cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Instability for Axisymmetric Blow-up Solutions to Incompressible Euler Equations
Creators: name: Lafleche, Laurent
name: Vasseur, Alexis F.
name: Vishik, Misha
Publisher: name: arXiv
Year: 2020
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 76B03, 35B35, 35B44

description: It is still not known whether a solution to the incompressible Euler equation, endowed with a smooth initial value, can blow-up in finite time. In [{\em Comm. Math. Phys.}, 378:557--568, 2020] it has been shown that, if it exists, such a solution becomes linearly unstable close to the blow-up time. In this paper, we show that the same phenomenon holds even in the more rigid axisymmetric case. To obtain this result, we first prove a blow-up criterion involving only the toroidal component of the vorticity. The instability of blow-up profiles is also investigated.
description: 14 pages
All-fiber spatiotemporally mode-locked laser with multimode fiber-based filtering
Creators: name: Teğin, Uğur
name: Rahmani, Babak
name: Kakkava, Eirini
name: Psaltis, Demetri
name: Moser, Christophe
Publisher: name: arXiv
Year: 2020
Subjects: subject: Optics (physics.optics)
subject: Pattern Formation and Solitons (nlin.PS)
subject: FOS: Physical sciences

description: We demonstrate the first multimode fiber interference-based filtering in an all-fiber spatiotemporally mode-locked laser. The oscillator generates dissipative soliton pulses at 1036 nm with 12 mW average power, 6.24 ps duration and 24.3 MHz repetition rate. The reported pulse energy (0.5 nJ) represents ~4 times improvement over the previously reported single-mode all-normal dispersion mode-locked lasers with multimode interference-based filtering. Numerical simulations are performed to reveal cavity and spatiotemporal mode-locking dynamics. The proposed oscillator presents an alternative approach to achieve spatiotemporal mode-locking with an all-fiber design that can be fabricated simply.
description: 6 pages, 6 figures
SHOULD AGRICULTURAL AND RESOURCE ECONOMISTS CARE THAT THE SUBJECTIVE EXPECTED UTILITY HYPOTHESIS IS FALSE?
Creators: name: Woodward, Richard T.
name: Woodward, Richard T.
Publisher: name: Unknown
Year: 1998
Subjects: Research Methods/ Statistical Methods

description: This paper argues that the subjective expected utility (SEU) hypothesis has serious limitations in both positive and normative analysis. In addition to experimental evidence, we discuss examples where alternatives to the SEU model provide a richer framework for the study problems of choice under uncertainty.
Discovery of an Unbound Hyper-Velocity Star in the Milky Way Halo
Creators: name: Brown, Warren R.
name: Geller, Margaret J.
name: Kenyon, Scott J.
name: Kurtz, Michael J.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We have discovered a star, SDSS J090745.0+024507, leaving the Galaxy with a heliocentric radial velocity of +853+-12 km/s, the largest velocity ever observed in the Milky Way halo. The star is either a hot blue horizontal branch star or a B9 main sequence star with a heliocentric distance ~55 kpc. Corrected for the solar reflex motion and to the local standard of rest, the Galactic rest-frame velocity is +709 km/s. Because its radial velocity vector points 173.8 deg from the Galactic center, we suggest that this star is the first example of a hyper-velocity star ejected from the Galactic center as predicted by Hills and later discussed by Yu & Tremaine. The star has [Fe/H]~0, consistent with a Galactic center origin, and a travel time of <80 Myr from the Galactic center, consistent with its stellar lifetime. If the star is indeed traveling from the Galactic center, it should have a proper motion of 0.3 mas/yr observable with GAIA. Identifying additional hyper-velocity stars throughout the halo will constrain the production rate history of hyper-velocity stars at the Galactic center.
description: 4 pages, submitted to ApJ Letters
Proving Highly-Concurrent Traversals Correct
Creators: name: Feldman, Yotam M. Y.
name: Khyzha, Artem
name: Enea, Constantin
name: Morrison, Adam
name: Nanevski, Aleksandar
name: Rinetzky, Noam
name: Shoham, Sharon
Publisher: name: arXiv
Year: 2020
Subjects: subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: FOS: Computer and information sciences

