the vibrational wave function, which can be encoded in quantum hardware, based either on heuristic circuits or on the bosonic Unitary Coupled Cluster Ansatz. In particular, we define a novel compact heuristic circuit and demonstrate that it provides the best compromise in terms of circuit depth, optimization costs, and accuracy. We evaluate the requirements, number of qubits and circuit depth, for the calculation of vibrational energies on quantum hardware and compare them with state-of-the-art classical vibrational structure algorithms for molecules with up to seven atoms.
Climate, air quality and health impacts of transport policies in cities
Creators: name: Calderon-Irazoque, Andrea
Publisher: name: Imperial College London
Year: 2020

description: Environmental policies in cities have failed to effectively reduce air pollutants and greenhouse gas emissions to levels not detrimental to our environment and the health of the rapidly growing urban population. Most of the air pollutants originate from the same sources as greenhouse gases; the burning of fossil fuels and the urban transport sector are significant emitters of both. This dissertation examines the interactions between measures designed to tackle air pollution and reduce CO2 emissions in the transport sector in cities, with London and Mexico City as case study cities. Transport policies proposed for London by its authorities were reviewed, and from them, transport policy scenarios were developed and modelled. Technological and behavioural change transport policy scenarios were studied, including the implementation of low emission zones, vehicle electrification, reduction of car use through the promotion of active travel modes, and construction of cycle lanes. The BRUTAL sub-model of the UK Integrated Assessment Model was used to estimate CO2 emissions and air pollutants (NOX, NO2, PM10 and PM2.5) emissions and concentrations projected to 2030. Monetised benefits for the reduction in exposure to air pollution and the offset price for CO2 mitigation were calculated. For Mexico City, a more straightforward approach was used, assessing data from the emissions inventory to explore which strategies might be useful in reducing emissions from road transport. Health impact assessment approach was used to estimate the health impacts of air pollution exposure and physical activity in both cities. Technological strategies are effective at reducing NOX pollution and CO2 emission. Behavioural change strategies yield significant reductions in particulate matter pollution. Behavioural change scenarios also deliver the most significant health benefits through an increase in physical activity. For Mexico City, the renewal of the old vehicle fleet could bring significant air pollutant emissions reductions. Future work should assess the feasibility of the scenarios.
Thermal states of coldest and hottest neutron stars in soft X-ray transients
Creators: name: Yakovlev, D. G.
name: Levenfish, K. P.
name: Potekhin, A. Y.
name: Gnedin, O. Y.
name: Chabrier, G.
Publisher: name: arXiv
Year: 2003
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We calculate the thermal structure and quiescent thermal luminosity of accreting neutron stars (warmed by deep crustal heating in accreted matter) in soft X-ray transients (SXTs). We consider neutron stars with nucleon and hyperon cores and with accreted envelopes. It is assumed that an envelope has an outer helium layer (of variable depth) and deeper layers of heavier elements, either with iron or with much heavier nuclei (of atomic weight A > 100) on the top (Haensel & Zdunik 1990, 2003, astro-ph/0305220). The relation between the internal and surface stellar temperatures is obtained and fitted. The quiescent luminosity of the hottest (low-mass) and coldest (high-mass) neutron stars is calculated, together with the ranges of its possible variations due to variable thickness of the helium layer. The results are compared with observations of SXTs, particularly, containing the coldest (SAX J1808.4-3658) and the hottest (Aql X-1) neutron stars. The observations of SAX J1808.4-3658 in a quiescent state on March 24, 2001 (Campana et al. 2002, astro-ph/0206376) can be explained only if this SXT contains a massive neutron star with a nucleon/hyperon core; a hyperon core with a not too low fraction of electrons is preferable. Future observations may discriminate between the various models of hyperon/nucleon dense matter. The thermal emission of SAX J1808.4-3658 is also sensitive to the models of plasma ionization in the outermost surface layers and can serve for testing such models.
description: 12 pages, 5 figures, 4 tables, LaTeX2e with aa.cls v.5.3 (included). Accepted by A&A
Protoplanetary Disks in the Orion Nebula Cluster: Gas Disk Morphologies and Kinematics as seen with ALMA
Creators: name: Boyden, Ryan D.
name: Eisner, Josh A.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present Atacama Large Millimeter Array CO(3$-$2) and HCO$^+$(4$-$3) observations covering the central $1\rlap{.}'5$$\times$$1\rlap{.}'5$ region of the Orion Nebula Cluster (ONC). The unprecedented level of sensitivity ($\sim$0.1 mJy beam$^{-1}$) and angular resolution ($\sim$$0\rlap{.}''09 \approx 35$ AU) of these line observations enable us to search for gas-disk detections towards the known positions of submillimeter-detected dust disks in this region. We detect 23 disks in gas: 17 in CO(3$-$2), 17 in HCO$^+$(4$-$3), and 11 in both lines. Depending on where the sources are located in the ONC, we see the line detections in emission, in absorption against the warm background, or in both emission and absorption. We spectrally resolve the gas with $0.5$ km s$^{-1}$ channels, and find that the kinematics of most sources are consistent with Keplerian rotation. We measure the distribution of gas-disk sizes and find typical radii of $\sim$50-200 AU. As such, gas disks in the ONC are compact in comparison with the gas disks seen in low-density star-forming regions. Gas sizes are universally larger than the dust sizes. However, the gas and dust sizes are not strongly correlated. We find a positive correlation between gas size and distance from the massive star $θ^1$ Ori C, indicating that disks in the ONC are influenced by photoionization. Finally, we use the observed kinematics of the detected gas lines to model Keplerian rotation and infer the masses of the central pre-main-sequence stars. Our dynamically-derived stellar masses are not consistent with the spectroscopically-derived masses, and we discuss possible reasons for this discrepancy.
description: 42 pages, 31 figures
Phase coherence, visibility, and the superfluid--Mott-insulator transition on one-dimensional optical lattices
Creators: name: Sengupta, P.
name: Rigol, M.
name: Batrouni, G. G.
name: Denteneer, P. J. H.
name: Scalettar, R. T.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: We study the phase coherence and visibility of trapped atomic condensates on one-dimensional optical lattices, by means of quantum Monte-Carlo simulations. We obtain structures in the visibility similar to the kinks recently observed experimentally by Gerbier et.al.[Phy. Rev. Lett. 95, 050404 (2005); Phys. Rev. A 72, 053606 (2005)]. We examine these features in detail and offer a connection to the evolution of the density profiles as the depth of the lattice is increased. Our simulations reveal that as the interaction strength, U, is increased, the evolution of superfluid and Mott-insulating domains stall for finite intervals of U. The density profiles do not change with increasing U. We show here that in one dimension the visibility provides unequivocal signatures of the melting of Mott domains with densities larger than one.
description: 4 pages, 5 figures
Semiclassical action based on dynamical mean-field theory describing electrons interacting with local lattice fluctuations
Creators: name: Blawid, Stefan
name: Zwicknagl, Gertrud
Publisher: name: arXiv
Year: 2003
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We extend a recently introduced semiclassical approach to calculating the influence of local lattice fluctuations on electronic properties of metals and metallic molecular crystals. The effective action of electrons in degenerate orbital states coupling to Jahn-Teller distortions is derived, employing dynamical mean-field theory and adiabatic expansions. We improve on previous numerical treatments of the semiclassical action and present for the simplifying Holstein model results for the finite temperature optical conductivity at electron-phonon coupling strengths from weak to strong. Significant transfer of spectral weight from high to low frequencies is obtained on isotope substitution in the Fermi-liquid to polaron crossover regime.
description: 10 pages, 7 figures
title: Modelling the behaviour of granular material on the surface of asteroids and under different gravity conditions (e.g., Mars, the Moon)
Creators: name: Murdoch, Naomi
Publisher: name: The Open University
Year: 2011

