cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Free rational curves on low degree hypersurfaces and the circle method
Creators: name: Browning, Tim
name: Sawin, Will
Publisher: name: arXiv
Year: 2018
Subjects: subject: Algebraic Geometry (math.AG)
subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 14H10 (11D45, 11P55, 14G05, 14J70)

description: We use a function field version of the Hardy-Littlewood circle method to study the locus of free rational curves on an arbitrary smooth projective hypersurface of sufficiently low degree. On the one hand this allows us to bound the dimension of the singular locus of the moduli space of rational curves on such hypersurfaces and, on the other hand, it sheds light on Peyre's reformulation of the Batyrev-Manin conjecture in terms of slopes with respect to the tangent bundle.
description: 34 pages
Autophagy-related protein PIK3C3/VPS34 controls T cell metabolism and function
Creators: name: Yang, Guan
name: Song, Wenqiang
name: Postoak, J. Luke
name: Chen, Jin
name: Martinez, Jennifer
name: Zhang, Jianhua
name: Wu, Lan
name: Van Kaer, Luc
Publisher: name: Taylor & Francis
Year: 2020
Subjects: subject: Biochemistry
subject: Cell Biology
subject: Genetics
subject: FOS: Biological sciences
subject: Neuroscience
subject: Physiology
subject: Immunology
subject: FOS: Clinical medicine
subject: Developmental Biology
subject: Cancer

description: The PIK3C3/VPS34 subunit of the class III phosphatidylinositol 3-kinase (PtdIns3K) complex is a key early player in macroautophagy/autophagy. In this study, we assessed the contribution of PIK3C3 to T cell metabolism and function. We found that Pik3c3-deficient T cells exhibited impaired cellular metabolism, and Pik3c3-deficient CD4+ T cells failed to differentiate into T helper 1 cells. These alterations were associated with reduced levels of active mitochondria upon T cell activation. In addition, conditional Pik3c3-deficient animals failed to mount autoreactive T cell responses and were resistant to experimental autoimmune encephalomyelitis (EAE). Interestingly, the deletion of Pik3c3 had little effect on the capacity of animals to clear tumor metastases. Collectively, our studies have revealed a critical role of PIK3C3 in T cell metabolism and the pathogenicity of these cells during EAE. Our findings also have important implications for the development of immunotherapies to treat multiple sclerosis and other inflammatory diseases by targeting PIK3C3. Abbreviations: CNS: central nervous system; DC: dendritic cell; DEG: differentially expressed gene; EAE: experimental autoimmune encephalomyelitis; ECAR: extracellular acidification rate; iNKT: invariant natural killer T; LAP: LC3-associated phagocytosis; LLC: Lewis lung carcinoma; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MDSC: myeloid-derived suppressor cell; MOG: myelin oligodendrocyte glycoprotein; NK: natural killer; OCR: oxygen consumption rate; PI: propidium iodide; PIK3C3/VPS34: phosphatidylinositol 3-kinase catalytic subunit type 3; RNA-seq: RNA-sequencing; TCR: T cell receptor; TMRE: tetramethylrhodamine ethyl ester perchlorate
Counterterms in semiclassical Horava-Lifshitz gravity
Creators: name: Giribet, Gaston
name: Nacir, Diana López
name: Mazzitelli, Francisco D.
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We analyze the semiclassical Hořava-Lifshitz gravity for quantum scalar fields in 3+1 dimensions. The renormalizability of the theory requires that the action of the scalar field contains terms with six spatial derivatives of the field, i.e. in the UV, the classical action of the scalar field should preserve the anisotropic scaling symmetry ($t \to L^{2z}t,$ $\vec{x} \to L^2 \vec{x}$, with $z=3$) of the gravitational action. We discuss the renormalization procedure based on adiabatic subtraction and dimensional regularization in the weak field approximation. We verify that the divergent terms in the adiabatic expansion of the expectation value of the energy-momentum tensor of the scalar field contain up to six spatial derivatives, but do not contain more than two time derivatives. We compute explicitly the counterterms needed for the renormalization of the theory up to second adiabatic order and evaluate the associated $β$ functions in the minimal subtraction scheme.
description: 8 pages
Quasicontinuous horizontally guided atom laser: coupling spectrum and flux limits
Creators: name: Bernard, Alain
name: Guerin, William
name: Billy, Juliette
name: Jendrzejewski, Fred
name: Cheinet, Patrick
name: Aspect, Alain
name: Josse, Vincent
name: Bouyer, Philippe
Publisher: name: arXiv
Year: 2010
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: We study in detail the flux properties of a radiofrequency outcoupled horizontally guided atom laser, following the scheme demonstrated in [Guerin W et al. 2006 Phys. Rev. Lett. 97 200402]. Both the outcoupling spectrum (flux of the atom laser versus rf frequency of the outcoupler) and the flux limitations imposed to operate in the quasicontinuous regime are investigated. These aspects are studied using a quasi-1D model, whose predictions are shown to be in fair agreement with the experimental observations. This work allows us to identify the operating range of the guided atom laser and to confirm its good promises in view of studying quantum transport phenomena.
KAM Hamiltonians are not Quantum Ergodic
Creators: name: Gomes, Sean
Publisher: name: arXiv
Year: 2018
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: We show that under generic conditions, the quantisation of a $1$-parameter family of KAM perturbations $P(x,ξ;t)$ of a completely integrable and Kolmogorov non-degenerate Gevrey smooth Hamiltonian is not quantum ergodic, at least for a full measure subset of the parameter $t\in (0,δ)$.
description: arXiv admin note: substantial text overlap with arXiv:1709.09919
You need to get into their space : a qualitative study of the Moe the Mouse ™ program
Creators: name: Donovan, James
Publisher: name: University of British Columbia
Year: 2015

