cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Long-term Hard X-ray Monitoring of 2S 0114+65 with INTEGRAL/IBIS
Creators: name: Wang, Wei
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: (abridged) We present the results of the long-term hard X-ray monitoring of the high mass X-ray binary 2S 0114+65 with INTEGRAL/IBIS from 2003 to 2008. 2S 0114+65 is a variable hard X-ray source, when 2S 0114+65 was bright, we found a pulse period evolution of $\sim 2.67$ hour to 2.63 hour from 2003 -- 2008, with a spin-up rate of the neutron star $\sim 1.09\times 10^{-6}$ s s$^{-1}$. Compared with the previous reported spin-up rate, the spin-up rate of the neutron star in 2S 0114+65 is accelerating. The spectral properties of 2S 0114+65 in the band of 18 -- 100 keV which changed with the orbital phases. The variation of the power-law photon index over orbital phase anticorrelates with hard X-ray flux, and the variation of $E_{\rm cut}$ has a positive correlation with the hard X-ray flux, implying that the harder spectrum at the maximum of the light curve. The variations of spectral properties over orbital phase suggested 2S 0114+65 as a highly obscured binary system. In some observational revolutions, hard X-ray tails above 70 keV are detected. We study the characteristics of the hard X-ray tails combining JEM-X and IBIS data in the energy range of 3 -- 100 keV. The 3 -- 100 keV spectra of 2S 0114+65 are generally fitted by an absorbed power-law model with high energy cutoff. We discover that the hard X-ray tails are only detected when column density is very low. Thus, high column density leads to disappearance of the hard X-ray tails in this wind-fed neutron star accretion binary.
description: 17 pages, 15 figures, 6 tables, MNRAS in press
A Light QCD Axion with Hilltop Misalignment
Creators: name: Co, Raymond T.
name: Gherghetta, Tony
name: Liu, Zhen
name: Lyu, Kun-Feng
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study the cosmological evolution of a light QCD axion and identify the parameter space to obtain the correct relic dark matter abundance. The axion potential is flattened at the origin, corresponding to the only minimum, while it is unsuppressed at $π$. These potential features arise by assuming a mirror sector with the strong CP phase $\barθ$ shifted by $π$ compared to the SM sector, which allows the mirror axion potential to be tuned against the usual QCD axion potential. Before the QCD phase transition, assuming the mirror sector is decoupled and much colder than the SM thermal bath, the mirror sector potential dominates, causing the axion to initially roll to a temporary minimum at $π$. However, after the QCD phase transition, the potential minimum changes, and the axion relaxes from the newly created "hilltop" near $π$ to the CP-conserving minimum at the origin. As the axion adiabatically tracks this shift in the potential minimum through the QCD phase transition, with non-adiabatic evolution near $π$ and 0, it alters the usual prediction of the dark matter abundance. Consequently, this "hilltop" misalignment mechanism opens new regions of axion parameter space, with the correct relic abundance while still solving the strong CP problem, that could be explored in future experiments.
description: 28 pages, 9 figures. Match to the published version in JHEP
Low-cycle cyclic fatigue properties of novel nickel-titanium rotary endodontic instruments in the single- and double-curvatures.
Creators: name: Duke, Frédéric
Publisher: name: University of British Columbia
Year: 2015

description: Introduction: This in vitro study aimed to evaluate and compare the fatigue resistance of ProFile Vortex® (VX) and Vortex Blue® (VB) files in two different artificial double curvature canals (DC1 and DC2) and in an artificial single curvature canal (SC). The bending moment of VX and VB was assessed. Methods: The bending moment (g·cm) was used to measure flexibility of VX and VB (size 25/.04, length: 25mm) according to ISO 3630-1 specifications. Both files types were tested for cyclic fatigue failure inside canals containing: a single curvature (SC: 60⁰ curvature, 5 mm radius) and two canals with different double curvature (DC); [DC1: coronal curvature of 60⁰ and 5 mm radius, and apical curvature of 30⁰ and 2 mm radius; DC2: coronal curvature of 60⁰ and 5 mm radius, and apical curvature of 60⁰ and 2 mm radius]. The number of cycles to failure (NCF) was recorded and the fracture surface of all fragments was examined with a scanning electron microscope (SEM) to confirm cyclic fatigue failure and for qualitative analysis of pattern of fracture. Results: VX and VB followed slightly different trajectories in the identical canals, especially in double curvature canals. The mean bending moment value was significantly lower for VB than for VX (p < .001). NCF for the two files were significantly higher in the single curvature canal (SC) compared to the two double curvature canals (DC1 and DC2) (p < .001). Of the double curvature canals, the NCF was significant higher in DC1 than in DC2 for VB (p < .05) but not for VX (p > .05). In the SC group, VB had NCF superior to VX (p < .05). In DC1 and DC2 groups, NCF of VX and VB was not statistically different from each other (p > .05). Multiple crack origins were observed for the majority of files fractured in DC1 and DC2 canals. Conclusions: DC1 and DC2 canals demonstrated a more stressful and challenging anatomy than the SC canal for VX and VB. In double curvature canals, degree of curvature and radius, and the file’s flexibility may affect the mean NCF.
