cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Regulation of intestinal inflammation by CD45
Creators: name: Samarakoon, Asanga
Publisher: name: University of British Columbia
Year: 2017

description: Factors secreted by intestinal immune cells such as retinoic acid and cytokines are crucial in maintaining homeostasis in the gut. Dysregulation in the secretion of these factors can lead to inflammation and development of colitis. CD45 is a leukocyte specific tyrosine phosphatase important for T cell development and antigen receptor signaling. Here, I show that upon DSS-induced colitis, CD45-/- mice unexpectedly have significant numbers of T cells in their colon and exhibit more severe colitis. This was attributed to increased expression of the gut homing molecule, α4β7 and increased production of IFNγ and IL17A by the CD45-/- T cells. However, in the absence of adaptive immunity, CD45 is required for optimal intestinal innate immune responses. CD45-/- innate lymphoid cells had decreased IL-22 and GM-CSF production and CD45-/- myeloid cells have lower retinoic acid production. This led to less severe colitis when CD45 ⁺/⁺ T cells were transferred into CD45RAG-/- mice as it led to reduced expression of gut homing molecules and reduced homing of T cells to the colon. This defect was corrected by the addition of GM-CSF, which restored retinoic acid production. Induction of colitis by the transfer of naïve T cells into RAG-/- and CD45RAG-/- mice delayed the development of systemic disease in CD45RAG-/- mice, but led to comparable intestinal inflammation at the RAG-/- weight loss endpoint and significantly greater inflammation at the CD45RAG-/- endpoint, corresponding with increased CD45-/- myeloid cells in the colon. Since there was no difference in Foxp3+ regulatory T cells systemically, other options of inhibition of systemic inflammation in CD45RAG-/- mice were explored. CD45RAG-/- mice had increased CD71+TER119+ erythroid cells in the spleen prior to and post colitis induction and failed to downregulate erythroid progenitors upon T cell induced colitis. These suppressive erythroid cells may contribute to the delayed systemic inflammation in these mice. Overall, these results show novel roles for CD45 in the regulation of innate and adaptive immune cell cytokine production, as well as in erythrocyte maturation.
Sequential Editing for Lifelong Training of Speech Recognition Models
Creators: name: Kulshreshtha, Devang
name: Dingliwal, Saket
name: Houston, Brady
name: Pappas, Nikolaos
name: Ronanki, Srikanth
Publisher: name: arXiv
Year: 2024
Subjects: subject: Computation and Language (cs.CL)
subject: Sound (cs.SD)
subject: Audio and Speech Processing (eess.AS)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Automatic Speech Recognition (ASR) traditionally assumes known domains, but adding data from a new domain raises concerns about computational inefficiencies linked to retraining models on both existing and new domains. Fine-tuning solely on new domain risks Catastrophic Forgetting (CF). To address this, Lifelong Learning (LLL) algorithms have been proposed for ASR. Prior research has explored techniques such as Elastic Weight Consolidation, Knowledge Distillation, and Replay, all of which necessitate either additional parameters or access to prior domain data. We propose Sequential Model Editing as a novel method to continually learn new domains in ASR systems. Different than previous methods, our approach does not necessitate access to prior datasets or the introduction of extra parameters. Our study demonstrates up to 15% Word Error Rate Reduction (WERR) over fine-tuning baseline, and superior efficiency over other LLL techniques on CommonVoice English multi-accent dataset.
description: INTERSPEECH 2024
Role and regulation of Gp78 E3 ubiquitin ligase and its ligand autocrine motility factor in mitochondrial dynamics and mitochondria-endoplasmic reticulum association
Creators: name: Wang, Peter Tien Chun
Publisher: name: University of British Columbia
Year: 2015

description: A ligand-receptor pair, autocrine motility factor (AMF) and Gp78, have been discovered to play multiple roles in mammalian cells. AMF functions as the essential glycolytic enzyme phosphoglucose isomerase in the cytoplasm, but when secreted acts a cytokine that stimulates cell motility, growth and survival. Gp78 serves as the cell surface receptor of AMF, and thus it is also known as AMFR. However, Gp78 can localize to the ER membrane and functions as an E3 ubiquitin ligase in the endoplasmic reticulum associated degradation (ERAD) pathway where it targets a wide variety of proteins for degradation. The concerted actions of AMF and Gp78 contribute to multiple aspects of cancer progression, and thus elevated levels of both proteins have been found in many types of cancers. Recently, it was discovered that AMF and Gp78 alter mitochondrial morphology and ER-mitochondria calcium coupling, processes that are essential in regulating mitochondrial metabolism and apoptosis. Furthermore, Gp78 has also been localized to ER-mitochondria contact sites where it targets the mitochondrial fusion proteins, mitofusin 1 and 2 (Mfn1/2), for degradation. In this dissertation, I show that during Gp78 induced mitophagy, autophagosome marker LC3 is recruited to mitochondria associated ER membrane. Moreover, I show that Gp78-dependent degradation of the mitofusins leads to diminished mitochondrial fusion and a perturbation of mitochondrial dynamics. I also report the ability of AMF to inhibit Gp78-induced mitochondrial fission. In my study of ER-mitochondrial association, I observed two types of ER-mitochondria contacts in HT-1080 fibrosarcoma cells: the rough and the smooth. Gp78 ubiquitin ligase activity selectively promotes rough ER-mitochondria association through the degradation of Mfn2. AMF treatment inhibits Gp78-dependent Mfn2 degradation and decreases rough ER-mitochondria contact sites. By dissecting the functions of AMF and Gp78 at the ER mitochondria contact sites, my thesis not only expands our understanding of the relationship between AMF and Gp78, it also provides novel insights into the intimate connection between the ER and mitochondria.