description: Modern highly-concurrent search data structures, such as search trees, obtain multi-core scalability and performance by having operations traverse the data structure without any synchronization. As a result, however, these algorithms are notoriously difficult to prove linearizable, which requires identifying a point in time in which the traversal's result is correct. The problem is that traversing the data structure as it undergoes modifications leads to complex behaviors, necessitating intricate reasoning about all interleavings of reads by traversals and writes mutating the data structure.
 In this paper, we present a general proof technique for proving unsynchronized traversals correct in a significantly simpler manner, compared to typical concurrent reasoning and prior proof techniques. Our framework relies only on sequential properties} of traversals and on a conceptually simple and widely-applicable condition about the ways an algorithm's writes mutate the data structure. Establishing that a target data structure satisfies our condition requires only simple concurrent reasoning, without considering interactions of writes and reads. This reasoning can be further simplified by using our framework.
 To demonstrate our technique, we apply it to prove several interesting and challenging concurrent binary search trees: the logical-ordering AVL tree, the Citrus tree, and the full contention-friendly tree. Both the logical-ordering tree and the full contention-friendly tree are beyond the reach of previous approaches targeted at simplifying linearizability proofs.
description: Extended version of a paper appearing in OOPSLA'20
Boson sampling with random numbers of photons
Creators: name: Tamma, Vincenzo
name: Laibacher, Simon
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Multiphoton interference is at the very heart of quantum foundations and applications in quantum sensing and information processing. In particular, boson sampling experiments have the potential to demonstrate quantum computational supremacy while only relying on multiphoton interference in linear optical interferometers. However, even when photonic losses are negligible, scalable experiments are challenged by the rapid decrease of the probability of success of current schemes with probabilistic sources for a large number of single photons in each experimental sample. Remarkably, we show a novel boson sampling scheme where the probability of success increases instead of decreasing with the number of input photons eventually approaching a unit value even with non deterministic sources. This is achieved by sampling at the same time in the number of occupied input ports and the number of input photons per port, differently form previous schemes where the number of occupied ports is fixed at each experimental run. Therefore, these results provide a new exciting route toward future demonstrations of quantum computational supremacy with scalable experimental resources.
description: 5 pages, 2 figures
Slinky Inflation
Creators: name: Barenboim, Gabriela
name: Lykken, Joseph
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We present a new approach to quintessential inflation, in which both dark energy and inflation are explained by the evolution of a single scalar field. We start from a simple scalar potential with both oscillatory and exponential behavior. We employ the conventional reheating mechanism of new inflation, in which the scalar decays to light fermions with a decay width that is proportional to the scalar mass. Because our scalar mass is proportional to the Hubble rate, this gives adequate reheating at early times while shutting off at late times to preserve quintessence and satisfy nucleosynthesis constraints. We discuss a simple model which solves the horizon, flatness, and "why now" problems. Without any additional tuning of parameters, this model satisfies all constraints from CMB, large scale structure, and nucleosynthesis. The predictions for the inflationary spectral indices are n_S = n_T = 1. In this model we are currently beginning the third cosmic epoch of accelerated expansion.
description: 5 pages, 2 color figures, 1 table
IMPACTS OF GLOBAL WARMING ON CROPPING PRACTICES IN ALBERTA
Creators: name: Walburger, Allan M.
name: Klein, Kurt K.
name: Walburger, Allan M.
name: Klein, Kurt K.
Publisher: name: Unknown
Year: 1998
Subjects: Environmental Economics and Policy

description: A Target MOTAD farm-level model was developed to assess the expected impacts from global warming on representative grain and oilseed farms in Alberta. It was found that a warmer climate would increase crop yields and length of the cropping season. Net returns and shadow values of land would increase substantially. Price risk generally was more important than yield risk under simulated warmer climates.
STABILIZATION OF UPLAND RICE PRODUCTION UNDER SHORTENED FALLOW IN WEST AFRICA: RESEARCH PRIORITY SETTING IN A DYNAMIC ENVIRONMENTAL AND ECONOMIC CLIMATE
Creators: name: Dalton, Timothy J.
name: Becker, Mathias
name: Johnson, David E.
name: Dalton, Timothy J.
name: Becker, Mathias
name: Johnson, David E.
Publisher: name: Unknown
Year: 1998
Subjects: Land Economics/Use
Resource /Energy Economics and Policy

description: This paper presents a dynamic model of land resource degradation and shifting rice cultivation in West Africa based upon Boserup and Dvorak. The model indicates the ex ante impact of research strategies to maximize the economic benefits of host plant resistance and land resource management and thereby stabilize yield decline and reduce land degradation.
Chirp mass based glitch identification in long duration gravitational wave transients
Creators: name: Bose, Nirban
name: Pai, Archana
name: Chandra, Koustav
name: Gayathri, V.
Publisher: name: arXiv
Year: 2020
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The data from the ground-based interferometric gravitational wave detectors(GW) is often masqueraded by highly localised short-duration glitches which pose a serious challenge for any transient GW search. In this work, we propose a glitch identification algorithm for the scenario of presence of a glitch along with a long duration GW transient. We device the chirp mass consistency parameter across different Q planes in the Q-transform. We test this algorithm over a variety of short duration glitches from the observing runs along with a long duration binary inspiral signal. The demonstration of this algorithm for a generic low mass and low eccentricity binary systems shows the direct application of it in the long duration unmodeled searches.
description: Main Paper : 7 pages and 6 figures ; Total with appendix : 8 pages and 6 figures
On 3-Coloring of $(2P_4,C_5)$-Free Graphs
Creators: name: Jelínek, Vít
name: Klimošová, Tereza
name: Masařík, Tomáš
name: Novotná, Jana
name: Pokorná, Aneta
Publisher: name: arXiv
Year: 2020
Subjects: subject: Data Structures and Algorithms (cs.DS)
subject: Discrete Mathematics (cs.DM)
subject: Combinatorics (math.CO)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics
subject: 05C15, 05C85