description: Early education programs for preschoolers often have a greater impact on language and literacy outcomes than those offered later on (Ball, 2007; Canadian Council on Learning, 2007; Gerlach & Zeidler, 2004; Townsend & Konold, 2010), particularly when the programs are strengths based, culturally attuned, and relationships focused. Moe the Mouse ™ is one such program, addressing early speech, language and preliteracy skills within a culturally relevant framework for preschoolers with Aboriginal backgrounds. To date, there has been little empirical research on the Moe the Mouse ™ program. The current study sought to explore the perspectives of people who use or support the program through focus group discussions and qualitative analyses as one step in evaluation of the program. Methodology: Sixteen practitioners who used or supported the Moe the Mouse ™ program were recruited through a local community centre to give their perspectives on the program in focus group discussions. Three of the groups met just after they received training on the program, and the fourth group, six months later. Using qualitative methodology, participants’ audio-recorded discussions were transcribed and sorted into broad thematic categories, allowing a discovery of themes important to participants. Results: Within the broad topics of culturally relevant curricula and perspectives on Moe the Mouse ™, two major themes emerged from the participants’ discussions. These themes included (1) supporting a child’s identity through adaptable and engaging programs, and (2) building a diverse and capable team from all aspects of a child’s community. Discussion: The emergent themes of supporting children’s identities and relationship building contextualize the Moe the Mouse ™ program as one that is strengths-based, culturally relevant and relationship building. The themes also reflect the need to individualize a program within a playful and engaging group context. In early childhood education, there is a need to support Aboriginal communities in self-determination, cultural programming, and intergenerational healing through cultivating relationships and exploring strategies that practitioners and families can use. From the participant’ points of view, Moe the Mouse ™ approaches these broad goals.
A fibration theorem for collapsing sequences of Alexandrov spaces
Creators: name: Fujioka, Tadashi
Publisher: name: arXiv
Year: 2019
Subjects: subject: Differential Geometry (math.DG)
subject: Metric Geometry (math.MG)
subject: FOS: Mathematics
subject: 53C20, 53C23

description: Suppose a sequence $M_j$ of Alexandrov spaces collapses to a space $X$ with only weak singularities. Yamaguchi constructed a map $f_j:M_j\to X$ called an almost Lipschitz submersion for large $j$. We prove that if $M_j$ has a uniform positive lower bound for the volumes of spaces of directions, which is sufficiently large compared to the weakness of singularities of $X$, then $f_j$ is a locally trivial fibration. Moreover, we show some properties on the intrinsic metric and the volume of the fibers of $f_j$.
description: minor changes, to appear in J. Topol. Anal
Connectivity-based parcellation of putamen region using resting state fMRI
Creators: name: Zhang, Yiming
Publisher: name: University of British Columbia
Year: 2015

description: Functional magnetic resonance imaging (fMRI) has shown great potential in studying the underlying neural systems. Functional connectivity measured by fMRI provides an efficient approach to study the interactions and relationships between different brain regions. However, functional connectivity studies require accurate definition of brain regions, which is often difficult and may not be achieved through anatomical landmarks. In this thesis, we present a novel framework for parcellation of a brain region into functional subunits based on their connectivity patterns with other reference brain regions. The proposed method takes the prior neurological information into consideration and aims at finding spatially continuous and functionally consistent sub-regions in a given brain region. The proposed framework relies on a sparse spatially regularized fused lasso regression model for feature extraction. The usual lasso model is a linear regression model commonly applied in high dimensional data such as fMRI signals. Compared with lasso, the proposed model further considers the spatial order of each voxel and thus encourages spatially and functionally adjacent voxels to share similar regression coefficients despite of the possible spatial noise. In order to achieve the accurate parcellation results, we propose a process by iteratively merging voxels (groups) and tuning the parameters adaptively. In addition, a Graph-Cut optimization algorithm is adopted for assigning the overlapped voxels into separate sub-regions. With spatial information incorporated, spatially continuous and functionally consistent subunits can be obtained which are desired for subsequent brain connectivity analysis. The simulation results demonstrate that the proposed method could reliably yield spatially continuous and functionally consistent subunits. When applied to real resting state fMRI datasets, two consistent functional subunits could be obtained in the putamen region for all normal subjects. Comparisons between the results of the Parkinson’s disease group and the normal group suggest that the obtained results are in accordance with our medical assumption. The extracted functional subunits themselves are of great interest in studying the influence of aging and a certain disease, and they may provide us deeper insights and serve as a biomarker in our future Parkinson’s disease study.
Nonlinear light localization around the core of a `holey' fiber
Creators: name: Bennet, Francis H.
name: Molina, Mario I.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Pattern Formation and Solitons (nlin.PS)
subject: FOS: Physical sciences