Performance of timber connections with single and multiple glued-in threaded steel rods
Creators: name: González Barillas, Enrique
Publisher: name: University of British Columbia
Year: 2015

description: The experimental research conducted within this thesis project focused on joints composed of softwood glulam members and mild steel glued-in threaded rods. In a first phase, the influence of the embedment length and the rod diameter using three different adhesives was studied to establish performance benchmarks. In the second phase, the investigation focused on the influence of manufacturing defects on the capacity of timber joints with glued-in steel rods. For this purpose, timber joints were manufactured with two different types of defects likely to be encountered during their manufacturing on-site: i) rods placed at an angle to the drill hole instead of being in the joint axis, and ii) rod placed at the edge of the drill hole instead of fully centred. Finally, in the third phase, joints with multiple rods (two, three and four rods) were manufactured and tested. The adhesive type and rod diameter were kept constant and the embedment length and the spacing between rods were varied during this phase. In all phases of this experimental campaign, specimens were tested under uniaxial quasi-static tension loading. The results showed that, for single glued-in rod joints using mild steel threaded rods, a ductile-type of failure can be consistently attained if the embedment length of the rod is long enough (>10d). Furthermore, the results for specimens with bonding defects considered in this study had no significant negative impact on the capacity of the joints if compared to the results obtained in the first experimental phase. Finally, a spacing between rods greater than four times the rod diameter demonstrated to be sufficient to facilitate a ductile steel yielding failure as long as the joints were manufactured with sufficient embedment length (>10d). The results from this study can contribute towards better understanding of the influence that the parameters under investigation have on the performance on timber joints with glued-in rods, as well as to translate this information to promote the development of more studies on further applications such as moment resisting connections.
Enhancement of superconducting fluctuation under the coexistence of a competing pseudogap state in Bi2Sr2-xRxCuOy
Creators: name: Okada, Y.
name: Kuzuya, Y.
name: Kawaguchi, T.
name: Ikuta, H.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: The onset temperature of superconducting fluctuation Tonset of Bi2Sr2-xRxCuOy (R=La and Eu) was studied by measuring the Nernst effect. We found that Tonset has a x and R dependence that is quite different from both the pseudogap temperature T* and the critical temperature Tc. Our results support the picture that the incoherent superconductivity, which has been observed below Tonset, is qualitatively different from the pseudogap phenomenon that is characterized by T*. The experimentally obtained phase diagram indicates that the pseudogap state suppresses Tc and enhances superconducting fluctuation while having only small influence on Tonset.
Transient jet impaction on a high speed moving surface
Creators: name: Sarraf Shirazi, Alireza
Publisher: name: University of British Columbia
Year: 2015

description: In the railroad industry liquid friction modifiers are applied on the rail track in the form of a liquid jet in order to reduce the friction and fuel consumption. In this application, the transfer efficiency of the liquid on the rail track is very important. To maximize the transfer efficiency, Newtonian and non-Newtonian transient liquid jet impingement on a dry moving surface was studied. Five different water glycerin solutions with widely varying shear viscosities were used as Newtonian test liquids to isolate the effect of shear viscosity from other fluid properties. Furthermore, the effect of surface roughness on the impaction was investigated using four different roughness heights. The effects of jet velocity and surface speed were also studied. High speed imaging was performed to visualize the interaction between the jet and the moving surface. For surface roughness heights between 0.02 μm and 0.64 μm, it was found that as the roughness increases, the jet becomes more prone to splash. It was also shown that increased jet and surface speeds trigger the splash. The transient jet characteristics were also investigated for Newtonian liquids at different nozzle back pressures. It was found that at higher Reynolds and Weber numbers the transient jet breaks up downstream of the nozzle; However, it was shown that the Weber number has the dominant role in jet break-up compared to the Reynolds number. A numerical study was also undertaken to determine the drag force exerted on the plunger of the solenoid valve in the nozzle. The simulation results were in reasonable (16% on average) agreement with experiment.
