cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Rejection sensitivity in early adolescence
Creators: name: Tsirgielis, Constantina
Publisher: name: University of British Columbia
Year: 2015

description: Repeated rejection experiences may encourage a hypersensitivity to rejection stimuli and cues, defined as rejection sensitivity (RS): a dispositional pattern of responding in relationships with defensive expectations of rejection (Downey et al., 1998). Rejection sensitive youth perceive signs of rejection in situations others would consider neutral or ambiguous. Hypersensitivity to social rejection increases anxiety in social interactions where rejection is possible and leads to withdrawal, feelings of loneliness, social anxiety (SA), and depression. RS therefore can be considered a mechanism to explain the development of internalizing disorders such as SA. SA youth are also hypersensitive to cues of rejection, and tend to withdraw from their peer groups to avoid possible rejection, which leads to loneliness, depression, interpersonal problems, and increased SA (Sameroff & MacKenzie, 2003). Previous research reviewed the impact of RS on youth’s social and emotional wellbeing and have identified SA as a potential outcome of RS (Bowker et al., 2011, Marston et al., 2010, McDonald et al., 2010). There is limited research investigating the bidirectional relationship between RS-Anxiety and SA. Self-report data from grade 6 and 7 students (n=128) at a large, urban school district were collected. The goal of this research study was to 1) identify the relationship between RS-anxiety and SA, 2) determine if there are gender differences on the RS-Anxiety, and SA measures 3) investigate whether emotional symptoms influenced the relationship between RS-Anxiety and SA and 3) determine whether RS-Anxiety and SA predict peer problems in youth. Analyses performed include a bivariate correlational analysis, two-tailed independent samples t-test, a mediation analysis, and a hierarchical multiple regression. Results from the analyses revealed that there is a positive correlation between RS-Anxiety and SA, and emotional symptoms significantly mediated that relationship. SA also significantly predicted peer problems in RS-Anxious youth. However, no gender difference was found on the SA or RS-Anxiety measures.
Norm preserving stochastic field equation for an ideal Bose gas in a trap: numerical implementation and applications
Creators: name: Heller, S.
name: Strunz, W. T.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: Stochastic field equations represent a powerful tool to describe the thermal state of a trapped Bose gas. Often, such approaches are confronted with the old problem of an ultraviolet catastrophe, which demands a cutoff at high energies. In [arXiv:0809.1002, Phys. B 42, 081001 (2009)] we introduce a quantum stochastic field equation, avoiding the cutoff problem through a fully quantum approach based on the Glauber-Sudarshan P-function. For a close link to actual experimental setups the theory is formulated for a fixed particle number and thus based on the canonical ensemble. In this work the derivation and the non-trivial numerical implementation of the equation is explained in detail. We present applications for finite Bose gases trapped in a variety of potentials and show results for ground state occupation numbers and their equilibrium fluctuations. Moreover, we investigate spatial coherence properties by studying correlation functions of various orders.
description: 11 pages, 6 figures
Transport properties of the single- and 3-core Fe-Se wires fabricated by a novel chemical-transformation PIT process
Creators: name: Mizuguchi, Yoshikazu
name: Izawa, Hiroki
name: Ozaki, Toshinori
name: Takano, Yoshihiko
name: Miura, Osuke
Publisher: name: arXiv
Year: 2011
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We fabricated single- and 3-core superconducting Fe-Se wires using a novel process based on a chemical transformation from hexagonal FeSe1+d (non-superconducting) to tetragonal FeSe (superconducting) via an optimal supply of Fe from the Fe sheath by annealing. This process enhanced a packing density of superconducting core inside the sheath, owing to an expansion of the lattice volume via a chemical transformation from high-density hexagonal FeSe1+d to low-density tetragonal FeSe. The obtained superconducting wire showed superconductivity below ~10 K and the upper critical field was estimated to be 19.3 T at 0 K. The obtained transport critical current densities at 0 T were 588 A/cm2 for the 3-core wire and 218 A/cm2 for the single-core wire.
description: 17 pages, 4 figures
Supercurrent and Electromotive force generations by the Berry connection from many-body wave functions
Creators: name: Koizumi, Hiroyasu
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: Superconductivity (cond-mat.supr-con)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: The velocity field composed of the electromagnetic field vector potential and the Berry connection from many-body wave functions explains supercurrent generation, Faraday's law for the electromotive force (EMF) generation, and other EMF generations whose origins are not electromagnetism. An example calculation for the EMF from the Berry connection is performed using a model for the cuprate superconductivity.