description: The 3-coloring of hereditary graph classes has been a deeply-researched problem in the last decade. A hereditary graph class is characterized by a (possibly infinite) list of minimal forbidden induced subgraphs $H_1,H_2,\ldots$; the graphs in the class are called $(H_1,H_2,\ldots)$-free. The complexity of 3-coloring is far from being understood, even for classes defined by a few small forbidden induced subgraphs. For $H$-free graphs, the complexity is settled for any $H$ on up to seven vertices. There are only two unsolved cases on eight vertices, namely $2P_4$ and $P_8$. For $P_8$-free graphs, some partial results are known, but to the best of our knowledge, $2P_4$-free graphs have not been explored yet. In this paper, we show that the 3-coloring problem is polynomial-time solvable on $(2P_4,C_5)$-free graphs.
description: 18 pages, 13 figures. Accepted to International Workshop on Graph-Theoretic Concepts in Computer Science (WG) 2021
C*-algebras of higher-rank graphs from groups acting on buildings, and explicit computation of their K-theory
Creators: name: Mutter, Sam A.
name: Radu, Aura-Cristiana
name: Vdovina, Alina
Publisher: name: arXiv
Year: 2020
Subjects: subject: Operator Algebras (math.OA)
subject: Group Theory (math.GR)
subject: FOS: Mathematics
subject: 46L80, 20E08

description: We unite elements of category theory, K-theory, and geometric group theory, by defining a class of groups called $k$-cube groups, which act freely and transitively on the product of $k$ trees, for arbitrary $k$. The quotient of this action on the product of trees defines a $k$-dimensional cube complex, which induces a higher-rank graph. We make deductions about the K-theory of the corresponding $k$-rank graph C*-algebras, and give explicit examples of $k$-cube groups and their K-theory. We give explicit computations of K-theory for an infinite family of $k$-rank graphs for $k\geq 3$, which is not a direct consequence of the Künneth Theorem for tensor products.
description: Published version
The meaning of cancer in a new marriage
Creators: name: Barz, Marilyn
Publisher: name: University of British Columbia
Year: 2009

description: This study explores the meaning of cancer as experienced by newly married couples. The participants were engaged as co-researchers in an attempt to understand this unique experience. In the initial interview, questions were asked to encourage storytelling and introspection. The goal of the collaboration was mutually understood to be the creation of stories that would accurately reflect each couple's experience and illuminate the meaning of that experience. Narrative accounts from the initial interviews were examined and validated by each couple in a second interview. Each narrative account was then rigorously analyzed to find themes of meaning, which were compared across accounts. Important themes emerged, giving new insights into the processes of deconstruction and reconstruction that helped the subjects to survive and make sense of the cancer experience. This study contributes to the body of research on the subjectively lived experience of cancer, and in important ways challenges some of the assumptions in the oncology literature. It is clear from the narrative accounts, for example, that the concept of recovery as an individual, sequential, and finite process does not accurately describe the recovery processes of these subjects, who experienced recovery as an ongoing, lifelong process occurring within a variety of individual and interpersonal contexts.
EXOGENOUS PRODUCTION SHOCKS AND TECHNICAL EFFICIENCY AMONG TRADITIONAL IVORIEN RICE FARMERS
Creators: name: Sherlund, Shane M.
name: Barrett, Christopher B.
name: Sherlund, Shane M.
name: Barrett, Christopher B.
Publisher: name: Unknown
Year: 1998
Subjects: subject: Crop Production/Industries
subject: Productivity Analysis
subject: Africa (Sub-Saharan)
subject: Ivory Coast
subject: production frontiers
subject: agricultural productivity
subject: rice.

description: This paper uses a unique panel data set and data envelopment analysis (DEA) to obtain estimates of technical efficiency for 492 traditional rice plots in Côte d'Ivoire. The objective of this paper is to explore the importance of explicitly controlling for exogenous shocks to production in technical efficiency estimation. We show how omission of such variables in highly stochastic production environments can lead to serious inferential errors, with potentially significant policy implications. Conventional DEA estimation of a production frontier, followed by second-stage Tobit estimation of the correlates of plot- level technical efficiency, suggest widespread and substantial inefficiency related to crop fragmentation and seed varieties. However, when one controls for unobserved groupwise cross-sectional and intertemporal heterogeneity and introduces measurable exogenous shocks into the second-stage estimation, managerial characteristics become jointly insignificant and state-conditional technical efficiency becomes nearly universal. The implication is that conventional technical efficiency estimates that refute the classic Schultzian "poor but efficient" hypothesis may be incorrect because they ignore farmers' vulnerability to adverse states of nature against which they cannot insure.
Multipole vector anomalies in the first-year WMAP data: a cut-sky analysis
Creators: name: Bielewicz, P.
name: Eriksen, H. K.
name: Banday, A. J.
name: Gorski, K. M.
name: Lilje, P. B.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We apply the recently defined multipole vector framework to the frequency-specific first-year WMAP sky maps, estimating the low-l multipole coefficients from the high-latitude sky by means of a power equalization filter. While most previous analyses of this type have considered only heavily processed (and foreground-contaminated) full-sky maps, the present approach allows for greater control of residual foregrounds, and therefore potentially also for cosmologically important conclusions. The low-l spherical harmonics coefficients and corresponding multipole vectors are tabulated for easy reference. Using this formalism, we re-assess a set of earlier claims of both cosmological and non-cosmological low-l correlations based on multipole vectors. First, we show that the apparent l=3 and 8 correlation claimed by Copi et al. (2004) is present only in the heavily processed map produced by Tegmark et al. (2003), and must therefore be considered an artifact of that map. Second, the well-known quadrupole-octopole correlation is confirmed at the 99% significance level, and shown to be robust with respect to frequency and sky cut. Previous claims are thus supported by our analysis. Finally, the low-l alignment with respect to the ecliptic claimed by Schwarz et al. (2004) is nominally confirmed in this analysis, but also shown to be very dependent on severe a-posteriori choices. Indeed, we show that given the peculiar quadrupole-octopole arrangement, finding such a strong alignment with the ecliptic is not unusual.
description: 13 pages, 2 figures; corrected typos; added reference. Accepted for publication in ApJ
title: When you can't unearth the covered up: archaeology and the memorialization of Mount Cashel orphanage
Creators: name: Osmond, Jazpyn
Publisher: name: Memorial University of Newfoundland
Year: 2020