LLM-Driven Multimodal Opinion Expression Identification
Creators: name: Jia, Bonian
name: Chen, Huiyao
name: Sun, Yueheng
name: Zhang, Meishan
name: Zhang, Min
Publisher: name: arXiv
Year: 2024
Subjects: subject: Computation and Language (cs.CL)
subject: Artificial Intelligence (cs.AI)
subject: Sound (cs.SD)
subject: Audio and Speech Processing (eess.AS)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Opinion Expression Identification (OEI) is essential in NLP for applications ranging from voice assistants to depression diagnosis. This study extends OEI to encompass multimodal inputs, underlining the significance of auditory cues in delivering emotional subtleties beyond the capabilities of text. We introduce a novel multimodal OEI (MOEI) task, integrating text and speech to mirror real-world scenarios. Utilizing CMU MOSEI and IEMOCAP datasets, we construct the CI-MOEI dataset. Additionally, Text-to-Speech (TTS) technology is applied to the MPQA dataset to obtain the CIM-OEI dataset. We design a template for the OEI task to take full advantage of the generative power of large language models (LLMs). Advancing further, we propose an LLM-driven method STOEI, which combines speech and text modal to identify opinion expressions. Our experiments demonstrate that MOEI significantly improves the performance while our method outperforms existing methods by 9.20\% and obtains SOTA results.
description: 5 pages, 3 Figures, Accept by Interspeech 2024
A theory of chemical Reactions in biomolecules in solution: generalized Langevin mode analysis (GLMA)
Creators: name: Hirata, Fumio
Publisher: name: arXiv
Year: 2023
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: The generalized Langevin mode analysis (GLMA) is applied to chemical reactions in biomolecules in solution. The theory sees a chemical reaction in solution as a barrier crossing process, similar to the Marcus theory. The barrier is defined as the crossing point of two free-energy surfaces which are attributed to the reactant and product of the reaction. It is assumed that the both free-energy surfaces are quadratic or harmonic. The assumption is based on the Kim-Hirata theory of structural fluctuation of protein, which proves that the fluctuation around an equilibrium structure is quadratic with respect to the structure or atomic coordinates. The quadratic surface is a composite of many harmonic functions with different modes or frequencies. The height of the activation barrier will be dependent on the mode or frequency, less the frequency, lower the barrier. So, it is essential to decouple the fluctuational mode into a hierarchical order. GLMA is impeccable for this purpose. It is essential for a theoretical study of chemical reactions to chose a reaction coordinate along which the reaction proceeds. We suppose that the mode whose center of coordinate and/or the frequency changes most before and after the reaction is the one relevant to the chemical reaction, and choose the coordinate as the reaction coordinate. The rate of reaction along the reaction coordinate is , which is similar to the Marcus expression for the electron transfer reaction. In the equation, is the activation barrier defined by , where and denote the free energies at equilibrium , and the crossing point , respectively, both on the free energy surface of the reactant.
description: 21 pages, 4 figures, 50 references
Four-nucleon scattering with a correlated Gaussian basis method
Creators: name: Aoyama, S.
name: Arai, K.
name: Suzuki, Y.
name: Descouvemont, P.
name: Baye, D.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: Elastic-scattering phase shifts for four-nucleon systems are studied in an $ab$-$initio$ type cluster model in order to clarify the role of the tensor force and to investigate cluster distortions in low energy $d+d$ and $t+p$ scattering. In the present method, the description of the cluster wave function is extended from a simple (0$s$) harmonic-oscillator shell model to a few-body model with a realistic interaction, in which the wave function of the subsystems are determined with the Stochastic Variational Method. In order to calculate the matrix elements of the four-body system, we have developed a Triple Global Vector Representation method for the correlated Gaussian basis functions. To compare effects of the cluster distortion with realistic and effective interactions, we employ the AV8$^{\prime}$ potential as a realistic interaction and the Minnesota potential as an effective interaction. Especially for $^1S_0$, the calculated phase shifts show that the $t+p$ and $h+n$ channels are strongly coupled to the $d+d$ channel for the case of the realistic interaction. On the contrary, the coupling of these channels plays a relatively minor role for the case of the effective interaction. This difference between both potentials originates from the tensor term in the realistic interaction. Furthermore, the tensor interaction makes the energy splitting of the negative parity states of $^4$He consistent with experiments. No such splitting is however reproduced with the effective interaction.