Ultra-high neutrino fluxes as a probe for non-standard physics
Creators: name: Bhattacharya, Atri
name: Choubey, Sandhya
name: Gandhi, Raj
name: Watanabe, Atsushi
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We examine how light neutrinos coming from distant active galactic nuclei (AGN) and similar high energy sources may be used as tools to probe non-standard physics. In particular we discuss how studying the energy spectra of each neutrino flavour coming from such distant sources and their distortion relative to each other may serve as pointers to exotic physics such as neutrino decay, Lorentz symmetry violation, pseudo-Dirac effects, CP and CPT violation and quantum decoherence. This allows us to probe hitherto unexplored ranges of parameters for the above cases, for example lifetimes in the range $ 10^{-3}-10^{4} $ s/eV for the case of neutrino decay. We show that standard neutrino oscillations ensure that the different flavours arrive at the earth with similar shapes even if their flavour spectra at source may differ strongly in both shape and magnitude. As a result, observed differences between the spectra of various flavours at the detector would be signatures of non-standard physics altering neutrino fluxes during propagation rather than those arising during their production at source. Since detection of ultra-high energy (UHE) neutrinos is perhaps imminent, it is possible that such differences in spectral shapes will be tested in neutrino detectors in the near future. To that end, using the IceCube detector as an example, we show how our results translate to observable shower and muon-track event rates.
description: 16 pages, 10 figures
Winter behaviour and population structure of fin whales (Balaenoptera physalus) in British Columbia inferred from passive acoustic data
Creators: name: Koot, Barbara
Publisher: name: University of British Columbia
Year: 2015

description: Fin whales are acoustically active year-round, particularly during the winter breeding season when males produce song as a reproductive display. Little is known about movement patterns and population structure of the fin whale (Balaenoptera physalus) in the North Pacific. I used passive acoustic data recorded using bottom-mounted autonomous recording instruments to answer questions about the winter distribution, behaviour and population structure of fin whales in a high-latitude area of the eastern North Pacific Ocean. I found that fin whales are present in British Columbia (BC) waters throughout the winter, and their acoustic behaviour suggests that they are engaging in reproductive and possibly feeding behaviour. The presence of these individuals indicates that not all fin whales migrate south in the winter to low-latitude breeding grounds. I found that the majority of fin whales recorded in BC sang a doublet song with alternating ~13 s and ~17 s intervals between alternating classic and backbeat notes (song Type 2). At the most northerly recording site, and the two offshore sites, I found a few instances of a previously described doublet song type that has longer internote intervals (song Type 1). This suggests that two spatially segregated populations of fin whales are using BC waters, with the population producing song Type 2 being more coastal. Through a literature search, I found evidence of song Type 2 occurring from northern BC to Oregon. Song Type 1 has been documented off Southern California, the Bering Sea and the central North Pacific. My results are consistent with evidence showing that two genetically distinct fin whale populations occur in the eastern North Pacific, and that the population that produces song Type 2 is more closely related to the Southern Hemisphere subspecies of fin whale, than to the other population of fin whales in the North Pacific. My results show that BC waters are important for fin whales year-round, rather than just during the summer feeding season―and that the fin whales in BC likely belong to two distinct populations (one of which may belong to the Southern Hemisphere subspecies) and may require separate plans for their conservation and management.
Additional file 1 of Efficacy of intrauterine insemination in women with endometrioma-associated subfertility: analysis using propensity score matching
Creators: name: Cai, He
name: Xie, Jinlin
name: Shi, Juanzi
name: Wang, Hui
Publisher: name: figshare
Year: 2022
Subjects: Medicine
Cell Biology
Biotechnology
Chemical Sciences not elsewhere classified
Mathematical Sciences not elsewhere classified
Cancer
Science Policy

description: Additional file 1. Clinical parameters in women with endometrioma-associated subfertility.
New aspects of the Z$_{\textrm 2}$ $\times$ Z$_{\textrm 2}$-graded 1D superspace: induced strings and 2D relativistic models
Creators: name: Aizawa, N.
name: Ito, R.
name: Kuznetsova, Z.
name: Toppan, F.
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: A novel feature of the ${\mathbb Z}_2\times {\mathbb Z}_2$-graded supersymmetry which finds no counterpart in ordinary supersymmetry is the presence of $11$-graded exotic bosons (implied by the existence of two classes of parafermions). Their interpretation, both physical and mathematical, presents a challenge. The role of the "exotic bosonic coordinate" was not considered by previous works on the one-dimensional ${\mathbb Z}_2\times {\mathbb Z}_2$-graded superspace (which was restricted to produce point-particle models). By treating this coordinate at par with the other graded superspace coordinates new consequences are obtained. The graded superspace calculus of the ${\mathbb Z}_2\times {\mathbb Z}_2$-graded worldline super-Poincaré algebra induces two-dimensional ${\mathbb Z}_2\times {\mathbb Z}_2$-graded relativistic models; they are invariant under a new ${\mathbb Z}_2\times {\mathbb Z}_2$-graded $2D$ super-Poincaré algebra which differs from the previous two ${\mathbb Z}_2\times {\mathbb Z}_2$-graded $2D$ versions of super-Poincaré introduced in the literature. In this new superalgebra the second translation generator and the Lorentz boost are $11$-graded. Furthermore, if the exotic coordinate is compactified on a circle ${\bf S}^1$, a ${\mathbb Z}_2\times {\mathbb Z}_2$-graded closed string with periodic boundary conditions is derived. The analysis of the irreducibility conditions of the $2D$ supermultiplet implies that a larger $(β$-deformed, where $β\geq 0$ is a real parameter) class of point-particle models than the ones discussed so far in the literature (recovered at $β=0$) is obtained. While the spectrum of the $β=0$ point-particle models is degenerate (due to its relation with an ${\cal N}=2$ supersymmetry), this is no longer the case for the $β> 0$ models.