Study of the $DK$ interaction with femtoscopic correlation functions
Creators: name: Liu, Zhi-Wei
name: Lu, Jun-Xu
name: Geng, Li-Sheng
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The $DK$ interaction in isospin zero is known to be attractive to such an extent that a bound state can be generated, which can be associated with the mysterious $D_{s0}^*(2317)$. In this work, we calculate the $DK$ femtoscopic correlation function in the coupled-channel framework for different source sizes that can directly probe the strongly attractive $DK$ interaction, which is otherwise inaccessible due to the unstable nature of $D$ and $K$ mesons, and therefore can help elucidate the nature of $D_{s0}^*(2317)$. We further generalize the study of source size dependence to various interactions, ranging from repulsive, weakly attractive, moderately attractive, and strongly attractive, in a square-well model. We hope that our study can motivate future experimental measurements of the $DK$ correlation function and other interactions relevant to the understanding of the nature of the many exotic hadrons discovered so far.
description: 8 pages, 3 figures; clarifications added and discussions refined, to appear in Physical Review D
Studying the Multi-frequency Angular Power Spectrum of the Cosmic Dawn 21-cm Signal
Creators: name: Shaw, Abinash Kumar
name: Ghara, Raghunath
name: Zaroubi, Saleem
name: Mondal, Rajesh
name: Mellema, Garrelt
name: Mertens, Florent
name: Koopmans, Léon V. E.
name: Semelin, Benoît
Publisher: name: arXiv
Year: 2023
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: The light-cone (LC) anisotropy arises due to cosmic evolution of the cosmic dawn 21-cm signal along the line-of-sight (LoS) axis of the observation volume. The LC effect makes the signal statistically non-ergodic along the LoS axis. The multi-frequency angular power spectrum (MAPS) provides an unbiased alternative to the popular 3D power spectrum as it does not assume statistical ergodicity along every direction in the signal volume. Unlike the 3D power spectrum which mixes the cosmic evolution of the 21-cm signal along the LoS $k$ modes, MAPS keeps the evolution information disentangled. Here we first study the impact of different underlying physical processes during cosmic dawn on the behaviour of the 21-cm MAPS using simulations of various different scenarios and models. We also make error predictions in 21-cm MAPS measurements considering only the system noise and cosmic variance for mock observations of HERA, NenuFAR and SKA-Low. We find that $100~{\rm h}$ of HERA observations will be able to measure 21-cm MAPS at $\geq 3σ$ for $\ell \lesssim 1000$ with $0.1\,{\rm MHz}$ channel-width. The better sensitivity of SKA-Low allows reaching this sensitivity up to $\ell \lesssim 3000$. Note that due to the difference in the frequency coverage of the various experiements, the CD-EoR model considered for NenuFAR is different than those used for the HERA and SKA-Low predictions. Considering NenuFAR with the new model, measurements $\geq 2σ$ are possible only for $\ell \lesssim 600$ with $0.2\,{\rm MHz}$ channel-width and for a ten times longer observation time of $t_{\rm obs} = 1000~{\rm h}$. However, for the range $300 \lesssim \ell \lesssim 600$ and $t_{\rm obs}=1000~{\rm h}$ more than $3σ$ measurements are still possible for NenuFAR when combining consecutive frequency channels within a $5 ~{\rm MHz}$ band.
description: 21 pages, 12 figures, 3 tables, accepted for publication in MNRAS
Top-down fabrication of bulk-insulating topological insulator nanowires for quantum devices
Creators: name: Rößler, Matthias
name: Fan, Dingxun
name: Münning, Felix
name: Legg, Henry F.
name: Bliesener, Andrea
name: Lippertz, Gertjan
name: Uday, Anjana
name: Yazdanpanah, Roozbeh
name: Feng, Junya
name: Taskin, Alexey A.
name: Ando, Yoichi
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: In a nanowire (NW) of a three-dimensional topological insulator (TI), the quantum-confinement of topological surface states leads to a peculiar subband structure that is useful for generating Majorana bound states. Top-down fabrication of TINWs from a high-quality thin film would be a scalable technology with great design flexibility, but there has been no report on top-down-fabricated TINWs where the chemical potential can be tuned to the charge neutrality point (CNP). Here we present a top-down fabrication process for bulk-insulating TINWs etched from high-quality (Bi$_{1-x}$Sb$_{x}$)$_2$Te$_3$ thin films without degradation. We show that the chemical potential can be gate-tuned to the CNP and the resistance of the NW presents characteristic oscillations as functions of the gate voltage and the parallel magnetic field, manifesting the TI-subband physics. We further demonstrate the superconducting proximity effect in these TINWs, preparing the groundwork for future devices to investigate Majorana bound states.