The origin of the solar magnetic cycle
Creators: name: Choudhuri, Arnab Rai
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: After summarizing the relevant observational data, we discuss how a study of flux tube dynamics in the solar convection zone helps us to understand the formation of sunspots. Then we introduce the flux transport dynamo model and assess its success in modelling both the solar cycle and its departures from strictly periodic behaviour.
description: 18 pages, 14 figures, Proceedings of Chandrasekhar Centenary Conference
The longitudinal energy spread of ion beams extracted from an electron cyclotron resonance ion source
Creators: name: Angot, Julien
name: Tarvainen, Olli
name: Chauveau, Pierre
name: Kosonen, Sami
name: Kalvas, Taneli
name: Thuillier, Thomas
name: Migliore, Myriam
name: Maunoury, Laurent
Publisher: name: arXiv
Year: 2023
Subjects: subject: Accelerator Physics (physics.acc-ph)
subject: FOS: Physical sciences

description: We present a study of factors affecting the energy spread of ion beams extracted from a Charge Breeder Electron Cyclotron Resonance Ion Source (CB-ECRIS). The comprehensive simulations, supported by experiments with a Retarding Field Analyser (RFA), reveal that the longitudinal and transverse energy spread of the extracted beams are strongly affected by the electrostatic focusing effects, namely the extraction geometry and plasma beam boundary, to the extent that the electrostatic effects dominate over the magnetic field induced rotation of the beam or the effect of plasma potential and ion temperature. The dominance of the electrostatic focusing effect over the magnetic field induced rotation complicates parametric studies of the transverse emittance as a function of the magnetic field strength, and comparison of emittance values obtained with different ion sources having different extraction designs. Our results demonstrate that the full ion beam energy spread, relevant for the downstream accelerator, can be measured with the RFA only when all ions are collected. On the contrary, studying the effect of plasma properties (plasma potential and ion temperature) on the longitudinal energy spread requires heavy collimation of the beam accepting only ions near the symmetry axis of the beam for which the electrostatic and magnetic effects are suppressed. As the extraction system of the CB-ECRIS is similar to a conventional ECRIS, the conclusions of the study can be generalised to apply for all high charge state ECR ion sources. Finally, we present the results of systematic plasma potential measurements of the Phoenix-type CB-ECRIS at LPSC, varying the source potential, the microwave power and the axial magnetic field srength. It was observed that the plasma potential increases with the extraction magnetic field and the microwave power.
Caste, religious conflict and economic development : the Indian experience
Creators: name: Roy Chaudhuri, Arka
Publisher: name: University of British Columbia
Year: 2015

description: This thesis aims to understand the economic and political changes in India and how it affects different marginalized groups in India. It looks at the effects of mandated political representation of Scheduled Castes and Scheduled Tribes, the effect of British colonization on Hindu-Muslim conflict in post-Independent India and the evolution of economic conditions of Muslims in India in the past three decades. The first research chapter looks at the effect of political quotas for Scheduled Castes and Scheduled Tribes on households belonging to these groups. Scheduled Castes and Scheduled Tribes form some of the most disadvantaged groups in India. I exploit the policy rule mandating reservations for these groups to identify the effect of political representation of these groups. I find that for Scheduled Caste politicians effectively target narrow based public goods such as participation in workfare program to members of their own ethnic groups but do not do so for broad based public goods such as health, education and access to subsidized food grains. The second research chapter looks at the effect of British colonization on post-Independence religious conflict in India. British colonialism has often been blamed for the worsening of Hindu-Muslim relations. Comparing districts ruled by native kings with districts which were ruled directly by the British, I find no adverse effect of British colonialism. The third research chapter looks at the evolution of the economic conditions of Muslims in the last three decades-a period which has been characterized by rapid economic growth in India. I compare Muslims with non-Muslims in education, occupation choice, wages and consumption expenditure. I find that Muslims are worse off compared to non-Muslims and this relative deprivation gets more acute over time.
Processes by which relationships shape responses to sexual assault disclosures
Creators: name: Kendrick, Kristin Carol
Publisher: name: University of British Columbia
Year: 2015

description: Sexual assault is a common experience. When survivors disclose their assaults they are more likely to tell their peers than formal support providers. Peers’ responses have been found to relate to survivors’ healing processes. Increased understanding regarding why peers respond as they do provides greater opportunities to influence their responses to survivors through outreach and support work. Previous research largely overlooks how the peer-survivor relationship might relate to responses to disclosures of sexual assault. This research includes both formal and informal supporters to increase the range of relationships available for examination. Two studies were conducted. The first study surveyed undergraduate students to investigate associations between different aspects of peer relationships and: a) emotional distress experienced after a disclosure, and b) social reactions provided to the survivor. The second study interviewed a subset of the peers involved in Study 1 as well as counsellors and support workers. Qualitative content analysis of interviews was used to increase understanding about the processes by which responses to disclosures of sexual assault are shaped by relationship characteristics. Findings suggest that relationship characteristics and type matter in disclosures of sexual assault. This dissertation advances research about sexual assault disclosures in three important ways. First, it contributes to understanding about divergent social reactions to sexual assault disclosures by including a wide range of relationships at the time of disclosure, ranging from no prior relationship to close friendships. Second, it examines various supporters’ perspectives of how their thoughts and emotions might relate to their reactions to survivors. Little research has investigated a range of supporters’ views of why they react in the ways they do. Third, this dissertation contributes to knowledge about how to improve support to survivors and the people to whom they disclose. Without better understanding of how supporters’ experiences relate to their responses, working with peers and formal supporters to help them respond in more helpful ways is difficult. Results are discussed in terms of their implications for prevention and intervention efforts and recommendations for systems of support.