description: This thesis, at the interface between the scientific disciplines of planetary science and granular physics, has two key components, both of which intend to increase our understanding of granular dynamics in varying gravitational conditions. The dynamics of granular materials are involved in the evolution of solid planets and small bodies in our Solar System, whose surfaces are generally covered with regolith. Understanding granular dynamics is also critical for the design and/or operations of landers, sampling devices and rovers to be included in space missions. The first component of this thesis is the validation of the hard-sphere discrete element method implementation in the N-body code pkdgrav to model the dynamics of granular material. By direct comparison with results from laboratory experiments, it is demonstrated that the hard-sphere discrete element method implementation in pkdgrav is valid for modelling granular material in dilute regimes and is capable of reproducing the complex dynamical behaviour of a specific dense system as well. The second component is focussed on the AstEx parabolic flight experiment. This experiment, with the aim of characterising the response of granular material to rotational shear forces in a microgravity environment, was designed, constructed, flown and the data were analysed as part of this thesis. It was found that the effect of constant shearing on a granular material in a direction perpendicular to the gravity field is not strongly influenced by gravity. The AstEx experiment has demonstrated, for the first time, that the efficiency of granular convection may decrease in the presence of a weak gravitational field, similar to that on the surface of small bodies. The first measurements of transient weakening of granular material after shear reversal in microgravity are also reported. Results suggest that the force contact network may be weaker in microgravity, although the influence of any change in the contact network is felt by the granular material over much larger distances. This may have important implications for our interpretation of asteroid surfaces. Continued advancement of our understanding of granular materials in varying gravitational conditions requires futher experiments and the development of the soft-sphere discrete element method implementation in pkdgrav in order to model the granular regimes that are inaccessbile to the hard-sphere implementation.
Emissions Trading: A Feasible Analysis for UBC
Creators: name: Chisholm, Jeff
name: Hoffman, Vivian
Publisher: name: The University of British Columbia
Year: 2010