description: 32 pages. 22 main text, 10 SI
Discussion of "Statistical Inference: The Big Picture" by R. E. Kass
Creators: name: McCulloch, Robert
Publisher: name: arXiv
Year: 2011
Subjects: subject: Methodology (stat.ME)
subject: FOS: Computer and information sciences

description: Discussion of "Statistical Inference: The Big Picture" by R. E. Kass [arXiv:1106.2895]
description: Published in at http://dx.doi.org/10.1214/11-STS337D the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Charge Orbits of Extremal Black Holes in Five Dimensional Supergravity
Creators: name: Cerchiai, Bianca L.
name: Ferrara, Sergio
name: Marrani, Alessio
name: Zumino, Bruno
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We derive the U-duality charge orbits, as well as the related moduli spaces, of "large" and "small" extremal black holes in non-maximal ungauged Maxwell-Einstein supergravities with symmetric scalar manifolds in d=5 space-time dimensions. The stabilizer groups of the various classes of orbits are obtained by determining and solving suitable U-invariant sets of constraints, both in "bare" and "dressed" charges bases, with various methods. After a general treatment of attractors in real special geometry (also considering non-symmetric cases), the N=2 "magic" theories, as well as the N=2 Jordan symmetric sequence, are analyzed in detail. Finally, the half-maximal (N=4) matter-coupled supergravity is also studied in this context.
description: 1+63 pages, 6 Tables
PROPERTIES OF MATERIALS USED IN ORTHOPAEDIC FIXATION
Creators: name: Ramachandran, Reshma Neena
name: Dudko Oleksii Gennadiyovich
name: Shayko-Shaykovskiy Oleksandr Gennadiyovich
Publisher: name: Colloquium-journal
Year: 2020
Subjects: bone fractures
orthopaedic devices
materials
biomechanics.

description: As the number of injuries of the locomotor system is continuously increasing, the research in the field of orthopaedic devices can improve the outcome of treatment of such the most common and severe injuries as bone fractures. In the paper the authors describe main parameters of materials and orthopaedics devices that are used for their manufacturing. The main requirements are highlighted, as high biocompatibility, low toxici-ty, high mechanical properties that are essentially important for proper fixation of fracture fragments. As new demands for materials arise, such properties as biodegradation and self-resolving abilities are preferable, so different types of these materials were analysed in the paper.
Operators on compositions and noncommutative Schur functions
Creators: name: Tewari, Vasu
Publisher: name: University of British Columbia
Year: 2015

description: In this thesis, we study a natural noncommutative lift of the ubiquitous Schur functions, called noncommutative Schur functions. These functions were introduced by Bessenrodt, Luoto and van Willigenburg and resemble Schur functions in many regards. We prove some new results for noncommutative Schur functions that are analogues of classical results, and demonstrate that the resulting combinatorics in this setting is equally rich. First we prove a Murnaghan-Nakayama rule for noncommutative Schur functions. In other words, we give an explicit combinatorial formula for expanding the product of a noncommutative power sum symmetric function and a noncommutative Schur function in terms of noncommutative Schur functions. In direct analogy to the classical Murnaghan-Nakayama rule, the summands are computed using a noncommutative analogue of border strips, and have coefficients ±1 determined by the height of these border strips. The rule is proved by interpreting the noncommutative Pieri rules for noncommutative Schur functions in terms of box adding operators on compositions. We proceed to give a backward jeu de taquin slide analogue on semistandard reverse composition tableaux. These tableaux were first studied by Haglund, Luoto, Mason and van Willigenburg when defining quasisymmetric Schur functions. Our algorithm for performing backward jeu de taquin slides on semistandard reverse composition tableaux results in a natural operator on compositions that we call the jdt operator. This operator in turn gives rise to a new poset structure on compositions whose maximal chains we enumerate. As an application, we also give new right Pieri rules for noncommutative Schur functions that use the jdt operators, in contrast to the left Pieri rules given by Bessenrodt, Luoto and van Willigenburg.
Frustration in a dipolar Bose-Einstein condensate introduced by an optical lattice
Creators: name: Halperin, Eli J.
name: Ronen, Shai
name: Bohn, J. L.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: We study the application of a square perturbing lattice to the naturally forming hexagonal arrays of dipolar droplets in a dipolar Bose-Einstein condensate. We find that the application of the lattice causes spontaneous pattern formation and leads to frustration in some regimes. For certain parameters, the ground state has neither the symmetry of the intrinsic hexagonal supersolid nor the symmetry of the square lattice. These results may give another axis on which to explore dipolar Bose-Einstein condensates and to probe the nature of supersolidity.