description: 28 pages
Plasma heating in the very early and decay phases of solar flares
Creators: name: Falewicz, R.
name: Siarkowski, M.
name: Rudawy, P.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: In this paper we analyze the energy budgets of two single-loop solar flares under the assumption that non-thermal electrons are the only source of plasma heating during all phases of both events. The flares were observed by the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and Geostationary Operational Environmental Satellite (GOES) on September 20, 2002 and March 17, 2002, respectively. For both investigated flares we derived the energy fluxes contained in non-thermal electron beams from the RHESSI observational data constrained by observed GOES light-curves. We showed that energy delivered by non-thermal electrons was fully sufficient to fulfil the energy budgets of the plasma during the pre-heating and impulsive phases of both flares as well as during the decay phase of one of them. We concluded that in the case of the investigated flares there was no need to use any additional ad-hoc heating mechanisms other than heating by non-thermal electrons.
description: 22 pages, 10 figures, The Astrophysical Journal (accepted, March 2011)
New Decisions Farmers Must Make in Contract Farming
Creators: name: Upchurch, M. L.
Publisher: name: Unknown
Year: 1958
Subjects: Farm Management
Risk and Uncertainty

description: Excerpts: Contract farming is not a new way of doing business. Rather it is an adaptation to agriculture of methods and techniques commonly used in other sectors of our economy. Properly prepared production contracts help farmers "nail down" the future. With a good production contract, a farmer may more confidently obligate himself for labor, credit, or other items needed to produce the kind and quantity of goods specified in the agreement. Use of the contract as a business tool is as much of an innovation in farming as adoption of a new machine or a new insecticide. The technological revolution in agriculture is working a relative hardship on farmers who have not been able to participate in the technological changes. The competitive position between farmers who can innovate and farmers who cannot innovate is widening. I submit that this is also true with respect to our economic revolution. Farmers who cannot innovate in their ways of doing business will become less and less able to compete with farmers who do innovate. Contract farming is one form of innovation that will increase in importance.
description: Talk prepared for delivery before a joint seminar of staff members of the Federal Extension Service and the Farmer Cooperative Service, Washington, D.C., Oct. 23, 1958.
Synthetic spin-orbit coupling for the multispin models in optical lattices
Creators: name: Zheng, Zhen
name: Zhu, Yan-Qing
name: Zhang, Shanchao
name: Zhu, Shi-Liang
name: Wang, Z. D.
Publisher: name: arXiv
Year: 2024
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: The essential role of synthetic spin-orbit coupling in discovering new topological matter phases with cold atoms is widely acknowledged. However, the engineering of spin-orbit coupling remains unclear for arbitrary-spin models due to the complexity of spin matrices. In this paper, we develop a more general but relatively straightforward method to achieve spin-orbit coupling for multispin models. Our approach hinges on controlling the coupling between distinct pseudo-spins through two intermediary states, resulting in tunneling with spin flips that have direction-dependent strength. The engineered spin-orbit coupling can facilitate topological phase transitions with Chern numbers over 1, a unique characteristic of multispin models compared to spin-1/2 models. By utilizing existing cold atom techniques, our proposed method provides an ideal platform for investigating topological properties related to large Chern numbers.
description: 10 pages, 6 figures
Current applications of the sonogashira reaction in the synthesis of heterocyclic compounds: An update
Creators: name: Mommahed Heravi, Majid
name: Ghanbarian, Manizheh
name: Ghalavand, Nastaran
name: Nazari, Niousha
Publisher: name: figshare
Year: 2022
Subjects: subject: 30302 Nanochemistry and Supramolecular Chemistry
subject: FOS: Chemical sciences
subject: 30502 Natural Products Chemistry
subject: 30205 Non-metal Chemistry
subject: Nuclear Chemistry
subject: 30503 Organic Chemical Synthesis
subject: 30303 Optical Properties of Materials
subject: 30599 Organic Chemistry not elsewhere classified
subject: 30504 Organic Green Chemistry
subject: Organic Chemistry

description: The Sonogashira cross-coupling reaction involves the coupling of terminal alkynes with aryl or vinyl halides in the presence of a Pd and a Cu(I) co-catalyst. We tried to reveal the importance of the applications of the Sonogashira reaction in the synthesis of heterocyclic compounds.The reactions occur under relatively mild conditions and tolerate a wide variety of functional groups.
Do We Have Any Viable Solution to the Measurement Problem?