description: We examine localized surface modes in the core of a photonic crystal fiber composed of a finite nonlinear (Kerr) hexagonal waveguide array with a central defect. Using a discrete approach, we find the fundamental surface mode and its stability window. We also examine an unstaggered, ring-shaped surface mode and find that it is always unstable, decaying to the single-site fundamental surface mode. A continuous model computation reveals that an initial vortex excitation (S=1) of small amplitude around the central hole can survive for a relatively long evolution distance. At high amplitudes, however, it decays to a ring configuration with no well-defined phase structure.
description: five double-column pages, seven figures, submitted for publication
Rotational Bands and Electromagnetic Transitions of some even-even Neodymium Nuclei in J-Projected Hartree-Fock Model
Creators: name: Ghorui, S. K.
name: Naik, Z.
name: Patra, S. K.
name: Singh, A. K.
name: Raina, P. K.
name: Rath, P. K.
name: Praharaj, C. R.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: Rotational structures of even-even $^{148-160}$Nd nuclei are studied with the self-consistent deformed Hartree-Fock (HF) and angular momentum (J) projection model. Spectra of ground band, recently observed $K=4^{-}$, $K=5^{-}$ and a few more excited, positive and negative parity bands have been studied upto high spin values. Apart from these detailed electromagnetic properties (like E2, M1 matrix elements) of all the bands have been obtained. There is substantial agreement between our model calculations and available experimental data. Predictions are made about the band structures and electromagnetic properties of these nuclei. Some 4-qasiparticle K-isomeric bands and their electromagnetic properties are predicted.
description: 20 pages
Additional file 3 of Proteome evaluation of homolog abundance patterns in Arachis hypogaea cv. Tifrunner
Creators: name: Duan, Zhenquan
name: Zhang, Yongli
name: Zhang, Tian
name: Chen, Mingwei
name: Song, Hui
Publisher: name: figshare
Year: 2022
Subjects: subject: Genetics
subject: FOS: Biological sciences

description: Additional file 3: Fig. S3. The gene ontology enrichment of biased homeologs in the leaf sub-genome B.
A comment on "Amplification of endpoint structure for new particle mass measurement at the LHC"
Creators: name: Barr, A. J.
name: Gwenlan, C.
name: Lester, C. G.
name: Young, C. J. S.
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We present a comment on the kinematic variable $m_{CT2}$ recently proposed in "Amplification of endpoint structure for new particle mass measurement at the LHC". The variable is designed to be applied to models such as R-parity conserving Supersymmetry (SUSY) when there is pair production of new heavy particles each of which decays to a single massless visible and a massive invisible component. It was proposed in "Amplification of endpoint structure for new particle mass measurement at the LHC" that a measurement of the peak of the $m_{CT2}$ distribution could be used to precisely constrain the masses of the SUSY particles. We show that when Standard Model backgrounds are included in simulations, the sensitivity of the $m_{CT2}$ variable to the SUSY particle masses is more seriously impacted for $m_{CT2}$ than for other previously proposed variables.
description: 5 pages
Products and connected sums of spheres as monotone Lagrangian submanifolds
Creators: name: Oganesyan, Vardan
name: Sun, Yuhan
Publisher: name: arXiv
Year: 2019
Subjects: subject: Symplectic Geometry (math.SG)
subject: FOS: Mathematics

description: We obtain new restrictions on Maslov classes of monotone Lagrangian submanifolds of $\mathbb{C}^n$. We also construct families of new examples of monotone Lagrangian submanifolds, which show that the restrictions on Maslov classes are sharp in certain cases.
description: 18 pages, clarified and simplified. arXiv admin note: text overlap with arXiv:1812.05007
Extremely high reflection of solar wind protons as neutral hydrogen atoms from regolith in space
Creators: name: Wieser, Martin
name: Barabash, Stas
name: Futaana, Yoshifumi
name: Holmström, Mats
name: Bhardwaj, Anil
name: Sridharan, R
name: Dhanya, MB
name: Wurz, Peter
name: Schaufelberger, Audrey
name: Asamura, Kazushi
Publisher: name: arXiv
Year: 2010
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Plasma Physics (physics.plasm-ph)
subject: Space Physics (physics.space-ph)
subject: FOS: Physical sciences

description: We report on measurements of extremely high reflection rates of solar wind particles from regolith-covered lunar surfaces. Measurements by the Sub-keV Atom Reflecting Analyzer (SARA) instrument on the Indian Chandrayaan-1 spacecraft in orbit around the Moon show that up to 20% of the impinging solar wind protons are reflected from the lunar surface back to space as neutral hydrogen atoms. This finding, generally applicable to regolith-covered atmosphereless bodies, invalidates the widely accepted assumption that regolith almost completely absorbs the impinging solar wind.
description: 2 figures
Wandering domains arising from Lavaurs maps with Siegel disks
Creators: name: Matthieu, Astorg
name: Luka, Boc Thaler
name: Han, Peters
Publisher: name: arXiv
Year: 2019
Subjects: subject: Dynamical Systems (math.DS)
subject: Complex Variables (math.CV)
subject: FOS: Mathematics