description: Far too often, places try only to bring forth the best parts of their heritage. St. John’s, Newfoundland is no different. The site of Mount Cashel Orphanage constitutes a ‘place of shame,’ associated with a number of instances of sexual and physical abuse committed by members of the Congregation of Christian Brothers against the boys at the orphanage. Local police, the Royal Newfoundland Constabulary (RNC), and the Church covered up these allegations. In 1989, the RNC reopened an investigation, uncovering this abuse, which ultimately led to the orphanage's closure that had operated from 1898 to 1990. In 1992 Mount Cashel Orphanage was demolished, and today there is a grocery store, housing, and a memorial park, covering the site. I would argue that multiple factors explain the continuance of the cover-ups around the orphanage’s history, which does not show as a part of the area’s difficult heritage. To help combat this and to highlight how all heritage is important to the city’s narrative, I propose two ways of memorializing Mount Cashel Orphanage in this master’s thesis. This project's research involved interviewing two individuals connected to the Mount Cashel Orphanage and uses their responses regarding memorialization in conjunction with outside research.
UNDERSTANDING PRODUCTION CONTRACTS: TESTING AN AGENCY THEORY MODEL
Creators: name: Goodhue, Rachael E.
name: Rausser, Gordon C.
name: Simon, Leo K.
name: Goodhue, Rachael E.
name: Rausser, Gordon C.
name: Simon, Leo K.
Publisher: name: Unknown
Year: 1998
Subjects: Industrial Organization
Livestock Production/Industries

description: Production contracts are increasingly important in American agriculture. Unfortunately, little is known about the fundamental forces governing their adoption and design. In order to better-understand the underlying incentives, we construct and test an agency-theoretic model of broiler production contracts. We discuss the analysis' implications for industry participants and government policy.
Idéaux fermés de certaines algèbres de Beurling et application aux opérateurs à spectre dénombrable
Creators: name: Agrafeuil, Cyril
Publisher: name: arXiv
Year: 2006
Subjects: subject: Functional Analysis (math.FA)
subject: FOS: Mathematics
subject: 46J20; 47A30; 30H05

description: We denote by $\bbt$ the unit circle and by $\bbd$ the unit disc of $\bbc$. Let $s$ be a non-negative real and $ω$ a weight such that $ω(n) = (1+n)^{s} \quad (n \geq 0)$ and such that the sequence $\dsp \Big(\frac{ω(-n)}{(1+n)^{s}} \Big)_{n \geq 0}$ is non-decreasing. We define the Banach algebra $$ A_ω(\bbt) = \Big\{f \in \calc(\bbt) : \big\| f \big\|_ω = \sum_{n = -\infty}^{+\infty} | \hat{f}(n) | ω(n) < +\infty \Big\}, $$ If $I$ is a closed ideal of $A_ω(\bbt)$, we set $h^{0}(I) = \Big\{z \in \bbt : f(z) = 0 \quad (f \in I) \Big\}$. We describe here all closed ideals $I$ of $A_ω(\bbt)$ such that $h^{0}(I)$ is at most countable. A similar result is obtained for closed ideals of the algebra $A_{s}^{+}(\bbt) = \Big\{f \in A_ω(\bbt) : \hat{f}(n) = 0 \quad (n<0) \Big\}$ without inner factor. Then, we use this description to establish a link between operators with countable spectrum and interpolating sets for $\textrm{\LARGE $a$}^{\infty}$, the space of infinitely differentiable functions in the closed unit disc $\bar{\bbd}$ and holomorphic in $\bbd$.
description: 19 pages
Goal-oriented adaptive finite element methods with optimal computational complexity
Creators: name: Becker, Roland
name: Gantner, Gregor
name: Innerberger, Michael
name: Praetorius, Dirk
Publisher: name: arXiv
Year: 2021
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics

description: We consider a linear symmetric and elliptic PDE and a linear goal functional. We design and analyze a goal-oriented adaptive finite element method, which steers the adaptive mesh-refinement as well as the approximate solution of the arising linear systems by means of a contractive iterative solver like the optimally preconditioned conjugate gradient method or geometric multigrid. We prove linear convergence of the proposed adaptive algorithm with optimal algebraic rates. Unlike prior work, we do not only consider rates with respect to the number of degrees of freedom but even prove optimal complexity, i.e., optimal convergence rates with respect to the total computational cost.
The Phase Transition of Discrepancy in Random Hypergraphs
Creators: name: MacRury, Calum
name: Masařík, Tomáš
name: Pai, Leilani
name: Pérez-Giménez, Xavier
Publisher: name: arXiv
Year: 2021
Subjects: subject: Combinatorics (math.CO)
subject: Discrete Mathematics (cs.DM)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences

description: Motivated by the Beck-Fiala conjecture, we study the discrepancy problem in two related models of random hypergraphs on $n$ vertices and $m$ edges. In the first (edge-independent) model, a random hypergraph $H_1$ is constructed by fixing a parameter $p$ and allowing each of the $n$ vertices to join each of the $m$ edges independently with probability $p$. In the parameter range in which $pn \rightarrow \infty$ and $pm \rightarrow \infty$, we show that with high probability (w.h.p.) $H_1$ has discrepancy at least $Ω(2^{-n/m} \sqrt{pn})$ when $m = O(n)$, and at least $Ω(\sqrt{pn \logγ})$ when $m \gg n$, where $γ= \min\{ m/n, pn\}$. In the second (edge-dependent) model, $d$ is fixed and each vertex of $H_2$ independently joins exactly $d$ edges uniformly at random. We obtain analogous results for this model by generalizing the techniques used for the edge-independent model with $p=d/m$. Namely, for $d \rightarrow \infty$ and $dn/m \rightarrow \infty$, we prove that w.h.p. $H_{2}$ has discrepancy at least $Ω(2^{-n/m} \sqrt{dn/m})$ when $m = O(n)$, and at least $Ω(\sqrt{(dn/m) \logγ})$ when $m \gg n$, where $γ=\min\{m/n, dn/m\}$. Furthermore, we obtain nearly matching asymptotic upper bounds on the discrepancy in both models (when $p=d/m$), in the dense regime of $m \gg n$. Specifically, we apply the partial colouring lemma of Lovett and Meka to show that w.h.p. $H_{1}$ and $H_{2}$ each have discrepancy $O( \sqrt{dn/m} \log(m/n))$, provided $d \rightarrow \infty$, $d n/m \rightarrow \infty$ and $m \gg n$. This result is algorithmic, and together with the work of Bansal and Meka characterizes how the discrepancy of each random hypergraph model transitions from $Θ(\sqrt{d})$ to $o(\sqrt{d})$ as $m$ varies from $m=Θ(n)$ to $m \gg n$.
Random 2-cell embeddings of multistars
Creators: name: Loth, Jesse Campion
name: Halasz, Kevin
name: Masařík, Tomáš
name: Mohar, Bojan
name: Šámal, Robert
Publisher: name: arXiv
Year: 2021
Subjects: subject: Combinatorics (math.CO)
subject: Discrete Mathematics (cs.DM)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences
subject: 05C10

description: Random 2-cell embeddings of a given graph $G$ are obtained by choosing a random local rotation around every vertex. We analyze the expected number of faces, $\mathbb{E}[F_G]$, of such an embedding which is equivalent to studying its average genus. So far, tight results are known for two families called monopoles and dipoles. We extend the dipole result to a more general family called multistars, i.e., loopless multigraphs in which there is a vertex incident with all the edges. In particular, we show that the expected number of faces of every multistar with $n$ nonleaf edges lies in an interval of length $2/(n + 1)$ centered at the expected number of faces of an $n$-edge dipole. This allows us to derive bounds on $\mathbb{E}[F_G]$ for any given graph $G$ in terms of vertex degrees. We conjecture that $\mathbb{E}[F_G ] \le O(n)$ for any simple $n$-vertex graph $G$.
description: 15 pages, 2 figures. Accepted to European conference on combinatorics, graph theory and applications (EUROCOMB) 2021
SDSS J210014.12+004446.0: A New Dwarf Nova with Quiescent Superhumps?
Creators: name: Tramposch, Jonica
name: Homer, Lee
name: Szkody, Paula
name: Henden, Arne
name: Silvestri, Nicole M.
name: Yirak, Kris
name: Fraser, Oliver J.
name: Brinkmann, J.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report follow-up observations of the Sloan Digital Sky Survey Cataclysmic Variable SDSS J210014.12+004446.0 (hereafter SDSS J2100). We obtained photometry and spectroscopy in both outburst and quiescent states, providing the first quiescent spectrum of this source. In both states, non-sinusoidal photometric modulations are apparent, suggestive of superhumps, placing SDSS J2100 in the SU UMa subclass of dwarf novae. However, the periods during outburst and quiescence differ significantly, being 2.099 plus or minus 0.002 hr and 1.96 plus or minus 0.02 hr respectively. Our phase-resolved spectroscopy during outburst yielded an estimate of about 2 hr for the orbital period, consistent with the photometry. The presence of the shorter period modulation at quiescence is unusual, but not unique. Another atypical feature is the relative weakness of the Balmer emission lines in quiescence. Overall, we find a close similarity between SDSS J2100 and the well-studied superhump cataclysmic Variable V503 Cygni. By analogy, we suggest that the quiescent modulation is due to a tilted accretion disk -- producing negative superhumps -- and the modulation in outburst is due to positive superhumps from the precession of an elliptical disk.
description: 6 pages, 5 eps figures, accepted by PASP Dec. 16th, 2004
$^{52}$Cr Spinor Condensate$ -- $ A Biaxial or Uniaxial Spin Nematic
Creators: name: Diener, Roberto B.
name: Ho, Tin-Lun
Publisher: name: arXiv
Year: 2005
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We show that the newly discovered $^{52}$Cr Bose condensate in zero magnetic field can be a spin nematic of the following kind: A "maximum" polar state, a "co-linear" polar state, or a biaxial nematic ferromagnetic state. We also present the phase diagram with a magnetic field in the interaction subspace containing the Chromium condensate. It contains many uniaxial and biaxial spin nematic phases, which often but not always break time reversal symmetry, and can exist with or without spontaneous magnetization.
description: 4 pages, 5 figures
FEASIBILITY OF INCOME INSURANCE IN EUROPEAN AGRICULTURE
Creators: name: Meuwissen, Miranda P.M.
name: Huirne, Ruud B.M.
name: Meuwissen, Miranda P.M.
name: Huirne, Ruud B.M.
Publisher: name: Unknown
Year: 1998
Subjects: subject: Risk and Uncertainty
subject: Income variability
subject: income insurance
subject: crop and livestock farming