Creators: name: Adlam, Emily
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: History and Philosophy of Physics (physics.hist-ph)
subject: FOS: Physical sciences

description: Wallace (2022) has recently argued that a number of popular approaches to the measurement problem can't be fully extended to relativistic quantum mechanics and quantum field theory; Wallace thus contends that as things currently stand, only the unitary-only approaches to the measurement problem are viable. However, the unitary-only approaches face serious epistemic problems which may threaten their viability as solutions, and thus we consider that it remains an urgent outstanding problem to find a viable solution to the measurement problem which can be extended to relativistic quantum mechanics. In this article we seek to understand in general terms what such a thing might look like. We argue that in order to avoid serious epistemic problems, the solution must be a single-world realist approach, and we further argue that any single-world realist approach which is able to reproduce the predictions of relativistic quantum mechanics will most likely have the property that our observable reality does not supervene on dynamical, precisely-defined microscopic beables. Thus we suggest three possible routes for further exploration: observable reality could be approximate and emergent, as in relational quantum mechanics with the addition of cross-perspective links, or observable reality could supervene on beables which are not microscopically defined, as in the consistent histories approach, or observable reality could supervene on beables which are not dynamical, as in Kent's solution to the Lorentzian classical reality problem. We conclude that once all of these issues are taken into account, the options for a viable solution to the measurement problem are significantly narrowed down.
Modular development of deep potential for complex solid solutions
Creators: name: Wu, Jing
name: Yang, Jiyuan
name: Ma, Liyang
name: Zhang, Linfeng
name: Liu, Shi
Publisher: name: arXiv
Year: 2023
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The multicomponent oxide solid solution is a versatile platform to tune the delicate balance between competing spin, charge, orbital, and lattice degrees of freedom for materials design and discovery. The development of compositionally complex oxides with superior functional properties has been largely empirical and serendipitous, in part due to the exceedingly complex chemistry and structure of solid solutions that span a range of length scales. The classical molecular dynamics (MD), as a powerful statistical method to investigate materials properties over large spatial and temporal scales, often plays a secondary role in computer-aided materials discovery because of the limited availability and accuracy of classical force fields. Here, we introduce the strategy of ``modular developing deep potential" (ModDP) that enables a systematic development and improvement of deep neural network-based model potential, termed as deep potential, for complex solid solutions with minimum human intervention. The converged training database associated with an end-member material is treated as an independent module and is reused to train the deep potential of solid solutions via a concurrent learning procedure. We apply ModDP to obtain classical force fields of two technologically important solid solutions, Pb$_x$Sr$_{1-x}$TiO$_3$ and Hf$_x$Zr$_{1-x}$O$_2$. For both materials systems, a single model potential is capable of predicting various properties of solid solutions including temperature-driven and composition-driven phase transitions over a wide range of compositions. In particular, the deep potential of Pb$_x$Sr$_{1-x}$TiO$_3$ reproduces a few known topological textures such as polar vortex lattice and electric dipole waves in PbTiO$_3$/SrTiO$_3$ superlattices, paving the way for MD investigations on the dynamics of topological structures in response to external stimuli.
description: 32 pages, 9 figures
Mathematical and numerical analysis of a model for anti-angiogenic therapy in metastatic cancers
Creators: name: Benzekry, Sebastien
Publisher: name: arXiv
Year: 2010
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: We introduce and analyze a phenomenological model for anti-angiogenic therapy in the treatment of metastatic cancers. It is a structured transport equation with a nonlocal boundary condition describing the evolution of the density of metastasis that we analyze first at the continuous level. We present the numerical analysis of a lagrangian scheme based on the characteristics whose convergence establishes existence of solutions. Then we prove an error estimate and use the model to perform interesting simulations in view of clinical applications.
description: Nombre de pages : 29
Attentional requirements of postural control in people with spinal cord injury : the effect of dual task
Creators: name: Tse, Cynthia Munting
Publisher: name: University of British Columbia
Year: 2015

description: Background: The simultaneous performance of a postural and suprapostural task has been shown to result in the deterioration of the performance of one or both tasks. For people with spinal cord injury (SCI), whose standing balance is challenged, it is unknown the extent to which they rely on attentional resources to maintain quiet stance. The overall aim of this study was to use a dual task paradigm to investigate the attentional requirements for maintaining standing balance in people with SCI. Methods: We recruited 9 adults with incomplete SCI and 8 matched able-bodied controls. Subjects were asked to perform two suprapostural tasks: a mathematical task (counting backwards by 3s) and an auditory reaction time (RT) task with eyes open/closed. Three single task (ST) trials were recorded: i) standing on force plates; ii) math task while seated; iii) RT task while seated. Two dual-task (DT) trials were recorded: i) standing + math task; ii) standing + RT task. The primary outcome measures were the change in performance between ST and DT between SCI and controls for: i) RT, ii) maximum standing time, iii) error ratio and total number of words uttered, and iv) movement reinvestment. Secondary outcomes such as center of pressure (CoP) measures from force plates as well as perceptual measures such as fear, confidence and perceived mental workload were also recorded. Results: SCI subjects stood for shorter duration during DT (stand and count) than ST (stand) compared to controls during eyes closed. Main effects between groups were observed for movement reinvestment, CoP performance, perceived mental effort, fear and confidence. No significant effects were observed for RT task or math task performance. Conclusion: Total standing time during eyes closed is adversely affected with the addition of a math task for SCI subjects. Perceptual measures such as increased fear and perceived mental workload and decreased confidence correspond to increases in postural sway and conscious control of standing in subjects with SCI. Individuals who can stand for >60 seconds eyes closed do not appear to be significantly affected by the addition of a concurrent secondary task of minimal mental workload.