The Euclidean Adler Function and its Interplay with $Δα^{\mathrm{had}}_{\mathrm{QED}}$ and $α_s$
Creators: name: Davier, M.
name: Díaz-Calderón, D.
name: Malaescu, B.
name: Pich, A.
name: Rodríguez-Sánchez, A.
name: Zhang, Z.
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: Three different approaches to precisely describe the Adler function in the Euclidean regime at around $2\, \mathrm{GeVs}$ are available: dispersion relations based on the hadronic production data in $e^+e^-$ annihilation, lattice simulations and perturbative QCD (pQCD). We make a comprehensive study of the perturbative approach, supplemented with the leading power corrections in the operator product expansion. All known contributions are included, with a careful assessment of uncertainties. The pQCD predictions are compared with the Adler functions extracted from $Δα^{\mathrm{had}}_{\mathrm{QED}}(Q^2)$, using both the DHMZ compilation of $e^+e^-$ data and published lattice results. Taking as input the FLAG value of $α_s$, the pQCD Adler function turns out to be in good agreement with the lattice data, while the dispersive results lie systematically below them. Finally, we explore the sensitivity to $α_s$ of the direct comparison between the data-driven, lattice and QCD Euclidean Adler functions. The precision with which the renormalisation group equation can be tested is also evaluated.
description: 56 pages, 22 figures, 14 tables. Published version
Black holes as generalised Toda molecules
Creators: name: Chemissany, Wissam
name: Rosseel, Jan
name: Van Riet, Thomas
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: FOS: Physical sciences

description: In this note we compare the geodesic formalism for spherically symmetric black hole solutions with the black hole effective potential approach. The geodesic formalism is beneficial for symmetric supergravity theories since the symmetries of the larger target space leads to a complete set of commuting constants of motion that establish the integrability of the geodesic equations of motion, as shown in arXiv:1007.3209. We point out that the integrability lifts straightforwardly to the integrability of the equations of motion with a black hole potential. This construction turns out to be a generalisation of the connection between Toda molecule equations and geodesic motion on symmetric spaces known in the mathematics literature. We describe in some detail how this generalisation of the Toda molecule equations arises.
description: 19 pages, references added
Generation of modified DNA aptamers toward a complex whole cell target and investigations into improving selection methodology with modified DNA
Creators: name: Miller, Emily W.
Publisher: name: University of British Columbia
Year: 2015

description: Since the discovery was made that DNA is capable of functions beyond genetic storage and propagation, much work has been done to explore the non-canonical abilities of this molecule. Two functionalities of DNA are of particular interest. The first is the ability of DNA to act as a catalyst, and the second is the ability of the molecule to bind with high affinity to various biological and non-biological surfaces. Although numerous DNA catalysts and binders (termed “aptamers”) have been identified using the five nucleoside triphosphates found in nature, the functionality of the molecule can be expanded with the addition of protein-like functional groups to the base moiety of the nucleotide. Several modified nucleotides have been developed previously and used to discover novel catalysts and aptamers. However, the successful development of modified-DNA aptamers has thus far been limited, particularly with respect to biological targets that might be of use in a clinical or commercial context. Moreover, technical challenges in the field exist that have not yet been adequately addressed. Most significantly, the employment of the modified molecules in the discovery process can be problematic as they are not ideal substrates for many basic molecular biology procedures, notably polymerase chain reaction. New techniques to overcome these difficulties are needed and few have been developed. This thesis will focus on two aspects of modified DNA research. The first is the application of modified DNA in aptamer discovery. Starting from the hypothesis that additional functional groups will confer chemical advantages in traditionally challenging aptamer selections, the objective was to identify a modified DNA aptamer for whole bacterial cells in vitro. Several promising phenol-dUTP-modified aptamer sequences were identified using a modified SELEX procedure. The specificity and affinity of these sequences for the target bacterial strain were investigated. The second aim of this work is to address technical problems encountered when working with modified DNA in order to develop catalysts or aptamers. Specifically, a novel selection scheme was designed that eliminated the need to amplify modified DNA. Research was conducted to develop and validate this selection system as a viable route to discovery of DNA catalysts.
Towards Quantum Sensing of Chiral-Induced Spin Selectivity: Probing Donor-Bridge-Acceptor Molecules with NV Centers in Diamond
Creators: name: Völker, Laura A.
name: Herb, Konstantin
name: Janitz, Erika
name: Degen, Christian L.
name: Abendroth, John M.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Biological Physics (physics.bio-ph)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: Photoexcitable donor-bridge-acceptor (D-B-A) molecules that support intramolecular charge transfer are ideal platforms to probe the influence of chiral-induced spin selectivity (CISS) in electron transfer and resulting radical pairs. In particular, the extent to which CISS influences spin polarization or spin coherence in the initial state of spin-correlated radical pairs following charge transfer through a chiral bridge remains an open question. Here, we introduce a quantum sensing scheme to measure directly the hypothesized spin polarization in radical pairs using shallow nitrogen-vacancy (NV) centers in diamond at the single- to few-molecule level. Importantly, we highlight the perturbative nature of the electron spin-spin dipolar coupling within the radical pair, and demonstrate how Lee-Goldburg decoupling can preserve spin polarization in D-B-A molecules for enantioselective detection by a single NV center. The proposed measurements will provide fresh insight into spin selectivity in electron transfer reactions.