Reduced-Reference Quality Assessment of Point Clouds via Content-Oriented Saliency Projection
Creators: name: Zhou, Wei
name: Yue, Guanghui
name: Zhang, Ruizeng
name: Qin, Yipeng
name: Liu, Hantao
Publisher: name: arXiv
Year: 2023
Subjects: subject: Multimedia (cs.MM)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Many dense 3D point clouds have been exploited to represent visual objects instead of traditional images or videos. To evaluate the perceptual quality of various point clouds, in this letter, we propose a novel and efficient Reduced-Reference quality metric for point clouds, which is based on Content-oriented sAliency Projection (RR-CAP). Specifically, we make the first attempt to simplify reference and distorted point clouds into projected saliency maps with a downsampling operation. Through this process, we tackle the issue of transmitting large-volume original point clouds to user-ends for quality assessment. Then, motivated by the characteristics of the human visual system (HVS), the objective quality scores of distorted point clouds are produced by combining content-oriented similarity and statistical correlation measurements. Finally, extensive experiments are conducted on SJTU-PCQA and WPC databases. The experimental results demonstrate that our proposed algorithm outperforms existing reduced-reference and no-reference quality metrics, and significantly reduces the performance gap between state-of-the-art full-reference quality assessment methods. In addition, we show the performance variation of each proposed technical component by ablation tests.
Constructing non-compact operators into $c_0$
Creators: name: Banakh, Iryna
name: Banakh, Taras
Publisher: name: arXiv
Year: 2010
Subjects: subject: Functional Analysis (math.FA)
subject: FOS: Mathematics
subject: 47B07, 46B15

description: We prove that for each dense non-compact linear operator $S:X\to Y$ between Banach spaces there is a linear operator $T:Y\to c_0$ such that the operator $TS:X\to c_0$ is not compact. This generalizes the Josefson-Nissenzweig Theorem.
description: 2 pages
Spin polarized electric currents in semiconductor heterostructures induced by microwave radiation
Creators: name: Drexler, C.
name: Bel'kov, V. V.
name: Ashkinadze, B.
name: Olbrich, P.
name: Zoth, C.
name: Lechner, V.
name: Terent'ev, Ya. V.
name: Yakovlev, D. R.
name: Karczewski, G.
name: Wojtowicz, T.
name: Schuh, D.
name: Wegscheider, W.
name: Ganichev, S. D.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We report on microwave (mw) radiation induced electric currents in (Cd,Mn)Te/(Cd,Mg)Te and InAs/(In,Ga)As quantum wells subjected to an external in-plane magnetic field. The current generation is attributed to the spin-dependent energy relaxation of electrons heated by mw radiation. The relaxation produces equal and oppositely directed electron flows in the spin-up and spin-down subbands yielding a pure spin current. The Zeeman splitting of the subbands in the magnetic field leads to the conversion of the spin flow into a spin-polarized electric current.
description: 3 pages, 4 figures
Quark-hadron duality at work: lifetimes of bottom baryons
Creators: name: Gratrex, James
name: Lenz, Alexander
name: Melić, Blaženka
name: Nišandžić, Ivan
name: Piscopo, Maria Laura
name: Rusov, Aleksey V.
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: In the 1990s, very low experimental values for the lifetime ratio $τ(Λ_b)/τ(B_d)$ triggered a considerable amount of doubt in the applicability of the heavy quark expansion (HQE), which is based on the assumption of quark-hadron duality (QHD) for inclusive total decay rates. However, these low values turned out to be the result of purely experimental problems, and the current HFLAV average reads $τ(Λ_b)/τ(B_d) = 0.969(6)$. In this work, we present the Standard Model predictions for the $b$-baryon lifetimes within the framework of the HQE. In particular, we include for the first time the contribution of the Darwin term and we update the estimates for the matrix elements of the dimension-six four-quark operators. Within experimental and theoretical uncertainties, we find excellent agreement between the data and the HQE predictions, and thus no indication for any visible violation of QHD. Our numerical results can be summarised by the ratios $τ(Λ_b)/τ(B_d) = 0.955(14)$, $τ(Ω_b^-)/τ(B_d) = 1.081(42)$, and $τ(Ξ_b^0)/τ(Ξ_b^-) = 0.929(28)$.