description: The classification of Fatou components for rational functions was concluded with Sullivan's proof of the No Wandering Domains Theorem in 1985. In 2016 it was shown, in joint work of the first and last author with Buff, Dujardin and Raissy, that wandering domains do exist in higher dimensions. In fact, wandering domains arise even for a seemingly simple class of maps: polynomial skew products. While the construction gives an infinite dimensional class of examples, and has been extended to polynomial automorphisms of $\mathbb C^4$ by Hahn and the last author, the currently known wandering domains are essentially unique. Our goal in this paper is to construct a second example, arising from similar techniques, but with distinctly different dynamical behavior. Instead of wandering domains arising from a Lavaurs map with an attracting fixed point, we construct a domain arising from a Lavaurs map with a fixed point of Siegel type. Siegel disks are not robust under perturbations, as opposed to attracting fixed points. We prove a necessary and sufficient condition for the existence of a so-called trapping domain for non-autonomous dynamical systems given by sequences of maps converging parabolically towards a Siegel type limit map. Guaranteeing that this condition is satisfied in our current construction requires a reconsideration of the proof of the original wandering domain, as more precise estimates on the rate of convergence towards the Lavaurs map are required. By adapting ideas introduced recently by Bedford, Smillie and Ueda, and by proving the existence of parabolic curves, with control on their domains of definition, we prove that the convergence rate is parabolic.
description: 54 pages, 2 figures
Optimal Lifting for the Projective Action of $SL_3(Z)$
Creators: name: Kamber, Amitay
name: Lavner, Hagai
Publisher: name: arXiv
Year: 2019
Subjects: subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 11F06

description: Let $ε>0$ and let $q$ be a prime going to infinity. We prove that with high probability given $x,y$ in the projective plane over the finite field $F_q$ there exists $γ$ in $SL_3(Z)$, with coordinates bounded by $q^{1/3+ε}$, whose projection to $SL_{3}(F_q)$ sends $x$ to $y$. The exponent $1/3$ is optimal and the result is a high rank generalization of Sarnak's optimal strong approximation theorem for $SL_2(Z)$.
description: 24 pages. Major revision. Added a proof of the simpler case of SL2, rewrote the proof of Theorem 1.4, added a theorem about optimal lifting for the action on flags
Implementing distancing in case of school reopening amid COVID-19 pandemic: Recommendations
Creators: name: Askarian, Mehrdad
name: Taghrir, Mohammad Hossein
name: Estedlal, Alireza
name: Estedlal, Taraneh
name: Tabei, Seyed Sajjad
name: Askarian, Ardalan
Publisher: name: IfADo - Leibniz Research Centre for Working Environment and Human Factors, Dortmund
Year: 2021
Subjects: school health
COVID-19
reopening
public health

description: EXCLI Journal; 20:Doc1407; ISSN 1611-2156
The Fundamental Plane of Early-Type Galaxies as a Confounding Correlation
Creators: name: Fraix-Burnet, Didier
Publisher: name: arXiv
Year: 2011
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Early-type galaxies are characterized by many scaling relations. One of them, the so-called fundamental plane is a relatively tight correlation between three variables, and has resisted a clear physical understanding despite many years of intensive research. Here, we show that the correlation between the three variables of the fundamental plane can be the artifact of the effect of another parameter influencing all, so that the fundamental plane may be understood as a confounding correlation. Indeed, the complexity of the physics of galaxies and of their evolution suggests that the main confounding parameter must be related to the level of diversification reached by the galaxies. Consequently, many scaling relations for galaxies are probably evolutionary correlations.
Quantitative reduction theory and unlikely intersections
Creators: name: Daw, Christopher
name: Orr, Martin
Publisher: name: arXiv
Year: 2019
Subjects: subject: Number Theory (math.NT)
subject: Algebraic Geometry (math.AG)
subject: Logic (math.LO)
subject: FOS: Mathematics
subject: 11F06, 11G18

description: We prove quantitative versions of Borel and Harish-Chandra's theorems on reduction theory for arithmetic groups. Firstly, we obtain polynomial bounds on the lengths of reduced integral vectors in any rational representation of a reductive group. Secondly, we obtain polynomial bounds in the construction of fundamental sets for arithmetic subgroups of reductive groups, as the latter vary in a real conjugacy class of subgroups of a fixed reductive group. Our results allow us to apply the Pila--Zannier strategy to the Zilber--Pink conjecture for the moduli space of principally polarised abelian surfaces. Building on our previous paper, we prove this conjecture under a Galois orbits hypothesis. Finally, we establish the Galois orbits hypothesis for points corresponding to abelian surfaces with quaternionic multiplication, under certain geometric conditions.
description: 44 pages, small corrections and link to online publication in IMRN
Factor Structure of the Young Schema Questionnaire (Long Form‐3)
Creators: name: Yalcin, Ozgur
name: Lee, Christopher
name: Correia, Helen
Publisher: name: Taylor & Francis
Year: 2021
Subjects: Medicine
Biological Sciences not elsewhere classified
Science Policy
Hematology