Geneverse: A collection of Open-source Multimodal Large Language Models for Genomic and Proteomic Research
Creators: name: Liu, Tianyu
name: Xiao, Yijia
name: Luo, Xiao
name: Xu, Hua
name: Zheng, W. Jim
name: Zhao, Hongyu
Publisher: name: arXiv
Year: 2024
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: Computation and Language (cs.CL)
subject: Quantitative Methods (q-bio.QM)
subject: FOS: Computer and information sciences
subject: FOS: Biological sciences

description: The applications of large language models (LLMs) are promising for biomedical and healthcare research. Despite the availability of open-source LLMs trained using a wide range of biomedical data, current research on the applications of LLMs to genomics and proteomics is still limited. To fill this gap, we propose a collection of finetuned LLMs and multimodal LLMs (MLLMs), known as Geneverse, for three novel tasks in genomic and proteomic research. The models in Geneverse are trained and evaluated based on domain-specific datasets, and we use advanced parameter-efficient finetuning techniques to achieve the model adaptation for tasks including the generation of descriptions for gene functions, protein function inference from its structure, and marker gene selection from spatial transcriptomic data. We demonstrate that adapted LLMs and MLLMs perform well for these tasks and may outperform closed-source large-scale models based on our evaluations focusing on both truthfulness and structural correctness. All of the training strategies and base models we used are freely accessible.
description: 8 pages
Functional integral representations for quantum many-particle systems
Creators: name: Blois, Cindy Marie
Publisher: name: University of British Columbia
Year: 2015

description: Formal functional integrals are commonly used as theoretical tools and as sources of intuition for predicting phase transitions of many-body systems in Condensed Matter Physics. In this thesis, we derive rigorous versions of these functional integrals for two types of quantum many-particle systems. We begin with a brief review of quantum statistical mechanics in Chapter 2 and the formalism of coherent states in Chapter 3, which form the basis for our analysis in Chapters 4 and 5. In Chapter 4, we study a mixed gas of bosons and/or fermions interacting on a finite lattice, with a general Hamiltonian that preserves the total number of particles in each species. We rigorously derive a functional integral representation for the partition function, which employs a large-field cutoff for the boson fields. We then expand the resulting “action” in powers of the fields and find a recursion relation for the coefficients. In the case of a two-body interaction (such as the Coulomb interaction), we also find bounds on the coefficients, which give a domain of analyticity for the action. This domain is large enough for use of the action in the functional integral, provided that the large-field cutoffs are taken to grow not too quickly. In Chapter 5, we study a system of electrons and phonons interacting in a finite lattice, using the Holstein Hamiltonian. Again, we rigorously derive a coherent-state functional integral representation for the partition function of this system and then prove that the “action” in the functional integral is an entire-analytic function of the fields. However, since the Holstein Hamiltonian does not preserve the total number of bosons, the approach from Chapter 4 requires some modification. In particular, we repeatedly use Duhamel expansions in powers of the interaction, rather than sums over particle numbers.
Terahertz spin ratchet effect in magnetic metamaterials
Creators: name: Hild, M.
name: Golub, L. E.
name: Fuhrmann, A.
name: Otteneder, M.
name: Kronseder, M.
name: Matsubara, M.
name: Kobayashi, T.
name: Oshima, D.
name: Honda, A.
name: Kato, T.
name: Wunderlich, J.
name: Back, C.
name: Ganichev, S. D.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We report on spin ratchet currents driven by terahertz radiation electric fields in a Co/Pt magnetic metamaterial formed by triangle-shaped holes forming an antidots lattice and subjected to an external magnetic field applied perpendicularly to the metal film plane. We show that for a radiation wavelength substantially larger than the period of the antidots array the radiation causes a polarization-independent spin-polarized ratchet current. The current is generated by the periodic asymmetric radiation intensity distribution caused by the near-field diffraction at the edges of the antidots, which induces spatially inhomogeneous periodic electron gas heating, and a phase-shifted periodic asymmetric electrostatic force. The developed microscopic theory shows that the magnetization of the Co/Pt film results in a spin ratchet current caused by both the anomalous Hall and the anomalous Nernst effects. Additionally, we observed a polarization-dependent trigonal spin photocurrent, which is caused by the scattering of electrons at the antidot boundaries resulting in a spin-polarized current due to the magnetization. Microscopic theory of these effects reveals that the trigonal photocurrent is generated at the boundaries of the triangle antidots, whereas the spin ratchet is generated due to the spatially periodic temperature gradient over the whole film. This difference causes substantially different hysteresis widths of these two currents.