description: Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions, conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report and is not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status of activities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the current status of the subject matter of a project/report.”
Perturbing General Uncorrelated Networks
Creators: name: Burda, Z.
name: Jurkiewicz, J.
name: Krzywicki, A.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: This paper is a direct continuation of an earlier work, where we studied Erdös-Rényi random graphs perturbed by an interaction Hamiltonian favouring the formation of short cycles. Here, we generalize these results. We keep the same interaction Hamiltonian but let it act on general graphs with uncorrelated nodes and an arbitrary given degree distribution. It is shown that the results obtained for Erdös-Rényi graphs are generic, at the qualitative level. However, scale-free graphs are an exception to this general rule and exhibit a singular behaviour, studied thoroughly in this paper, both analytically and numerically.
description: 7 pages, 7 eps figures, 2-column revtex format, references added
Smallholders' food security between farming and migration. Evidence from five Northern and Eastern African countries
Creators: name: Piras, Simone
name: Mulazzani, Luca
name: Barlagne, Carla
name: Nchimbi-Msolla, Susan
name: Mwanri, Akwilina
name: Ddungu, Richard
name: Ogenrwoth, Brian
name: Hanafi, Anissa
name: Chimoita, Evans Ligare
name: Kapour, Gurneet
name: Setti, Marco
Publisher: name: Zenodo
Year: 2025
Subjects: household model
food security
migration
remittances
smallholder farming
Africa

description: In developing countries, the relationship between migration, agriculture, and food security is characterised by complex feedback loops. In the absence of working markets, consumption and production decisions are inseparable. We develop a theoretical model where smallholders maximise food security by allocating labour to farming or migration, and farm production to self-consumption or sales, subject to remittance and farm production functions and a cash constraint. We estimate the model empirically by applying three-stage-least-squares to an original dataset of 5,300 crop and fish farmers from five African countries. We found that self-consumption improves food security, but larger benefits are generated by cash income, which in turn is positively related to farm sales. Reduction of household members through migration improves food security but the impact of remittance investment is unclear, as confirmed by a propensity score matching analysis. Our findings suggest prioritising cash crops, loss reduction, and productivity increase to invest labour off-farm.
$J$-factor estimation of Draco, Sculptor and Ursa Minor dwarf spheroidal galaxies with the member/foreground mixture model
Creators: name: Horigome, Shun-ichi
name: Hayashi, Kohei
name: Ibe, Masahiro
name: Ishigaki, Miho N.
name: Matsumoto, Shigeki
name: Sugai, Hajime
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Dwarf spheroidal galaxies (dSphs) are promising targets of indirect detection experiments searching for dark matter (DM) at present universe. Toward robust prediction for the amount of signal flux originating in DM annihilation inside dSphs, a precise determination of DM distributions as well as $J$-factors of the dSphs is particularly important. In this work, we estimate those of Draco, Sculptor, and Ursa Minor dSphs by an improved statistical method in which both foreground stars and dSph member stars are simultaneously taken into account. We define the likelihood function of the method as the so-called conditional one to remove sampling bias of observed stellar data. This improved method enables us to estimate DM distributions and $J$-factors of the dSphs directly from observed stellar data contaminated by foreground stars without imposing stringent membership criteria on the measured quantities.
description: 13 pages, 13 figures, 3 tables. Submitted to MNRAS
Network analysis for international relations
Creators: name: Hafner-Burton, Emilie M.
name: Kahler, Miles
name: Montgomery, Alexander H.
Publisher: name: International Organization
Year: 2023
Subjects: classificationCode: 4408
subject: Political science
subject: FOS: Political science