description: Liberalization of agricultural markets leads to new risks for European farmers. This paper studies the feasibility of income insurance schemes for European crop and livestock farmers. Different insurance topics, such as governmental reinsurance and the use of mutual insurance funds, are described and analyzed, using individual farm level data of different areas and commodities. In this paper it is argued that 'income' insurance in European agriculture should be restricted to yield-only insurance schemes that are organized per commodity and per region and in which governments play the role of 'lender of last resort.
Models of Electrodes and Contacts in Molecular Electronics
Creators: name: Ke, San-Huang
name: Baranger, Harold U.
name: Yang, Weitao
Publisher: name: arXiv
Year: 2005
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Bridging the difference in atomic structure between experiments and theoretical calculations and exploring quantum confinement effects in thin electrodes (leads) are both important issues in molecular electronics. To address these issues, we report here, by using Au-benzenedithiol-Au as a model system, systematic investigations of different models for the leads and the lead-molecule contacts: leads with different cross-sections, leads consisting of infinite surfaces, and surface leads with a local nanowire or atomic chain of different lengths. The method adopted is a non-equilibrium Green function approach combined with density functional theory calculations for the electronic structure and transport, in which the leads and molecule are treated on the same footing. It is shown that leads with a small cross-section will lead to large oscillations in the transmission function, T(E), which depend significantly on the lead structure (orientation) because of quantum waveguide effects. This oscillation slowly decays as the lead width increases, with the average approaching the limit given by infinite surface leads. Local nanowire structures around the contacts induce moderate fluctuations in T(E), while a Au atomic chain (including a single Au apex atom) at each contact leads to a significant conductance resonance.
description: 8 pages, published version, some revised figures and more in-depth discussion
Design and implementation of a tunable composite photonic crystal cavity on an optical nanofiber
Creators: name: Yalla, Ramachandrarao
name: Hakuta, Kohzo
Publisher: name: arXiv
Year: 2020
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We report a novel approach to the design and implementation of a tunable cavity on an optical nanofiber (ONF). The key point is to create a composite photonic crystal cavity (CPCC), by combining an ONF and a chirped period defect mode grating. Using numerical simulations we design the CPCC with low scattering loss while tuning the cavity resonance wavelength of \pm10 nm around the designed wavelength. We experimentally demonstrate the tunability of the CPCC, showing good agreement with the simulation results. Our results lay the foundation for a versatile platform for ONF cavity-quantum-electrodynamics with narrow bandwidth quantum emitters.
description: 7 Pages, 4 Figures
A multimode quasi-normal spectrum from a perturbed black hole
Creators: name: Capano, Collin D.
name: Cabero, Miriam
name: Westerweck, Julian
name: Abedi, Jahed
name: Kastha, Shilpa
name: Nitz, Alexander H.
name: Wang, Yi-Fan
name: Nielsen, Alex B.
name: Krishnan, Badri
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: When two black holes merge, the late stage of gravitational wave emission is a superposition of exponentially damped sinusoids. According to the black hole no-hair theorem, this ringdown spectrum depends only on the mass and angular momentum of the final black hole. An observation of more than one ringdown mode can test this fundamental prediction of general relativity. Here we provide strong observational evidence for a multimode black hole ringdown spectrum using the gravitational wave event GW190521, with a maximum Bayes factor of $56\pm1$ ($1σ$ uncertainty) preferring two fundamental modes over one. The dominant mode is the $\ell=m=2$ harmonic, and the sub-dominant mode corresponds to the $\ell=m=3$ harmonic. The amplitude of this mode relative to the dominant harmonic is estimated to be $A_{330}/A_{220} = 0.2^{+0.2}_{-0.1}$. We estimate the redshifted mass and dimensionless spin of the final black hole as $330_{-40}^{+30}~\mathrm{M}_{\odot}$ and $0.86_{-0.11}^{+0.06}$, respectively. We find that the final black hole is consistent with the no hair theorem and constrain the fractional deviation from general relativity of the sub-dominant mode's frequency to be $-0.01^{+0.08}_{-0.09}$.
description: Accepted for publication in PRL. 7 pages, 4 figures, plus supplemental. Data available at https://github.com/gwastro/BH-Spectroscopy-GW190521
Noncommutativity vs. Transversality in QED in a strong magnetic field
Creators: name: Hashimoto, Michio
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Quantum electrodynamics (QED) in a strong constant magnetic field is investigated from the viewpoint of its connection with noncommutative QED. It turns out that within the lowest Landau level (LLL) approximation the 1-loop contribution of fermions provides an effective action with the noncommutative U(1)_{NC} gauge symmetry. As a result, the Ward-Takahashi identities connected with the initial U(1) gauge symmetry are broken down in the LLL approximation. On the other hand, it is shown that the sum over the infinite number of the higher Landau levels (HLL's) is relevant despite the fact that each contribution of the HLL is suppressed. Owing to this nondecoupling phenomenon the transversality is restored in the whole effective action. The kinematic region where the LLL contribution is dominant is also discussed.
description: 11 pages, 2 figures; references added; based on talk given at The 27th Annual Montreal-Rochester-Syracuse-Toronto Conference on High Energy Physics (MRST 2005), Utica, New York, 16-18 May 2005
The interaction of Type Iax supernova ejecta with a helium companion star
Creators: name: Zeng, Yaotian
name: Liu, Zheng-Wei
name: Han, Zhanwen
Publisher: name: arXiv
Year: 2020
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Type Iax supenovae (SNe Iax) are an important sub-luminous class of SNe Ia. However, their progenitors and explosion mechanism have not been understood yet. It has been suggested that SNe Iax may be produced from weak deflagration explosions of Chandrasekhar-mass white dwarfs (WDs) in binary systems with a helium (He) star donor. In such progenitor systems, the stripped He companion material caused by the ejecta-companion interaction is expected to present some He features in their late-time spectra. However, the detection of He lines in late-time spectra of SNe Iax has not yet been successful, which gives an upper limit on the amount of stripped He mass of < 0.002-0.1 solar masses. In this work, we study the interaction between SN Iax ejecta and a He star companion by performing three-dimensional hydrodynamical simulations with a weak pure deflagration explosion model. We find that about 0.004 solar masses of He material can be stripped off from the companion star by SN explosion, which is very close to (or lower than) the observational upper-limit on the total stripped He mass in SNe Iax. We, therefore, conclude that non-detection of He lines in late-time spectra of SNe Iax could be reasonably explained if they are indeed resulted from weak pure deflagration explosions of Chandrasekhar-mass WDs in progenitor systems with a He star donor.
description: 10 pages, 5 figures, accepted for publication in Astrophysical Journal (ApJ)
Ergodicity of the Fisher infinitesimal model with quadratic selection
Creators: name: Calvez, Vincent
name: Lepoutre, Thomas
name: Poyato, David
Publisher: name: arXiv
Year: 2021
Subjects: subject: Probability (math.PR)
subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35B40, 35P30, 35Q92, 47G20, 92D15