description: The aim of this study was to assess the factor structure of the English version of the Young Schema Questionnaire Long Form‐3 (YSQ‐L3) using a large clinical sample and smaller non‐clinical population. The items in the YSQ‐L3 were evaluated as to how well they assess the underlying theoretical constructs of schema and schema domains. A primary and a higher order factor (HOF) analysis was undertaken on a large heterogeneous clinical sample (N = 574) and the total sample (N = 838) that included a small non‐clinical population (N = 264). The primary factor analysis revealed 20 early maladaptive schemas (EMS). Of the 232 items, 182 loaded above .4 and were retained for the final analysis. The original Emotional Inhibition schema separated into Emotional Constriction and Fear of Losing Control, and Punitiveness likewise separated into Punitiveness (Self) and Punitiveness (Other). The HOF analysis indicated four domains: Emotional Dysregulation, Disconnection, Impaired Autonomy/Underdeveloped Self, and Excessive Responsibility/Overcontrol. These overlap with the domains proposed by Young et al. (2003) but with some differences. The Emotion Dysregulation domain was unique to the current study. The mean item loading for each factor ranged from .52 to .82. The revised scale showed excellent overall internal consistency (a = .91). This is the first study that investigated the psychometric properties of the English version of the YSQ‐L3. The resultant domains fitted with existing literature of meaningful clinical phenomenon such as attachment and emotion dysregulation and their role in maintaining chronic psychological disorders.
Chiral Gauge Theories on $R^3 \times S^1$ and SUSY Breaking
Creators: name: Lee, Jun Seok
name: Terning, John
Publisher: name: arXiv
Year: 2019
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study SU(5) chiral gauge theories on $R^3\times S^1$. With an unequal number of fundamental and antifundmental matter representations we calculate nontrivial pre-ADS superpotentials generated by composite multi-monopoles. We also point out that the structure of the composite multi-monopoles can be determined simply from the affine Dynkin diagrams of the gauge group and its unbroken subgroup. For the case of one flavor, we find that the superpotential is independent of the composite meson. We show that dynamical 4D SUSY breaking in the simplest chiral SU(5) gauge theory can be demonstrated directly via semi-classical effects on the circle.
description: 28 pages plus 17 pages of appendices
Non-magnetic Stern-Gerlach Experiment from Electron Diffraction
Creators: name: Chern, Chyh-Hong
name: Lin, Cheng-Ju
Publisher: name: arXiv
Year: 2010
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Using the wave nature of the electrons, we demonstrate that a transverse spin current can be generated simply by the diffraction through a single slit in the spin-orbital coupling system of the two-dimensional electron gas. The diffracted electron picks up the transverse momentum. The up spin electron goes one way and the down spin electron goes the other, producing the coherent spin current. In the system of spin-orbital coupling $\sim10^{-13}$ eV$\cdot$m, the \emph{out-of-plane} component of the spin of the electron can be generated up to 0.42 $\hbar$. Based on this effect, a novel device of grating to distill spin is designed. Two first diffraction peaks of electron carry different spins, duplicating the non-magnetic version of Stern-Gerlach experiment. The direction of the spin current can be controlled by the gate voltage with low energy cost.
description: 4 pages, 4 figures
Re/narrating youth : a critical qualitative study of learning in an activist organization
Creators: name: Goessling, Kristen Parker
Publisher: name: University of British Columbia
Year: 2015