description: 7 pages and 4 pages appendix including an extensive description of the initial spin state of photo-generated radical pairs
Orbital Evolution of Binaries in Circumbinary Disks
Creators: name: Siwek, Magdalena
name: Weinberger, Rainer
name: Hernquist, Lars
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present the to-date largest parameter space exploration of binaries in circumbinary disks (CBDs), deriving orbital evolution prescriptions for eccentric, unequal mass binaries from our suite of hydrodynamic simulations. In all cases, binary eccentricities evolve towards steady state values that increase with mass ratio, and saturate at an equilibrium eccentricity $e_{\rm b, eq} \sim 0.5$ in the large mass ratio regime, in line with resonant theory. For binaries accreting at their combined Eddington limit, a steady state eccentricity can be achieved within a few Megayears. Once at their steady state eccentricities, binaries with $q_{\rm b} \gtrsim 0.3$ evolve towards coalescence, while lower mass ratio systems expand due to CBD torques. We discuss implications for population studies of massive black hole binaries, protostars in binary systems, and post-common envelope binaries observed by ground-based gravitational wave detectors.
description: 12 pages, 8 figures. Submitted to MNRAS
Carleman estimates for elliptic operators with jumps at an interface: Anisotropic case and sharp geometric conditions
Creators: name: Rousseau, Jérôme Le
name: Lerner, Nicolas
Publisher: name: arXiv
Year: 2010
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35J15, 35J57, 35J75

description: We consider a second-order selfadjoint elliptic operator with an anisotropic diffusion matrix having a jump across a smooth hypersurface. We prove the existence of a weight-function such that a Carleman estimate holds true. We moreover prove that the conditions imposed on the weight function are necessary.
description: 43 pages
The experience of mothers and clinicians in the assessment of autism spectrum disorder
Creators: name: Bowers, Anna
Publisher: name: University of British Columbia
Year: 2015

description: Being told that their child meets criteria for a diagnosis of Autism Spectrum Disorder (ASD) is life-changing news for parents. Prior to the diagnosis, they wait and worry and are faced with uncertainty about their child. After receiving the diagnosis, parents must adjust to the loss of “normalcy” and the demands of arranging services. In Canada, psychologists are regularly involved in conducting assessments and communicating the diagnosis of ASD to parents. Despite research examining parents’ experience with the diagnostic process, few studies have additionally considered clinicians’ perspectives and practices in conducting ASD assessments. In the present study, the experiences of mothers and clinicians before, during, and after a diagnosis of ASD were examined. The aim was to better understand how parents present when coming to an assessment for ASD, their reaction to the diagnosis, and the support they and their child received. This had the potential to provide insight into effective ways to meet the needs of parents as they process and attempt to move forward with their child’s diagnosis of ASD. In the present study, semi-structured interviews were conducted with mothers and clinicians from lower mainland British Columbia. Data was categorized and analyzed using an inductive approach to thematic analysis. From the mother interviews, twelve themes emerged to depict experiences across the phases of assessment, while fourteen themes were revealed through clinician interviews. Findings revealed that mothers suspected ASD before the assessment began, clinicians made attempts to be clear and compassionate, and that information regarding resources was sufficient yet overwhelming for parents. In general, mothers were satisfied with the clinician and assessment approach yet discontent with the understanding and support received from outside sources.
Fast Vacuum Decay into Quark Pairs in Strong Color Electric and Magnetic Fields
Creators: name: Hidaka, Yoshimasa
name: Iritani, Takumi
name: Suganuma, Hideo
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study quark-pair creations in strong color electromagnetic fields. We point out that, for massless quarks, the vacuum persistency probability per unit space-time volume is zero, i.e., the quark-pair creation rate w is infinite, in general homogeneous color electromagnetic fields, while it is finite when the color magnetic field is absent. We find that the contribution from the lowest Landau level (LLL) dominates this phenomenon. With an effective theory of the LLL projection, we also discuss dynamics of the vacuum decay, taking into account the back reaction of pair creations.
description: 4 pages, 1 figure, contribution to the proceedings of International conference on the structure of baryons (BARYONS'10), RCNP, Osaka, Japan, Dec. 7-11, 2010; fig.2 deleted
The basis of belief : the cognitive and cultural foundations of supernatural belief
Creators: name: Willard, Aiyana K.