description: 16 pages, 13 figures
Three essays in the economics of education : evidence from Canadian policies
Creators: name: Duhaime-Ross, Alix
Publisher: name: University of British Columbia
Year: 2015

description: This dissertation evaluates the effects of various public policies related to education in Canada. Chapter 2 analyses the long-term effects of mandating immigrant children to attend school in the language of the majority. Using the 1977 introduction of Bill 101 in Quebec, a law that compelled children, with some exceptions, to attend school in French, I identify the impacts of studying in French on first- and second-generation immigrant children in Quebec. I find strong evidence that the law led to a significant increase in immigrants’ propensity to use French at home and at work, in their probability of being employed or in school, being part of the labour force, and choosing to live outside of the Montreal metropolitan area. Chapter 3 tests the empirical predictions of three theoretical saving frameworks in the context of saving for a child’s post-secondary education: the life-cycle saving model, the fixed-goal saving model, and the procrastination saving model. Using regression discontinuity and panel data regression techniques, I evaluate the effects of three Canadian education saving incentive programs on parents’ saving behaviour in Registered Education Savings Plans (RESPs). The results indicate that the actions of parents are generally consistent with the procrastination saving model. I estimate that higher matching rates on contributions and lump-sum subsidies increased RESP contributions and savings among lower-income families who applied for the programs. Furthermore, grants conditional on opening an account generally caused all parents to start saving earlier for their child. Chapter 4 evaluates the impacts of education savings in incentivised education savings accounts on children’s overall education savings and their academic performance. To identify these effects, I employ an instrumental variable approach that relies on the structure of Canadian saving incentives offered to parents for contributions to RESPs. I find no effect of the saving incentives on parents’ overall decision to save for their child’s post-secondary education. Among parents who do save, I estimate a small but significant crowding-out effect of RESP savings on education savings in other types of saving vehicles. Finally, I find no evidence of a causal impact of savings in RESPs on children’s performance in school.
title: Basin Inventory Adavale Basin
Creators: name: T., Palu
name: R., Korsch
Publisher: name: Commonwealth of Australia (Geoscience Australia)
Year: 2023
Subjects: subject: Basin Analysis
subject: GEOLOGY
subject: Petroleum and Reservoir Engineering
subject: EARTH SCIENCES
subject: Adavale Basin
subject: EFTF - Exploring for the Future
subject: Published_External

description: A large proportion of Australia’s onshore sedimentary basins remain exploration frontiers. Industry interest in these basins has recently increased due to the global and domestic energy demand, and the growth in unconventional hydrocarbon exploration. In 2016 and 2018, Geoscience Australia released an assessment of several central Australian basins that summarised the current status of geoscientific knowledge and petroleum exploration, and the key questions, for each basin. This publication provides a comprehensive assessment of the geology, petroleum systems, exploration status and data coverage for the Adavale Basin.
A new z=0 metagalactic UV background limit
Creators: name: Adams, Joshua J.
name: Uson, Juan M.
name: Hill, Gary J.
name: MacQueen, Phillip J.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We present new integral-field spectroscopy in the outskirts of two nearby, edge-on, late-type galaxies to search for the H-alpha emission that is expected from the exposure of their hydrogen gas to the metagalactic ultraviolet background (UVB). Despite the sensitivity of the VIRUS-P spectrograph on the McDonald 2.7m telescope to low surface brightness emission and the large field-of-view, we do not detect H-alpha to 5 sigma upper limits of 6.4 x 10^(-19) erg/s/cm^2/arcsec^2 in UGC 7321 and of 25 x 10^(-19) erg/s/cm^2/arcsec^2 in UGC 1281 in each of the hundreds of independent spatial elements (fibers). We fit gas distribution models from overlapping 21 cm data of HI, extrapolate one scale length beyond the HI data, and estimate predicted H-alpha surface brightness maps. We analyze three types of limits from the data with stacks formed from increasingly large spatial regions and compare to the model predictions: 1) single fibers, 2) convolution of the fiber grid with a Gaussian, circular kernel (10\arcsec\ full width half maximum), and 3) the coadded spectra from a few hundred fibers over the brightest model regions. None of these methods produce a significant detection (>5 sigma) with the most stringent constraints on the HI photoionization rate of Gamma(z=0)<1.7 x 10^(-14) s^(-1) in UGC 7321 and Gamma(z=0)<14 x 10^(-14) s^(-1) in UGC 1281. The UGC 7321 limit is below previous measurement limits and also below current theoretical models. Restricting the analysis to the fibers bound by the HI data leads to a comparable limit; the limit is Gamma(z=0)<2.3 x 10^(-14) s^(-1) in UGC 7321. We discuss how a low Lyman limit escape fraction in z~0 redshift star forming galaxies might explain this lower than predicted UVB strength and the prospects of deeper data to make a direct detection.