description: This critical qualitative research investigated the meaning making practices of a group of 10 youth activists in a youth-driven social justice organization, called Think Again, located in Vancouver, BC. An overarching goal of this study was to contribute to scholarship concerned with how young people, as cultural producers, re/narrate what it means to be a young person in a neoliberal society. To this end, I explored the ways in which contemporary youth narratives, such as the “millennial youth” narrative, afford and constrain learning opportunities for specific groups of young people. My research questions were as follows: (1) In what ways can Think Again be described as a community of practice?; (2) What forms of participation are encouraged at Think Again?; (3) How does youths’ participation at Think Again support and/or challenge the broader social narratives of youth? and; (4) How do participants narrate their lived experiences and participation at Think Again? These questions allowed me to explore the potential disconnect between contemporary youth narratives and youths’ activist narratives to better understand how youths perceive of themselves and their lives within an evolving community of practice (Lave & Wenger, 1991). Analysis of the qualitative data was conducted at three levels in order to identify and examine: (1) narratives across the data, (2) traces of participation across youths’ constructions of knowing, being, and valuing, and (3) participation as future-making. This study resulted in four key findings. The first is a set of more nuanced counternarratives of what it means to be a “youth” today. The second attends to how thinking about learning as participation, a holistic endeavor, also entails changes in knowing, being, and valuing. The third outlines local opportunities for youth participation that generate the conditions for a “politics of possibility” (Holland & Gómez, 2013) as essential to personal and social transformation. The fourth addresses the changing face of youth activism in the contemporary neoliberal context. This study advances the fields of youth engagement, learning as participation, and qualitative methodologies by deploying narrative accounts of young people’s lived experiences.
Network games with dynamic players: Stabilization and output convergence to Nash equilibrium
Creators: name: Guo, Meichen
name: De Persis, Claudio
Publisher: name: arXiv
Year: 2019
Subjects: subject: Optimization and Control (math.OC)
subject: Systems and Control (eess.SY)
subject: FOS: Mathematics
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: This paper addresses a class of network games played by dynamic agents using their outputs. Unlike most existing related works, the Nash equilibrium in this work is defined by functions of agent outputs instead of full agent states, which allows the agents to have more general and heterogeneous dynamics and maintain some privacy of their local states. The concerned network game is formulated with agents modeled by uncertain linear systems subject to external disturbances. The cost function of each agent is a linear quadratic function depending on the outputs of its own and its neighbors in the underlying graph. The main challenge stemming from this game formulation is that merely driving the agent outputs to the Nash equilibrium does not guarantee the stability of the agent dynamics. Using local output and the outputs from the neighbors of each agent, we aim at designing game strategies that achieve output Nash equilibrium seeking and stabilization of the closed-loop dynamics. Particularly, when each agents knows how the actions of its neighbors affect its cost function, a game strategy is developed for network games with digraph topology. When each agent is also allowed to exchange part of its compensator state, a distributed strategy can be designed for networks with connected undirected graphs or connected digraphs.
A test of time-dependent theories of stellar convection
Creators: name: Gastine, T.
name: Dintrans, B.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Context: In Cepheids close to the red edge of the classical instability strip, a coupling occurs between the acoustic oscillations and the convective motions close to the surface.The best topical models that account for this coupling rely on 1-D time-dependent convection (TDC) formulations. However, their intrinsic weakness comes from the large number of unconstrained free parameters entering in the description of turbulent convection. Aims: We compare two widely used TDC models with the first two-dimensional nonlinear direct numerical simulations (DNS) of the convection-pulsation coupling in which the acoustic oscillations are self-sustained by the kappa-mechanism. Methods: The free parameters appearing in the Stellingwerf and Kuhfuss TDC recipes are constrained using a chi2-test with the time-dependent convective flux that evolves in nonlinear simulations of highly-compressible convection with kappa-mechanism. Results: This work emphasises some inherent limits of TDC models, that is, the temporal variability and non-universality of their free parameters. More importantly, within these limits, Stellingwerf's formalism is found to give better spatial and temporal agreements with the nonlinear simulation than Kuhfuss's one. It may therefore be preferred in 1-D TDC hydrocodes or stellar evolution codes.
description: 7 pages, 5 figures, 2 tables, accepted for publication in A&A
Gaussian analytic functions of bounded mean oscillation
Creators: name: Nishry, Alon
name: Paquette, Elliot
Publisher: name: arXiv
Year: 2020
Subjects: subject: Complex Variables (math.CV)
subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 30B20 (Primary), 30H35, 47B80 (Secondary)

description: We consider random analytic functions given by a Taylor series with independent, centered complex Gaussian coefficients. We give a new sufficient condition for such a function to have bounded mean oscillations. Under a mild regularity assumption this condition is optimal. Using a theorem of Holland and Walsh, we give as a corollary a new bound for the norm of a random Gaussian Hankel matrix. Finally, we construct some exceptional Gaussian analytic functions which in particular disprove the conjecture that a random analytic function with bounded mean oscillations always has vanishing mean oscillations.
description: 33 pages
Vertex cut of a graph and connectivity of its neighbourhood complex
Creators: name: Santhanam, Rekha
name: Shukla, Samir
Publisher: name: arXiv
Year: 2020
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics

