cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Factors affecting post-logging debris flow initiation in steep forested gullies of the Southwestern Canadian cordillera, Fraser Valley Region
Creators: name: Brayshaw, Drew Devoe
Publisher: name: University of British Columbia
Year: 2009

description: This thesis examines the factors which influence debris flow initiation in gullies. The analysis covers 53 gullies located in two neighboring, but separate, regions: the Chilliwack Valley region of the Cascade Mountains, and the Norrish Creek area of the southern Coast Mountains, respectively located to the south and north of the Fraser Valley in southwestern British Columbia. Lithology varies greatly between the two regions, but climate and logging histories are similar. All gullies studied had been logged during the period 1981 to 1990. Gullies were selected on the basis of their having experienced slope failures which potentially could have caused debris flows to occur. A wide range of geotechnical and morphometric terrain variables was measured in each gully system, at three different spatial scales: that of the entire gully system, that of the individual gully reach, and that of the individual slope failure. Gullies were also evaluated by the method of assessing Debris Flow Initiation Potential (DFLP) used in the Gully Assessment Procedures (GAP) section of the B.C. Forest Practices Code. Analysis of data showed that the most important variables influencing debris flow initiation in gullies were surficial material, gully wall gradient and length, and channel gradient, although not exactly in the manner which the DFLP assessment had predicted. Volume of the initial failure, amount of sediment stored in the gully channel, and angle of entry of the failure into the channel were other parameters which proved to be important. Regional variation in lithology seemed mainly to affect gully morphology, and not to influence debris flow initiation directly. Revisions were suggested for the DFLP assessment based on the observed behaviour of the most important and most easily and accurately measured variables. The current method uses the parameters of gully wall slope angle and surficial material type to qualitatively estimate the chance that a wall failure will occur, and the parameters of gully wall length and channel gradient to qualitatively estimate the chance that a slope failure entering the channel will initiate a debris flow. The two estimates are then combined into an overall estimate of the qualitative probability of debris flow initiation, using a three-class system of high, medium and low hazard. The revised method of DFLP evaluation devised in this thesis is similarity qualitative. The revised estimate of the chance of slope failure is determined using gully wall length in addition to wall slope gradient and surficial material type, and the chance of debris flow initiation from failure is determined using channel gradient only. The resulting estimate of debris flow initiation potential uses only two qualitative hazard classes, high and low.
On the distribution of initial masses of stellar clusters inferred from synthesis models
Creators: name: Cervino, M.
name: Valls-Gabaud, D.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The fundamental properties of stellar clusters, such as the age or the total initial mass in stars, are often inferred from population synthesis models. The predicted properties are then used to constrain the physical mechanisms involved in the formation of such clusters in a variety of environments. Population synthesis models cannot, however, be applied blindy to such systems. We show that synthesis models cannot be used in the usual straightforward way to small-mass clusters (say, M < few times 10**4 Mo). The reason is that the basic hypothesis underlying population synthesis (a fixed proportionality between the number of stars in the different evolutionary phases) is not fulfilled in these clusters due to their small number of stars. This incomplete sampling of the stellar mass function results in a non-gaussian distribution of the mass-luminosity ratio for clusters that share the same evolutionary conditions (age, metallicity and initial stellar mass distribution function). We review some tests that can be carried out a priori to check whether a given cluster can be analysed with the fully-sampled standard population synthesis models, or, on the contrary, a probabilistic framework must be used. This leads to a re-assessment in the estimation of the low-mass tail in the distribution function of initial masses of stellar clusters.
description: 5 pages, 1 figure, to appear in ``Young Massive Star Clusters - Initial Conditions and Environments'', 2008, Astrophysics & Space Science, eds. E. Perez, R. de Grijs, R. M. Gonzalez Delgado
Testing the intrinsic scatter of the asteroseismic scaling relations with Kepler red giants
Creators: name: Li, Yaguang
name: Bedding, Timothy R.
name: Stello, Dennis
name: Sharma, Sanjib
name: Huber, Daniel
name: Murphy, Simon J.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Asteroseismic scaling relations are often used to derive stellar masses and radii, particulaly for stellar, exoplanet, and Galactic studies. It is therefore important that their precisions are known. Here we measure the intrinsic scatter of the underlying seismic scaling relations for $Δν$ and $ν_{\rm max}$, using two sharp features that are formed in the H--R diagram (or related diagrams) by the red giant populations. These features are the edge near the zero-age core-helium-burning phase, and the strong clustering of stars at the so-called red giant branch bump. The broadening of those features is determined by factors including the intrinsic scatter of the scaling relations themselves, and therefore it is capable of imposing constraints on them. We modelled Kepler stars with a Galaxia synthetic population, upon which we applied the intrinsic scatter of the scaling relations to match the degree of sharpness seen in the observation. We found that the random errors from measuring $Δν$ and $ν_{\rm max}$ provide the dominating scatter that blurs the features. As a consequence, we conclude that the scaling relations have intrinsic scatter of $\sim0.5\%$ ($Δν$), $\sim1.1\%$ ($ν_{\rm max}$), $\sim1.7\%$ ($M$) and $\sim0.4\%$ ($R$), for the SYD pipeline measured $Δν$ and $ν_{\rm max}$. This confirms that the scaling relations are very powerful tools. In addition, we show that standard evolution models fail to predict some of the structures in the observed population of both the HeB and RGB stars. Further stellar model improvements are needed to reproduce the exact distributions.
description: accepted for publication in MNRAS. comments welcome. 12 pages, 11 figures
On random digraphs and cores
Creators: name: Parsa, Esmaeil
name: Kayll, P. Mark
Publisher: name: arXiv
Year: 2021
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: Primary 05C80, 05C20, Secondary 05C15, 60C05