description: We study the convergence towards a unique equilibrium distribution of the solutions to a time-discrete model with non-overlapping generations arising in quantitative genetics. The model describes the dynamics of a phenotypic distribution with respect to a multi-dimensional trait, which is shaped by selection and Fisher's infinitesimal model of sexual reproduction. We extend some previous works devoted to the time-continuous analogues, that followed a perturbative approach in the regime of weak selection, by exploiting the contractivity of the infinitesimal model operator in the Wasserstein metric. Here, we tackle the case of quadratic selection by a global approach. We establish uniqueness of the equilibrium distribution and exponential convergence of the renormalized profile. Our technique relies on an accurate control of the propagation of information across the large binary trees of ancestors (the pedigree chart), and reveals an ergodicity property, meaning that the shape of the initial datum is quickly forgotten across generations. We combine this information with appropriate estimates for the emergence of Gaussian tails and propagation of quadratic and exponential moments to derive quantitative convergence rates. Our result can be interpreted as a generalization of the Krein-Rutman theorem in a genuinely non-linear, and non-monotone setting.
description: 49 pages, 11 figures
Die Anzahl der Angaben zur Konstruktion eines n-Ecks
Creators: name: Schröer, Harald
Publisher: name: Zenodo
Year: 2021
Subjects: Anzahl, Konstruktion,n-Eck, Sehnenviereck, Tangentenviereck, Sehnen-n-Eck,Tangenten-n-Eck