Publisher: name: University of British Columbia
Year: 2015

description: In this dissertation I explore the relative roles of cognition and culture play as the foundations of religious and supernatural belief. On the cognitive side, theories of religion have postulated several cognitive biases that predispose human minds towards supernatural belief. However, to this date, very little empirical evidence exists to show how these hypotheses preform in predicting actual religious beliefs. I explore these biases and how they interrelate to support supernatural beliefs using individual difference measures across several large samples from Canada, the US, the Czech Republic and Slovakia. On the cultural side, I look at how different theories of secularization and the CREDs theory of cultural learning support supernatural belief and religious practice. I compare these effects of culture to the effects of cognition and find that cognitive biases support supernatural belief generally, but these effects are stronger for paranormal beliefs than religious ones and are almost non-existence for religious practice. Religious belief and practice are largely supported by social and cultural factors. Finally, I compare religious and non-religious participants to spiritual but not religious (SBNR) participants to further break down the differences between religious and non-religious supernatural beliefs and religious practice. I find that the SBNR are more like the religious than the non-religious but can still be identified as a unique group in terms of cognition and culture.
Black hole event horizons are cosmologically coupled
Creators: name: Faraoni, Valerio
name: Rinaldi, Massimiliano
Publisher: name: arXiv
Year: 2024
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: It is shown that an exactly static and spherically symmetric black hole event horizon cannot be embedded in a time-dependent geometry. Forcing it to do so results in a naked null singularity at the would-be horizon. Therefore, since the universe is expanding, black holes must couple to the cosmological expansion, which was suggested as the growth mechanism for supermassive black holes in galaxies, with implications for the dark energy puzzle.
description: To appear in Physical Review D
UNIVERSIDADE_FEDERAL_DA_PARAIBA_assinado_assinado(1).pdf
Creators: name: Souza, Joseane
Publisher: name: figshare
Year: 2021
Subjects: subject: 80706 Librarianship
subject: FOS: Media and communications

description: Trabalho realizado na disciplina de tecnologia da informação do curso de arquivologia, na Universidade Federal da Paraíba. O tema do trabalho é assinatura digital realizada no site: gov.br e no assinador.iti.br.
Statistical proerties of the two-dimensional Feshbach-illars oscillator (FVO) in the rotating cosmic string
Creators: name: Bouzenada, Abdelmalek
name: Boumali, Abdelmalek
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: This paper is concerned with an investigation of the quantum mechanical dynamics of massive, spinless relativistic Klein-Gordon particle in the space-time generated by a rotating cosmic string. The equations of motion are found by the use of the first-order Feshbach-Villars formulation of the Klein-Gordon equation. The wave-functions and the associated energies were deduced ( both in the free and in the interaction case). Following that, the partition function was approximated using Zeta function representation. Moreover, by considering the energy spectrum of the system in question, the thermal properties are presented. We examine the behavior of these properties as a function of the physical parameters of the model such as rotation, curvature, and quantum numbers. Therefore, the impact of the topological defect on the quantum system under investigation is discussed.
The climatology and meteorology of windstorms that affect southwest British Columbia, Canada, and associated tree-related damage to the power distribution grid
Creators: name: Read, Wolf Anthony
Publisher: name: University of British Columbia
Year: 2015

description: High-wind generating extratropical cyclones routinely strike southwest British Columbia. Improved understanding of these storms could help mitigate damage to electrical and other infrastructure. All independent windstorms from 1964-2012 were determined using the Victoria, Vancouver and Abbotsford hourly surface observations. For all qualifying events 1994-2012, storm tracks and central pressure tendencies were determined using surface maps. Storms were classified by peak wind direction and track location. Detailed synoptic and mesoscale maps were made and analyzed for eight strong windstorms. BC Hydro Corporation distribution-system power outage data from October 2005 to August 2009 was used in an analysis of tree-related line faults within a 50 km radius of Vancouver. For events with peak speed >40 km h-¹, maximum wind, gust, wind direction, storm total precipitation and storm duration were used to predict line faults using linear and Poisson regression. Data from four strong windstorms was used in an hour-by-hour analysis of wind speed and line faults. There were two dominant categories of cyclonic windstorm in this region: westerly and southeasterly. Cyclone tracks had much variation. However, compared to westerly storms, southeasters tended to have a stronger northward component to their direction of motion and tended to pass closer to the study region. Most low-pressure centers weakened rapidly as they moved inland and, as a result, peak winds typically occurred at landfall. The exception is for westerly storms where the wind is dependent on an onshore pressure gradient behind the low. There was moderately strong linear relationship between peak two-min wind or five-s gust and the frequency of distribution line faults. Poisson regression models indicate the potential for widespread grid damage for wind speeds approaching the historic 12 Oct 1962 windstorm. On average, southeasters cause approximately 1.5-1.9 times more line faults than westerly windstorms. A few-hour lag in the occurrence of line faults relative to observed wind speed, perhaps due to reporting delays, was observed. This has not been reported before and could confound analyses that use daily data. The modeling done here could be expanded to forecast storm impacts to the power grid using numerical weather prediction model inputs.