description: 36 pages, 3 figures, 8 tables
Mixing in classical novae: a 2-D sensitivity study
Creators: name: Casanova, Jordi
name: Jose, Jordi
name: Garcia-Berro, Enrique
name: Calder, Alan
name: Shore, Steven N.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Classical novae are explosive phenomena that take place in stellar binary systems. They are powered by mass transfer from a low-mass, main sequence star onto a white dwarf. The material piles up under degenerate conditions and a thermonuclear runaway ensues. The energy released by the suite of nuclear processes operating at the envelope heats the material up to peak temperatures of ~ (1 - 4) \times 108 K. During these events, about 10-4 - 10-5 M\odot, enriched in CNO and other intermediate-mass elements, are ejected into the interstellar medium. To account for the gross observational properties of classical novae (in particular, a metallicity enhancement in the ejecta above solar values), numerical models assume mixing between the (solar-like) material transferred from the companion and the outermost layers (CO- or ONe-rich) of the underlying white dwarf. The nature of the mixing mechanism that operates at the core-envelope interface has puzzled stellar modelers for about 40 years. Here we investigate the role of Kelvin-Helmholtz instabilities as a natural mechanism for self-enrichment of the accreted envelope with core material. The feasibility of this mechanism is studied by means of the multidimensional code FLASH. Here, we present a series of 9 numerical simulations perfomed in two dimensions aimed at testing the possible influence of the initial perturbation (duration, strength, location, and size), the resolution adopted, or the size of the computational domain on the results. We show that results do not depend substantially on the specific choice of these parameters, demonstrating that Kelvin- Helmholtz instabilities can naturally lead to self-enrichment of the accreted envelope with core material, at levels that agree with observations.
description: Accepted for publication in A&A
Improved methodologies to study the performance of the ANET Compact Neutron Collimator
Creators: name: Sans-Planell, Oriol
name: Cantini, Francesco
name: Costa, Marco
name: Durisi, Elisabetta
name: Grazzi, Francesco
name: Mafucci, Ettore
name: Monti, Valeria
name: Bedogni, Roberto
name: Li, Yueer
name: van Eijck, Lambert
Publisher: name: arXiv
Year: 2023
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: The ANET project aims at developing 2D compact neutron collimators for neutron imaging applications. The results of the ANET collimator performances, presented in this communication, are based on data collected at the FISH beamline at TU-Delft. Two independent methods to evaluate the neutron radiography resolution are described and discussed, as well as a comparison of the beam divergence with or without the ANET collimator.
description: 11 pages, 9 figures
Discussion of "Statistical Inference: The Big Picture" by R. E. Kass
Creators: name: Goodman, Steven N.
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-STS337A the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Essays on econometrics
Creators: name: Yu, Zhengfei
Publisher: name: University of British Columbia
Year: 2015

description: This thesis studies two topics in Econometric models, multiple equilibria and weak instruments. Chapter 1 is an introduction. Chapter 2 considers nonparametric structural equations which may have multiple solutions for the endogenous variables. The main finding is that multiple equilibria would reveal itself in the form of jump(s) in the density function of the endogenous variables. When there is a unique equilibrium, the density function of endogenous variables will be continuous, while when there are multiple equilibria, the density will have a jump at some point, under reasonable conditions. Our test statistic is based on maximizing local jumps over the support of endogenous variables and the critical value is computed via a Gaussian multiplier bootstrap. Chapter 3 shows that in games with incomplete information, even when the payoff functions and the latent distributions are all smooth, the observed conditional choice probabilities may have a jump with respect to continuous covariates. This chapter provides a theoretical analysis on the relationship between the equilibrium behaviour of the game and the presence of a jump in the conditional choice probabilities. Such jump(s) matters in empirical research for two reasons. Statistically, it affects the estimation of the conditional choice probabilities. Economically, whether the conditional choice probabilities have a jump or not reveals information about the equilibrium behaviour of the game. Our findings are robust to correlated private information and unobserved heterogeneity independent of covariates. Chapter 4 considers efficient inference for the coefficient of the endogenous variable in linear regression models with weak instrumental variables (Weak-IV). We focus on the power of tests for the alternative hypotheses that are determined by arbitrarily large deviations from the null. We derive the power envelope for such alternatives in the Weak-IV scenario. Then we compare the power properties of popular Weak-IV robust tests, focusing on the Anderson-Rubin (AR) and Conditional Likelihood Ratio (CLR) tests. We find that their relative performance depends on the degree of endogeniety in the model. In addition, we propose a Conditional Lagrange Multiplier (CLM) test. We also extend our analysis to heteroskedastic models.