description: We show that if a graph $G$ satisfies certain conditions then the connectivity of neighbourhood complex $\mathcal{N}(G)$ is strictly less than the vertex connectivity of $G$. As an application, we give a relation between the connectivity of the neighbourhood complex and the vertex connectivity for stiff chordal graphs, and for weakly triangulated graphs satisfying certain properties. Further, we prove that for a graph $G$ if there exists a vertex $v$ satisfying the property that for any $k$-subset $S$ of neighbours of $v$, there exists a vertex $v_S \neq v$ such that $S$ is subset of neighbours of $v_S$, then $\mathcal{N}(G-\{v\})$ is $(k-1)$-connected implies that $\mathcal{N}(G)$ is $(k-1)$-connected. As a consequence of this, we show that:(i) neighbourhood complexes of queen and king graphs are simply connected and (ii) if $G$ is a $(n+1)$-connected chordal graph which is not folded onto a clique of size $n+2$, then $\mathcal{N}(G)$ is $n$-connected.
description: Accepted journal version. Incorporated referee's comments. In section 6, an example of a class of graphs is added, where the connectivity of its neighborhood complex can be made arbitrary large from its vertex connectivity
Cold Dark Matter Isocurvature Perturbations: Cosmological Constraints and Applications
Creators: name: Li, Hong
name: Liu, Jie
name: Xia, Jun-Qing
name: Cai, Yi-Fu
Publisher: name: arXiv
Year: 2010
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: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this paper we present the constraints on cold dark matter (CDM) isocurvature contributions to the cosmological perturbations. By employing Markov Chain Monte Carlo method (MCMC), we perform a global analysis for cosmological parameters using the latest astronomical data, such as 7-year Wilkinson Microwave Anisotropy Probe (WMAP7) observations, matter power spectrum from the Sloan Digital Sky Survey (SDSS) luminous red galaxies (LRG), and "Union2" type Ia Supernovae (SNIa) sample. We find that the correlated mixture of adiabatic and isocurvature modes are mildly better fitting to the current data than the pure adiabatic ones, with the minimal $χ^2$ given by the likelihood analysis being reduced by 3.5. We also obtain a tight limit on the fraction of the CDM isocurvature contributions, which should be less than 14.6% at 95% confidence level. With the presence of the isocurvature modes, the adiabatic spectral index becomes slightly bigger, n_s^{\rm adi}=0.972\pm0.014~(1\,σ), and the tilt for isocurvature spectrum could be large, namely, the best fit value is n_s^{\rm iso}=3.020. Finally, we discuss the effect on WMAP normalization priors, shift parameter R, acoustic scale l_A and z_{*}, from the CDM isocurvaure perturbation. By fitting the mixed initial condition to the combined data, we find the mean values of R, l_A and z_{*} can be changed about 2.9σ, 2.8σand 1.5σrespectively, comparing with those obtained in the pure adiabatic condition.
description: 9 pages, 5 figures, 3 tables, references added
Slow Conductance Relaxation in Insulating Granular Al: Evidence for Screening Effects
Creators: name: Delahaye, Julien
name: Honoré, Jean
name: Grenet, Thierry
Publisher: name: arXiv
Year: 2011
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: It is shown that the conductance relaxations observed in electrical field effect measurements on granular Al films are the sum of two contributions. One is sensitive to gate voltage changes and gives the already reported anomalous electrical field effect. The other one is independent of the gate voltage history and starts when the films are cooled down to low temperature. Their relative amplitude is strongly thickness dependent which demonstrates the existence of a finite screening length in our insulating films and allows its quantitative estimate (about 10nm at 4K). This metallic-like screening should be taken into account in the electron glass models of disordered insulators.
Geometric rank of tensors and subrank of matrix multiplication
Creators: name: Kopparty, Swastik
name: Moshkovitz, Guy
name: Zuiddam, Jeroen
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computational Complexity (cs.CC)
subject: Algebraic Geometry (math.AG)
subject: Combinatorics (math.CO)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics
subject: 68Q17, 15A69

description: Motivated by problems in algebraic complexity theory (e.g., matrix multiplication) and extremal combinatorics (e.g., the cap set problem and the sunflower problem), we introduce the geometric rank as a new tool in the study of tensors and hypergraphs. We prove that the geometric rank is an upper bound on the subrank of tensors and the independence number of hypergraphs. We prove that the geometric rank is smaller than the slice rank of Tao, and relate geometric rank to the analytic rank of Gowers and Wolf in an asymptotic fashion. As a first application, we use geometric rank to prove a tight upper bound on the (border) subrank of the matrix multiplication tensors, matching Strassen's well-known lower bound from 1987.
Ultra-deep Spitzer Mid-Infrared Spectroscopy of LIRGs and ULIRGs at z ~ 1-2
Creators: name: Fadda, D.
name: Yan, L.
name: Lagache, G.
name: Sajina, A.
name: Lutz, D.
name: Wuyts, S.
name: Frayer, D. T.
name: Marcillac, D.
name: Floc'h, E. Le
name: Caputi, K.
name: Spoon, H. W. W.
name: Veilleux, S.
name: Blain, A.
name: Helou, G.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We present ultra-deep mid-IR spectra of 48 infrared-luminous galaxies in the GOODS-South field obtained with the InfraRed Spectrograph (IRS) on the Spitzer Space Telescope. These galaxies are selected among faint infrared sources (0.14 - 0.5 mJy at 24 um) in two redshift bins (0.76-1.05 and 1.75-2.4) to sample the major contributors to the cosmic infrared background at the most active epochs. We estimate redshifts for 92% of the sample using PAH and Si absorption features. Only few of these galaxies (5% at z~1 and 12% at z~2) have their total infrared luminosity dominated by emission from AGN. The averaged mid-IR spectra of the z~1 LIRGs and of the z~2 ULIRGs are very similar to the averaged spectrum of local starbursts and HII-like ULIRGs, respectively. We find that 6.2um PAH equivalent widths reach a plateau of ~1 um for L(24 mu) < 1E11 L(sun). At higher luminosities, EW (6.2 mu) anti-correlates with L(24 um). Intriguingly, high-z ULIRGs and SMG lie above the local EW (6.2 um) - L(24 um) relationship suggesting that, at a given luminosity, high-z ULIRGs have AGN contributions to their dust emission lower than those of local counterparts. A quantitative analysis of their morphology shows that most of the luminous IR galaxies have morphologies similar to those of IR-quiet galaxies at the same redshift. All z~2 ULIRGs of our sample are IR-excess BzK galaxies and most of them have L(FIR)/L(1600A) ratios higher than those of starburst galaxies at a given UV slope. The ``IR excess'' (Daddi et al. 2007) is mostly due to strong 7.7 um PAH emission and under-estimation of UV dust extinction. On the basis of the AGN-powered L (6 um) continuum measured directly from the mid-IR spectra, we estimate an average intrinsic X-ray AGN luminosity of L(2-10 keV) = (0.1 +/- 0.6) 1E43 erg/s, a value substantially lower than the prediction by Daddi et al. (2007).
description: 45 pages, 36 figures, 2 tables, accepted for publication on ApJ
A tale of two toolkits, report the third: on the usage and performance of HIVE-COTE v1.0
Creators: name: Bagnall, Anthony
name: Flynn, Michael
name: Large, James
name: Lines, Jason
name: Middlehurst, Matthew
Publisher: name: arXiv
Year: 2020
Subjects: subject: Machine Learning (cs.LG)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: The Hierarchical Vote Collective of Transformation-based Ensembles (HIVE-COTE) is a heterogeneous meta ensemble for time series classification. Since it was first proposed in 2016, the algorithm has undergone some minor changes and there is now a configurable, scalable and easy to use version available in two open source repositories. We present an overview of the latest stable HIVE-COTE, version 1.0, and describe how it differs to the original. We provide a walkthrough guide of how to use the classifier, and conduct extensive experimental evaluation of its predictive performance and resource usage. We compare the performance of HIVE-COTE to three recently proposed algorithms using the aeon toolkit.
Measuring entanglement in condensed matter systems
Creators: name: Cramer, M.
name: Plenio, M. B.
name: Wunderlich, H.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Quantum Physics (quant-ph)
subject: Quantum Gases (cond-mat.quant-gas)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We show how entanglement may be quantified in spin and cold atom many-body systems using standard experimental techniques only. The scheme requires no assumptions on the state in the laboratory and a lower bound to the entanglement can be read off directly from the scattering cross section of Neutrons deflected from solid state samples or the time-of-flight distribution of cold atoms in optical lattices, respectively. This removes a major obstacle which so far has prevented the direct and quantitative experimental study of genuine quantum correlations in many-body systems: The need for a full characterization of the state to quantify the entanglement contained in it. Instead, the scheme presented here relies solely on global measurements that are routinely performed and is versatile enough to accommodate systems and measurements different from the ones we exemplify in this work.
description: 6 pages, 2 figures
Strichartz estimates for mixed homogeneous surfaces in three dimensions
Creators: name: Palle, Ljudevit
Publisher: name: arXiv
Year: 2020
Subjects: subject: Analysis of PDEs (math.AP)
subject: Classical Analysis and ODEs (math.CA)
subject: FOS: Mathematics
subject: 35B45, 42B15