description: accepted to ApJ; 16 pages, 6 figures, 2 tables
The transition of British Columbia’s tertiary psychiatric services from hospital to community : consideration of clinical, psychosocial, and transinstitutionalization outcomes
Creators: name: Petersen, Karen Leanne
Publisher: name: University of British Columbia
Year: 2015

description: Deinstitutionalization of severely and persistently mentally ill individuals has been one of the most significant developments in mental health policy and practice in the last 70 years. This dissertation is comprised of four interconnected papers which together examine the redevelopment of tertiary psychiatric services in British Columbia (BC). The first paper reports on a cohort of patients who moved from Riverview Hospital (RVH), BC’s only large-scale tertiary psychiatric hospital, to community-based facilities in the Vancouver Island, Interior, Northern, and Fraser Health Authorities between 2001 and 2004. The variety and characteristics of the facilities participants moved to over the course of the RVH closure and changes in clinical and psychosocial characteristics of participants over a 5-year period are described. The next paper considers the psychosocial, clinical, and risk profile of the final cohort of RVH patients and compares and contrasts those characteristics with a forensic sample. In addition, the prevalence of a variety of negative outcomes (i.e., aggression, inappropriate sexual behaviour, self-harm, suicide, self-neglect, unauthorized leave, substance abuse, victimization, and stalking) in a six month time frame are compared. The third paper is a validation of the Short-Term Assessment of Risk and Treatability (START) in forensic mental health practice. It addresses three specific research questions: (1) What is the clinical and risk profile of a large Canadian forensic psychiatric cohort? (2) What are the psychometric properties of the START in a forensic service when the evaluations are completed by clinical teams? (3) How are these profiles and START outcomes similar or different among male and female patients and across various settings (i.e., hospital versus clinic) or security levels (i.e., maximum, medium, minimum)? The fourth paper compares the psychometric properties of START in a forensic and civil psychiatric sample. The results from this dissertation provide evidence that a well-planned and well-resourced closure of a civil psychiatric hospital do not lead to negative outcomes such as transinstitutionalization and homelessness and suggest that START is a potentially useful tool for psychiatric patients.
Search for a light Higgs boson with the BABAR detector : with proposals to improve drift chamber aging studies and particle identification
Creators: name: So, Rocky Yat Cheung
Publisher: name: University of British Columbia
Year: 2015

description: In the Standard Model of particle physics, the Higgs boson is an elementary particle required to explain the origin of mass. One extension, the next-to-minimal supersymmetric Standard Model, predicts the existence of a GeV/c² scale Higgs boson, denoted A^0. This can be produced at B meson factories such as the BABAR experiment at the Stanford Linear Accelerator Center. We study e⁺e- → Υ(2S)→ π⁺π-Y(1S), Y(1S)→ γA^0, A^0 → gg, ss-bar, cc-bar decays using data collected by the BABAR detector at a centre-of-mass energy of 10.02 GeV/c². The search for A^0 → gg or ss-bar is performed by fully reconstructing the entire decay chain. We search for an excess of events relative to expected backgrounds in the reconstructed A^0 mass spectra. No significant excess is found. We set upper limits on product branching fraction B(Y(1S) → γA^0)xB(A^0 → gg) from 1x10-⁶ to 2x10-² for A^0 masses from 0.50 to 9.00 GeV/c², and B(Y(1S) → γA^0)x B(A^0 → ss-bar) from 5x10-⁶ to 1x10-³ for A^0 masses from 1.50 to 9.00 GeV/c². The search for A^0 → cc-bar is done by reconstructing the dipion transition, the radiative photon, and a D meson as a tag for cc-bar decays. We infer the mass of an A^0 candidate from the recoil of the dipion transition and the radiative photon. No significant signal is seen in the data and we set upper limits on product branching fraction B(Y(1S) → γA^0)xB(A^0 → cc-bar) from 7x10-⁵ to 2x10-³ for A^0 masses from 4.00 to 8.95 GeV/c² and 9.10 to 9.25 GeV/c². These are the first measurements to date and set constraints on the next-to-minimal supersymmetric Standard Model. Proposals to improve drift chamber aging studies and particle identification are included as part of the thesis. We propose to improve aging studies with prototypes that better resemble a full-scale drift chamber. Using TRIUMF beam data, we establish that at a particle identification efficiency of 95%, misidentification rates may be reduced from 2.2% to 1.9% by including likelihood tests and Kolmogorov-Smirnov tests and to 0.5% by including cluster counting.
PtyLab.m/py/jl: a cross-platform, open-source inverse modeling toolbox for conventional and Fourier ptychography
Creators: name: Loetgering, Lars
name: Du, Mengqi
name: Flaes, Dirk Boonzajer
name: Aidukas, Tomas
name: Wechsler, Felix
name: Molina, Daniel S. Penagos
name: Rose, Max
name: Pelekanidis, Antonios
name: Eschen, Wilhelm
name: Hess, Jürgen
name: Wilhein, Thomas
name: Heintzmann, Rainer
name: Rothhardt, Jan
name: Witte, Stefan
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computational Physics (physics.comp-ph)
subject: Image and Video Processing (eess.IV)
subject: Optics (physics.optics)
subject: FOS: Physical sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Conventional (CP) and Fourier (FP) ptychography have emerged as versatile quantitative phase imaging techniques. While the main application cases for each technique are different, namely lens-less short wavelength imaging for CP and lens-based visible light imaging for FP, both methods share a common algorithmic ground. CP and FP have in part independently evolved to include experimentally robust forward models and inversion techniques. This separation has resulted in a plethora of algorithmic extensions, some of which have not crossed the boundary from one modality to the other. Here, we present an open source, cross-platform software, called PtyLab, enabling both CP and FP data analysis in a unified framework. With this framework, we aim to facilitate and accelerate cross-pollination between the two techniques. Moreover, the availability in Matlab, Python, and Julia will set a low barrier to enter each field.