Angular resolved specific heat in iron-based superconductors: the case for nodeless extended $s$-wave gap
Creators: name: Chubukov, A. V.
name: Eremin, I.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We consider the variation of the field-induced component of the specific heat $C({\bf H})$ with the direction of the applied field in $Fe-$pnictides within quasi-classical Doppler-shift approximation, with special emphasis to recent experiments on FeSe$_{0.4}$Te$_{0.6}$ [Zheng et al., arXiv:1004.2236]. We show that for extended $s-$wave gap with no nodes, $C({\bf H})$ has $\cos 4 ϕ$ component, where $ϕ$ is the angle between ${\bf H}$ and the direction between hole and electron Fermi surfaces. The maxima of $C({\bf H})$ are at $π/4$, $3π/4$, etc. if the applied field is smaller than $H_0 \leq 1T$, and at $ϕ=0, π/2$, etc. if the applied field is larger than $H_0$. The angle-dependence of $C({\bf H})$, the positions of the maxima, and the relative magnitude of the oscillating component are consistent with the experiments performed in the field of $9T >> H_0$. We show that the observed $\cos 4 ϕ$ variation does not hold if the $s-$wave gap has accidental nodes along the two electron Fermi surfaces.
description: 5 pages, 4 figures
Large barrier behaviour of the rate constant from the diffusion equation
Creators: name: Pravatto, Pierpaolo
name: Fresch, Barbara
name: Moro, Giorgio J.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: Soft Condensed Matter (cond-mat.soft)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Many processes in chemistry, physics, and biology depend on thermally activated events in which the system changes its state by surmounting an activation barrier. Examples range from chemical reactions, protein folding, and nucleation events. Parameterized forms of the mean-field potential are often employed in the stochastic modeling of activated processes. In this contribution, we explore the alternative of employing parameterized forms of the equilibrium distribution by means of the symmetric linear combination of two gaussian functions. Such a procedure leads to flexible and convenient models for the landscape and the energy barrier whose features are controlled by the second moments of the gaussian functions. The rate constants are examined through the solution of the corresponding diffusion problem, that is the Fokker-Planck-Smoluchowski equation specified according to the parameterized equilibrium distribution. The numerical calculations clearly show that the asymptotic limit of large barriers does not agree with the results of the Kramers theory. The underlying reason is that the linear scaling of the potential, the procedure justifying the Kramers theory, cannot be applied when dealing with parameterized forms of the equilibrium distribution. A different kind of asymptotic analysis is then required and we introduce the appropriate theory when the equilibrium distribution is represented as a symmetric linear combination of two gaussian functions, first in the one-dimensional case and afterward in the multi-dimensional diffusion model.
Pinyin Regularization in Error Correction for Chinese Speech Recognition with Large Language Models
Creators: name: Tang, Zhiyuan
name: Wang, Dong
name: Huang, Shen
name: Shang, Shidong
Publisher: name: arXiv
Year: 2024
Subjects: subject: Computation and Language (cs.CL)
subject: Sound (cs.SD)
subject: Audio and Speech Processing (eess.AS)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Recent studies have demonstrated the efficacy of large language models (LLMs) in error correction for automatic speech recognition (ASR). However, much of the research focuses on the English language. This paper redirects the attention to Chinese. Firstly, we construct a specialized benchmark dataset aimed at error correction for Chinese ASR with 724K hypotheses-transcription pairs, named the Chinese Hypotheses Paradise dataset (ChineseHP), which contains a wide range of scenarios and presents significant challenges. Subsequently, we conduct a preliminary evaluation using the dataset for both direct-prompting and fine-tuning pre-trained LLMs. Furthermore, we propose a straightforward method of Pinyin regularization for prompts, which involves the transcription of Pinyin directly from text hypotheses. The experimental results reveal that Pinyin regularization consistently enhances the error-correcting ability of LLMs when compared with those without regularization. The dataset is available on the website.
description: Interspeech 2024
Local suppression of the hidden order phase by impurities in URu2Si2
Creators: name: Pezzoli, Maria E.
name: Graf, Matthias J.
name: Haule, Kristjan
name: Kotliar, Gabriel
name: Balatsky, Alexander V.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We consider the effects of impurities on the enigmatic hidden order (HO) state of the heavy-fermion material URu2Si2. In particular, we focus on local effects of Rh impurities as a tool to probe the suppression of the HO state. To study local properties we introduce a lattice free energy, where the time invariant HO order parameter "psi" and local antiferromagnetic (AFM) order parameter M are competing orders. Near each Rh atom the HO order parameter is suppressed, creating a hole in which local AFM order emerges as a result of competition. These local holes are created in the fabric of the HO state like in a Swiss cheese and "filled" with droplets of AFM order. We compare our analysis with recent NMR results on URu2Si2 doped with Rh and find good agreement with the data.