Unpolarized generalized parton distributions of light and heavy vector mesons
Creators: name: Shi, Chao
name: Li, Jicheng
name: Yin, Pei-Lin
name: Jia, Wenbao
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study the leading-twist unpolarized generalized parton distributions (GPDs) of light and heavy vector mesons, i.e., the $ρ$, $J/ψ$ and $Υ$, at zero skewness. An ansatz incorporating the zero mode contribution is introduced to modify the light front overlap representation of GPDs. The leading Fock-state light front wave functions (LF-LFWFs) of vector mesons from DS-BSEs approach are then employed to study the meson GPDs. The light front spatial distribution of valence quarks within vector mesons is then studied with the impact parameter dependent GPD (IPD GPD). We also investigate the electromagnetic and gravitational form factors, which are the first and second Mellin moments of the GPDs. The light-cone mass radius of $ρ$ is determined to be 0.30 fm, close to a recent NJL model prediction 0.32fm. For $J/ψ$ and $Υ$, they are predicted to be 0.151fm and 0.089 fm respectively.
description: 9 pages, 9 figures
How does galaxy environment matter? The relationship between galaxy environments, colour and stellar mass at 0.4 < z < 1 in the Palomar/DEEP2 survey
Creators: name: Grützbauch, Ruth
name: Conselice, Christopher J.
name: Varela, Jesús
name: Bundy, Kevin
name: Cooper, Michael C.
name: Skibba, Ramin
name: Willmer, Christopher N. A.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We present a study characterizing the environments of galaxies in the redshift range of 0.4 < z < 1 based on data from the POWIR near infrared imaging and DEEP2 spectroscopic redshift surveys, down to a stellar mass of log M* = 10.25 M_sun. Galaxy environments are measured in terms of nearest neighbour densities as well as fixed aperture densities and kinematical and dynamical parameters of neighbour galaxies within a radius of 1 Mpc. We disentangle the correlations between galaxy stellar mass, galaxy colour and galaxy environment, using not only galaxy number densities, but also other environmental characteristics such as velocity dispersion, mean harmonic radius, and crossing time. We find that galaxy colour and the fraction of blue galaxies depends very strongly on stellar mass at 0.4 < z < 1, while a weak additional dependence on local number densities is in place at lower redshifts (0.4 < z < 0.7). This environmental influence is most visible in the colours of intermediate mass galaxies (10.5 < log M* < 11), whereas colours of lower and higher mass galaxies remain largely unchanged with redshift and environment. At a fixed stellar mass, the colour-density relation almost disappears, while the colour-stellar mass relation is present at all local densities. We find a weak correlation between stellar mass and environment at intermediate redshifts, which contributes to the overall colour-density relation. We furthermore do not find a significant correlation between galaxy colour and virial mass, i.e., parent dark matter halo mass. Galaxy stellar mass thus appears to be the crucial defining parameter for intrinsic galaxy properties such as ongoing star formation and colour.
description: 20 pages, 13 figures, accepted for publication in MNRAS
Improved quasiparticle self-consistent electronic band structure and excitons in $β$-LiGaO$_2$
Creators: name: Dadkhah, Niloufar
name: Lambrecht, Walter R. L.
name: Pashov, Dimitar
name: van Schilfgaarde, Mark
Publisher: name: arXiv
Year: 2023
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The band structure of $β$-LiGaO$_2$ is calculated using the quasiparticle self-consistent QS$G\hat W$ method where the screened Coulomb interaction $\hat W$ is evaluated including electron-hole interaction ladder diagrams and $G$ is the one-electron Green's function. Improved convergence compared to previous calculations leads to a significantly larger band gap of about 7.0 eV. However, exciton binding energies are found to be large and lead to an exciton gap of about 6.0 eV if also a zero-point-motion correction of about $-0.4$ eV is included. These results are in excellent agreement with recent experimental results on the onset of absorption. Besides the excitons observed thus far, the calculations indicate the existence of a Rydberg-like series of exciton excited states, which is however modified from the classical Wannier exciton model by the anisotropies of the material and the more complex mixing of Bloch states in the excitons resulting from the Bethe-Salpeter equation. The exciton fine structure and the exciton wave functions are visualized and analyzed in various ways.
Uranous sulfate precipitation as a novel route to uranium purification in extractive metallurgy
Creators: name: Burns, Alexander D.