description: Berechnung der Anzahl von Angaben zwecks Konstruktion eines n-Eck, insbesondere auch Sehnen-n-Eck und Tangenten-n-Eck
THE LONG-RUN EFFICIENCY OF BLOCK-RATE PRICING
Creators: name: Ziv, Bar-Shira
name: Finkelshtain, Israel
name: Ziv, Bar-Shira
name: Finkelshtain, Israel
Publisher: name: Unknown
Year: 1998
Subjects: Demand and Price Analysis
Industrial Organization
Institutional and Behavioral Economics

description: It is widely believed that block-rate pricing separates income redistribution from efficiency consideration. We show that social optimum can not be implementable by block-rate pricing. Particularly, block-rate pricing with marginal cost as the highest block induces over production and utilization of resources, too-small firm size, and welfare losses.
Zilch Vortical Effect, Berry Phase, and Kinetic Theory
Creators: name: Huang, Xu-Guang
name: Mitkin, Pavel
name: Sadofyev, Andrey V.
name: Speranza, Enrico
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: Rotating photon gas exhibits a chirality separation along the angular velocity which is manifested through a generation of helicity and zilch currents. In this paper we study this system using the corresponding Wigner function and construct elements of the covariant chiral kinetic theory for photons from first principles. The Wigner function is solved order-by-order in $\hbar$ and the unconstrained terms are fixed by matching with quantum field theory results. We further consider the zilch and helicity currents and show that both manifestations of the chirality transport originate in the Berry phase of photons similarly to other chiral effects. Constructing the kinetic description from the Wigner function we find that the frame vector needed to fix the definition of spin of a massless particle is, in fact, the vector of the residual gauge freedom for the free Maxwell theory. We also briefly comment on the possible relation between vortical responses in rotating systems of massless particles and the anomalies of underlying quantum field theory.
description: 19 pages, no figures
Towards quantum Mechanics on the curved cotangent bundle
Creators: name: Wagner, Fabian
Publisher: name: arXiv
Year: 2021
Subjects: 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: The minimal-length paradigm is a cornerstone of quantum gravity phenomenology. Recently, it has been demonstrated that minimal-length quantum mechanics can alternatively be described as an undeformed theory set on a nontrivial momentum space. However, there is no fully consistent formulation of these theories beyond Cartesian coordinates in flat space and, in particular, no position representation. This paper is intended to take the first steps in bridging this gap. We find a natural position representation of the position and momentum operators on general curved cotangent bundles. In an expansion akin to Riemann normal coordinates with curvature in both position and momentum space, we apply the formalism perturbatively to the isotropic harmonic oscillator and the hydrogenic atom. Due to the symmetry of the harmonic oscillator under exchange of positions and momenta, we show that it is impossible to distinguish position- from momentum- space curvature with oscillators alone. Thus, we obtain an instantiation of Born reciprocity on the curved cotangent bundle, i. e. in precisely the way Born originally envisioned. It manifests itself as a symmetry mixing UV and IR physics, reminiscent of T-duality in string theory.
description: 18 pages. v3: version accepted for publication in CQG, some paragraphs added, minor modifications to v2; v2: major changes - much more streamlined and rigorous derivation and new results in comparison to v1
On Solving the Coronal Heating Problem
Creators: name: Klimchuk, James A.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: This article assesses the current state of understanding of coronal heating, outlines the key elements of a comprehensive strategy for solving the problem, and warns of obstacles that must be overcome along the way.
description: Accepted by Solar Physics; Published by Solar Physics
The square-lattice F model revisited: a loop-cluster update scaling study
Creators: name: Weigel, Martin
name: Janke, Wolfhard
Publisher: name: arXiv
Year: 2005
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: The six-vertex F model on the square lattice constitutes the unique example of an exactly solved model exhibiting an infinite-order phase transition of the Kosterlitz-Thouless type. As one of the few non-trivial exactly solved models, it provides a welcome gauge for new numerical simulation methods and scaling techniques. In view of the notorious problems of clearly resolving the Kosterlitz-Thouless scenario in the two-dimensional XY model numerically, the F model in particular constitutes an instructive reference case for the simulational description of this type of phase transition. We present a loop-cluster update Monte Carlo study of the square-lattice F model, with a focus on the properties not exactly known such as the polarizability or the scaling dimensions in the critical phase. For the analysis of the simulation data, finite-size scaling is explicitly derived from the exact solution and plausible assumptions. Guided by the available exact results, the careful inclusion of correction terms in the scaling formulae allows for a reliable determination of the asymptotic behaviour.
description: 28 pages, 11 figures, 4 tables, revised version as published
ENVIRONMENTAL RISK AND AGRI-ENVIRONMENTAL POLICY DESIGN
Creators: name: Horan, Richard D.
name: Claassen, Roger
name: Cooper, Joseph C.
name: Horan, Richard D.
name: Claassen, Roger
name: Cooper, Joseph C.
Publisher: name: Unknown
Year: 2000
Subjects: Agricultural and Food Policy
Environmental Economics and Policy

description: Agricultural nonpoint pollution is inherently stochastic (e.g., due to weather). In theory, this randomness has implications for the choice and design of policy instruments. However, very few empirical studies have modeled natural variability. This paper investigates the importance of stochastic processes for the choice and design of alternative nonpoint instruments. The findings suggest that not explicitly considering the stochastic processes in the analysis can produce significantly biased results.