description: 8 pages, 6 figures
The Entropic Uncertainty Principle for Decaying Systems and CP violation
Creators: name: Hiesmayr, Beatrix C.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Employing an effective formalism for decaying system we are able to investigate Heisenberg's uncertainty relation for observables measured at accelerator facilities. In particular we investigate the neutral K--meson system and show that, firstly, due to the time evolution an uncertainty between strangeness measurements at different times is introduced and, secondly, due to the imbalance of matter and antimatter (CP violation) an uncertainty in the evolution of the eigenstates of the effective Hamiltonian of the system. Consequently, the existence of CP violation is linked to uncertainties of observables, i.e. the outcomes cannot be predicted even in principle to arbitrary precisions.
description: 8 pages, 5 figures. To appear in the proceedings of the "Symposium on Prospects in the Physics of Discrete Symmetries", 6-11 December 2010, Rome, Italy
Low-threshold lasing of optically pumped micropillar lasers with Al$_{0.2}$Ga$_{0.8}$As/Al$_{0.9}$Ga$_{0.1}$As distributed Bragg reflectors
Creators: name: Shih, Ching-Wen
name: Limame, Imad
name: Krüger, Sebastian
name: Palekar, Chirag C.
name: Koulas-Simos, Aris
name: Brunner, Daniel
name: Reitzenstein, Stephan
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We report on the design, realization and characterization of optically pumped micropillar lasers with low-absorbing Al$_{0.2}$Ga$_{0.8}$As/Al$_{0.9}$Ga$_{0.1}$As dielectric Bragg reflectors (DBRs) instead of commonly used GaAs/AlGaAs DBRs. A layer of (In, Ga)As quantum dots (QDs) is embedded in the GaAs $λ$-cavity of as an active medium. We experimentally study the lasing characteristics of the fabricated micropillars by means of low-temperature photoluminescence with varying pump laser's wavelength between 532 nm and 899 nm. The incorporation of 20% Al content in the DBRs opens an optical pumping window from 700 nm to 820 nm, where the excitation laser light can effectively reach the GaAs cavity above its bandgap, while remaining transparent to the DBRs. This results in a substantially improved pump efficiency, a low lasing threshold, and a high thermal stability. Pump laser wavelengths outside of the engineered spectral window lead to low pump efficiency due to strong absorption by the top DBR, or inefficient excitation of pump-level excitons, respectively. The superiority of the absorption-free modified DBRs is demonstrated by simply switching the pump laser wavelength from 671 nm to 708 nm, which crosses the DBRs absorption edge and drastically reduces the lasing threshold by more than an order of magnitude from (363.5 $\pm$ 18.5) $μ$W to (12.8 $\pm$ 0.3) $μ$W.
Sedimentary rock hosted copper mineralization in the Neoproterozoic Redstone Copperbelt, Northwest Territories, Canada
Creators: name: Milton, Jack Edward
Publisher: name: University of British Columbia
Year: 2015

description: Physical-chemical fluid evolution, timing of fluid-migration and driving forces for fluid-flow are factors that fundamentally control the mass transport that leads to the formation of sedimentary rock hosted copper deposits. This thesis constrains these factors for Kupferschiefer-type mineralization in a sequence of Neoproterozoic rocks of the Redstone Copperbelt, Mackenzie Mountains, Northwest Territories, Canada. Stratiform copper mineralization is located in rift-basins that formed during the break-up of the supercontinent Rodinia within a period of Earth’s history that witnessed evolution of Precambrian life and dramatic climate changes associated with the Snowball Earth glaciations. A U-Pb zircon date is presented, constraining the eruption of a marker unit within the Neoproterozoic sequence that heralded the prolonged period of rifting that led to supercontinent fragmentation. The age also constrains the deposition of the host rocks for stratiform copper mineralization. Dating monazite grains associated with mineralization at the Coates Lake stratiform copper deposit demonstrates that mineralization occurred ~100 My after host rock deposition, following 2-4 km of burial. Mapping, fluid inclusion, paragenetic, and S-Sr-O-C isotope evidence show that mineralizing fluids were ~190 to 250 °C, had salinities of ~32 wt. % NaCl equivalent, were overpressured and circulated through red-beds that underlie mineralization. Fluid-pathways have been traced through the red-beds, up basin-margin faults and back laterally along stratigraphy in mineralized zones, suggesting that flow was circulatory and evidence is presented for free-convection. Two significant glacial episodes may have produced cryogenic brines that are a potential source of salinity for mineralizing fluids. Modelling the behavior of H-O-Cu-S-Cl over a range of temperature and salinity representative of stratiform copper mineralization suggests that significant solubilities of copper can be attained by even weakly oxidized fluids. This study contributes to a growing body of evidence that Kupferschiefer-type deposits are not only formed during early-diagenesis, but can form after significant periods of burial from saline, moderate temperature fluids that are not highly oxidized. A separate style of ‘vein-vug’ copper mineralization has been dated and occurred later in the basin-history, possibly as remobilization of stratiform mineralization; vein-vug mineralization may have formed in association with regional Zn-Pb mineralization across the northern Canadian Cordillera.