description: International relations research has regarded networks as a particular mode of organization, distinguished from markets or state hierarchies. In contrast, network analysis permits the investigation and measurement of network structures – emergent properties of persistent patterns of relations among agents that can define, enable, and constrain those agents. Network analysis offers both a toolkit for identifying and measuring the structural properties of networks and a set of theories, typically drawn from contexts outside international relations, that relate structures to outcomes. Network analysis challenges conventional views of power in international relations by defining network power in three different ways: social power (connectedness), brokerage, and exit options. Two issues are particularly important to international relations: the ability of actors to increase their power by enhancing and exploiting their network positions, and the fungibility of network power. The value of network analysis in international relations has been demonstrated in precise description of international networks, investigation of network effects on key international outcomes, testing of existing network theory in the context of international relations, and development of new sources of data. Partial or faulty incorporation of network analysis, however, risks trivial conclusions, unproven assertions, and measures without meaning. A three-part agenda is proposed for future application of network analysis to international relations: import the toolkit to deepen research on international networks; test existing network theories in the domain of international relations; and test international relations theories using the tools of network analysis.
Network analysis for international relations
Creators: name: Hafner-Burton, Emilie M.
name: Kahler, Miles
name: Montgomery, Alexander H.
Publisher: name: American University
Year: 2023

description: International relations research has regarded networks as a particular mode of organization, distinguished from markets or state hierarchies. In contrast, network analysis permits the investigation and measurement of network structures – emergent properties of persistent patterns of relations among agents that can define, enable, and constrain those agents. Network analysis offers both a toolkit for identifying and measuring the structural properties of networks and a set of theories, typically drawn from contexts outside international relations, that relate structures to outcomes. Network analysis challenges conventional views of power in international relations by defining network power in three different ways: social power (connectedness), brokerage, and exit options. Two issues are particularly important to international relations: the ability of actors to increase their power by enhancing and exploiting their network positions, and the fungibility of network power. The value of network analysis in international relations has been demonstrated in precise description of international networks, investigation of network effects on key international outcomes, testing of existing network theory in the context of international relations, and development of new sources of data. Partial or faulty incorporation of network analysis, however, risks trivial conclusions, unproven assertions, and measures without meaning. A three-part agenda is proposed for future application of network analysis to international relations: import the toolkit to deepen research on international networks; test existing network theories in the domain of international relations; and test international relations theories using the tools of network analysis.
Preliminary study on the effect of LED light and cytokinine on the growth of pear plants in vitro
Creators: name: Dimitrova N., Nacheva L.
Publisher: name: Zenodo
Year: 2021

description: In the past two decades, light emitting diodes (LED) have become an alternative source of light for plant tissue culture, due to their low energy consumption, low heat emission, specific wavelength irradiation etc. The effect of three LED lights (white, blue and mixed) and two cytokinines (6-benzylaminopurine or meta-Topolin) on the growth of pear (Pyrus communis L. ‘OHF 333’) in vitro was studied. The plantlets were cultivated in microboxes (SacO2, Belgium) on a modified MS (Murashige and Skoog, 1962) solid medium supplemented with 2.5 µM 6-benzylaminopurine (BAP) or meta-Topolin (mT). The plantlets were grown in controlled room using Philips GreenPower LED research module. Three groups of LEDs emitting in white (W), blue (B), mixed (W:R:B:far-red=1:1:1:1) (BR) lights were applied. Biometric parameters, content of photosynthetic pigments and gas-exchange analysis of the plants were measured after three four weeks passages under corresponding light/cytokinine treatment. The results obtained indicated that different LEDs and cytokinine specifically affected the growth and development of in vitro cultured pear plants. The highest fresh and dry mass distinguished the plants grown under white LED light with both cytokinines studied. The maximum values for plant height was achieved in plants grown under white LED light with BAP and blue LED light with mT. The leaf sizes of plants grown on mT enriched medium were larger than those grown on BAP enriched medium, regardless of light and the largest were the leaves of plants grown under white LED light. Also, plants grown with mT in the nutrient medium showed more intensive photosynthesis, with the difference between the white and mixed LED light being insignificant.
Ising model with stochastic resetting
Creators: name: Magoni, Matteo
name: Majumdar, Satya N.
name: Schehr, Gregory
Publisher: name: arXiv
Year: 2020
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We study the stationary properties of the Ising model that, while evolving towards its equilibrium state at temperature $T$ according to the Glauber dynamics, is stochastically reset to its fixed initial configuration with magnetisation $m_0$ at a constant rate $r$. Resetting breaks detailed balance and drives the system to a non-equilibrium stationary state where the magnetisation acquires a nontrivial distribution, leading to a rich phase diagram in the $(T,r)$ plane. We establish these results exactly in one-dimension and present scaling arguments supported by numerical simulations in two-dimensions. We show that resetting gives rise to a novel "pseudo-ferro" phase in the $(T,r)$ plane for $r > r^*(T)$ and $T>T_c$ where $r^*(T)$ is a crossover line separating the pseudo-ferro phase from a paramagnetic phase. This pseudo-ferro phase is characterised by a non-zero typical magnetisation and a vanishing gap near $m=0$ of the magnetisation distribution.
description: Main text: 5 pages + 2 Figures, Supp. Mat.: 7 pages + 5 Figures