description: We obtain sharp mixed norm Strichartz estimates associated to mixed homogeneous surfaces in $\mathbb{R}^3$. Both cases with and without a damping factor are considered. In the case when a damping factor is considered our results yield a wide generalization of a result of Carbery, Kenig, and Ziesler [CKZ13]. The approach we use is to first classify all possible singularities locally, after which one can tackle the problem by appropriately modifying the methods from the paper of Ginibre and Velo [GV92], and by using the recently developed methods by Ikromov and Müller [IM16].
description: 55 pages
Investigation of quasi-periodic variations in hard X-rays of solar flares. II. Further investigation of oscillating magnetic traps
Creators: name: Jakimiec, J.
name: Tomczak, M.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: In our recent paper (Solar Physics 261, 233) we investigated quasi-periodic oscillations of hard X-rays during impulsive phase of solar flares. We have come to conclusion that they are caused by magnetosonic oscillations of magnetic traps within the volume of hard-X-ray (HXR) loop-top sources. In the present paper we investigate four flares which show clear quasi-periodic sequences of HXR pulses. We also describe our phenomenological model of oscillating magnetic traps to show that it can explain observed properties of HXR oscillations. Main results are the following: 1. We have found that low-amplitude quasi-periodic oscillations occur before impulsive phase of some flares. 2. We have found that quasi-period of the oscillations can change in some flares. We interpret this as being due to changes of the length of oscillating magnetic traps. 3. During impulsive phase a significant part of the energy of accelerated (non-thermal) electrons is deposited within the HXR loop-top source. 4. Our analysis suggests that quick development of impulsive phase is due to feedback between pulses of the pressure of accelerated electrons and the amplitude of magnetic-trap oscillation. 5. We have also determined electron number density and magnetic filed strength for HXR loop-top sources of several flares. The values fall within the limits of $N \approx (2 -15) \times 10^{10}$ cm$^{-3}$, $B \approx (45 - 130)$ gauss.
description: 18 pages, 14 figures, submitted to Solar Physics
Hypoelliptic and spectral estimates for the linearized Landau operator
Creators: name: Rachid, Mohamad
Publisher: name: arXiv
Year: 2020
Subjects: subject: Analysis of PDEs (math.AP)
subject: Mathematical Physics (math-ph)
subject: Functional Analysis (math.FA)
subject: Spectral Theory (math.SP)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: We are interested in the inhomogeneous Landau equation which describes the evolution of a particle density f = f (t, x, v) representing at time t $\ge$ 0, the density of particles at position x $\in$ R 3 and velocity v $\in$ R 3. The study is motivated by the linearization of the Landau equation near Maxwellian distribution. In this article, we establish hypoelliptic estimates, a localization of the spectrum and estimates of the resolvent of the linear Landau operator with hard potentials and Maxwellian molecules. The proof is based on a multiplier method and requires fine pseudo-differential calculus tools.
description: arXiv admin note: text overlap with arXiv:1003.3265 by other authors