The fate of fertilizer nitrogen in raspberry production as affected by nitrogen inputs and irrigation regime : an experiment in the Fraser Valley, British Columbia
Creators: name: Armstrong, Nathalie Monica
Publisher: name: University of British Columbia
Year: 2015

description: The lower Fraser Valley is an important agricultural region in British Columbia, Canada whose central portion is underlain by the Abbotsford-Sumas Aquifer. The aquifer has been identified as vulnerable and high concentrations of nitrate that have been linked to application of nitrogen (N) fertilizers to crops, particularly red raspberry. The region has the most concentrated raspberry production in Canada and therefore raspberry management has the potential to influence N losses to the aquifer. The goal of this study was to determine how variations in irrigation and N fertilization affect the fate of N from fertilizer (NFF) from one year’s application in order to identify practices that maximize crop acquisition of N and minimize the risks of nitrate leaching. Specific practices that were compared include rate of N inputs (50 vs. 100 kg N ha-¹), mode of N application (fertigation vs. broadcast), and irrigation method (fixed schedule vs. plant need based). To determine the influences of different management practices, the fate of NFF was traced by applying ¹⁵N labeled fertilizer in April and May 2011, as a split application, and then analyzing movement of the ¹⁵N into plant tissues, leachate, and soil at four critical times during the subsequent year. This study found that irrigation regime had a strong influence on N losses by leaching. Reduced water inputs reduced nitrate -N leaching and did not negatively affect productivity. Fertigation, which employed a combination of reduced N and water inputs, improved plant acquisition of NFF, resulting in reduced leaching of nitrate-N. The 50 kg N ha-¹ treatments produced berry yields comparable to the 100 kg N ha-¹ treatments while the higher N inputs resulted in greater NFF being removed from the system by berry harvest and pruning. Peak plant uptake of NFF was found to be in July 2011 with the maximum held in the floricane component. By August, NFF content in both the floricane and primocane components had decreased and the primocane component had relocated NFF from the leaves to the cane. After the drop between July and August, NFF in the system remained relatively stable into the following growing season.
Mach-like emission from nucleon scattering in proton-nucleus reaction
Creators: name: Zhang, G. Q.
name: Ma, Y. G.
name: Cao, X. G.
name: Zhou, C. L
Publisher: name: arXiv
Year: 2011
Subjects: subject: Nuclear Theory (nucl-th)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: The fast-stage nucleon emission of proton-nucleus (pA) reactions from 300A MeV to 1.8A GeV has been investigated using the quantum molecular-dynamics model. It is found that the sideward angular spectrum of nucleon emission presents an interesting Mach-like structure at the early stage of the collision (tens of fm/c). The sideward angular peak value varies from about 45\circ to near 73\circ, depending on the bombarding energy. Nucleons emitted from the vicinity of the sideward peak tend to have a fixed momentum value about 0.5 GeV/c, independent of the bombarding energy as well as the impact parameter. Additionally, the sideward angular peak value is almost independent of the equation of state, indicating that binary collision at the early fast stage in the intermediate energy pA reaction plays an important role in the emergence of Mach-like emission.
description: 4 pages, 6 figures
Joint constraints on cosmological parameters using future multi-band gravitational wave standard siren observations
Creators: name: Jin, Shang-Jie
name: Xing, Shuang-Shuang
name: Shao, Yue
name: Zhang, Jing-Fei
name: Zhang, Xin
Publisher: name: arXiv
Year: 2023
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Gravitational waves (GWs) from the compact binary coalescences can be used as standard sirens to explore the cosmic expansion history. In the next decades, it is anticipated that we could obtain the multi-band GW standard siren data (from nanohertz to a few hundred hertz), which are expected to play an important role in cosmological parameter estimation. In this work, we give for the first time the joint constraints on cosmological parameters using the future multi-band GW standard siren observations. We simulate the multi-band GW standard sirens based on the SKA-era pulsar timing array (PTA), the Taiji observatory, and the Cosmic Explorer (CE) to perform cosmological analysis. In the $Λ$CDM model, we find that the joint PTA+Taiji+CE data could provide a tight constraint on the Hubble constant with a $0.5\%$ precision. Moreover, PTA+Taiji+CE could break the cosmological parameter degeneracies generated by CMB, especially in the dynamical dark energy models. When combining the PTA+Taiji+CE data with the CMB data, the constraint precisions of $Ω_{\rm m}$ and $H_0$ are $1.0\%$ and $0.3\%$, meeting the standard of precision cosmology. The joint CMB+PTA+Taiji+CE data give $σ(w)=0.028$ in the $w$CDM model and $σ(w_0)=0.11$ and $σ(w_a)=0.32$ in the $w_0w_a$CDM model, which are comparable with or close to the latest constraint results by CMB+BAO+SN. In conclusion, it is worth expecting to use the future multi-band GW observations to explore the nature of dark energy and measure the Hubble constant.
description: 12 pages, 6 figures; accepted for publication in Chinese Physics C