Publisher: name: University of British Columbia
Year: 2015

description: Uranous sulfate can be crystallized from uranium(IV)-containing solutions by raising the temperature and adding sulfuric acid. Several important aspects of the process have never been investigated, however, making its successful application as a real-world extractive metallurgy technology far from certain. This dissertation addresses several fundamental questions surrounding the crystallization of uranous sulfate from acidic process solutions. The effects of various parameters on the solubility of uranous sulfate and the kinetics of its precipitation are demonstrated, including temperature, acid concentration, and agitation, based on the results from a series of bench-scale experiments. The effects of various impurities on the selectivity and efficiency of the crystallization process are also determined. Two new uranous sulfate x-hydrate polymorphs, the hexahydrate and the octahydrate, are characterized using single-crystal x-ray diffraction, vibrational spectroscopy, and chemical assay data, and an understanding of the conditions under which they form is developed. The thermal stability and decomposition characteristics of uranous sulfate tetrahydrate, hexahydrate, and octahydrate are demonstrated through fundamental thermodynamic calculations and through the examination of thermal analysis data. The fundamental kinetics of uranium(IV) oxidation in acidic solutions are quantified through the interpretation of experimental data under various conditions of acidity, temperature, and oxygen partial pressure. Finally, a hydrometallurgy flow sheet incorporating uranous sulfate precipitation is presented, and the viability of the complete process is demonstrated experimentally, including electrolytic reduction, precipitation, filtration, drying, and calcining. This work demonstrates that uranous sulfate precipitation is viable as a hydrometallurgical process technology, and that further work is justified.
The Radiative Efficiency of Accretion Flows in Individual AGN
Creators: name: Davis, Shane W.
name: Laor, Ari
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The radiative efficiency of AGN is commonly estimated based on the total mass accreted and the total AGN light emitted per unit volume in the universe integrated over time (the Soltan argument). In individual AGN, thin accretion disk model spectral fits can be used to deduce the absolute accretion rate Mdot, if the black hole mass M is known. The radiative efficiency η is then set by the ratio of the bolometric luminosity L_bol to Mdot c^2. We apply this method to determine η in a sample of 80 PG quasars with well determined L_bol, where Mdot is set by thin accretion disk model fits to the optical luminosity density, and the M determination based on the bulge stellar velocity dispersion (13 objects) or the broad line region (BLR). For the BLR-based masses, we derive a mean log η = -1.05 +/- 0.52 consistent with the Soltan argument based estimates. We find a strong correlation of η with M, rising from η ~ 0.03 at M = 10^7 M{\odot} and L/L_Edd ~ 1 to η ~ 0.4 at M = 10^9 M{\odot} and L/L_Edd ~ 0.3. This trend is related to the overall uniformity of L_opt/L_bol in our sample, particularly the lack of the expected increase in L_opt/L_bol with increasing M (and decreasing L/L_Edd), which is a generic property of thermal disk emission at fixed η. The significant uncertainty in the M determination is not large enough to remove the correlation. The rising η with M may imply a rise in the black hole spin with M, as proposed based on other indirect arguments.
description: 20 pages, accepted for publication in The Astrophysical Journal
Potential for potassium recovery as K-struvite
Creators: name: Bennett, Aline Miriam
Publisher: name: University of British Columbia
Year: 2016

description: Crystallization of NH₄-struvite (MgNH₄PO4:6H₂O) pellets has proven to be a successful method of recovering nitrogen and phosphorus from wastewaters. Thus far, little work has been done on potassium recovery since it is not considered a water pollutant, nor do we face potassium shortages. However, potassium is an essential plant macronutrient and we are seeing worldwide imbalances in nutrient and fertilizer use, as well as a need for a slow release potassium fertilizer. Development of a full complement NPK fertilizer with NH₄-struvite and K-struvite components may have great potential. Given this, research into potassium recovery through crystallization of K-struvite (MgKPO₄: 6H₂O) is relevant and complements previous work done with NH₄-struvite. The goals of this research were to develop fundamental understanding of K-struvite formation as the first step to recovering potassium, and eventually produce a full complement NPK slow-release fertilizer from wastewaters. This required the determination of new solubility product values for K-struvite at different temperatures, followed by bench-scale experiments to assess K-struvite synthesis under various solution conditions. A model to simulate each batch experiment and to predict optimal supersaturation conditions for K-struvite precipitation was developed using PHREEQC, aqueous equilibrium modelling software. Finally, initial experiments in the UBC fluidized bed reactor (UBC-FBR) were undertaken to assess the pelletization potential of K-struvite. New solubility product values for K-struvite indicate that it is less soluble than previously reported, and the values determined at 10, 25 and 35°C fit the Van’t Hoff model. Optimal Mg:K:P molar ratio for synthesis of pure K-struvite was found to be approximately 3:50:1 in a wastewater matrix with pH 8, P-PO₄ concentration of 8 mM and a Mg:P ratio of 3:1. These concentrations were used in the UBC-FBR to assess the pelletization potential of K-struvite. These initial reactor runs were inconclusive due to an inability to stabilize the reactor without seeding. It would be recommended to seed the reactor during start-up in order to be able to compare process performance with the NH₄-struvite crystallization process in the UBC-FBR. This study showed that formation of pure K-struvite is possible given the right supersaturation conditions in solution, requiring high potassium concentrations.