description: An acyclic homomorphism of a digraph $C$ to a digraph $D$ is a function $ρ\colon V(C)\to V(D)$ such that for every arc $uv$ of $C$, either $ρ(u)=ρ(v)$, or $ρ(u)ρ(v)$ is an arc of $D$ and for every vertex $v\in V(D)$, the subdigraph of $C$ induced by $ρ^{-1}(v)$ is acyclic. A digraph $D$ is a core if the only acyclic homomorphisms of $D$ to itself are automorphisms. In this paper, we prove that for certain choices of $p(n)$, random digraphs $D\in D(n,p(n))$ are asymptotically almost surely cores. For digraphs, this mirrors a result from [A. Bonato and P. Prałat, The good, the bad, and the great: homomorphisms and cores of random graphs, Discrete Math., 309 (2009), no. 18, 5535-5539; MR2567955] concerning random graphs and cores.
description: 9 pages, to appear in Australasian Journal of Combinatorics
Bell-type correlation at quantum phase transitions in spin-1 chain
Creators: name: Lee, Dongkeun
name: Son, Wonmin
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: For the identification of non-trivial quantum phase, we exploit a Bell-type correlation that is applied to the one-dimensional spin-1 XXZ chain. It is found that our generalization of bipartite Bell correlation can take a decomposed form of transverse spin correlation together with high-order terms. The formulation of density-matrix renormalisation group is utilized to obtain the ground state of a given Hamiltonian with non-trivial phase. Subsequently Bell-SLK-type generalized correlation is evaluated through the analysis of the matrix product state. Diverse classes of quantum phase transitions in the spin-1 model are identified precisely through the evaluation of the first and the second moments of the generalized Bell correlations. The role of high-order terms in the criticality has been identified and their physical implications for the quantum phase has been revealed.
description: 10 pages, 12 figures
ТРАНСМИЛЛИЙ УЮШГАН ЖИНОЯТЧИЛИК ТУШУНЧАСИ ВА УНГА ҚАРШИ КУРАШНИНГ ЎЗИГА ХОС ХУСУСИЯТЛАРИ
Creators: name: Рахимов, Нариман
Publisher: name: Zenodo
Year: 2024

description: Мақолада траснмиллий уюшган жиноятчилик тушунчаси, ўзига хос хусусиятлари, олимларнинг фикрлари ва трансмиллий уюшган жиноятчиликка қарши курашнинг айрим масалалари кўрсатиб ўтилган.
Didinium nasutum Stein 1859
Creators: name: Durán-Ramírez, Carlos Alberto
name: Dias, Roberto Júnio Pedroso
name: Estrada, Rosaura Mayén-
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Chromista
Ciliophora
Gymnostomatea
Haptorida
Didiniidae
Didinium
Didinium nasutum

description: Didinium nasutum (Müller, 1773) Stein, 1859
Distribution. COLOMBIA: Lloró (Paz 1980), (Gs).
description: Published as part of Durán-Ramírez, Carlos Alberto, Dias, Roberto Júnio Pedroso & Estrada, Rosaura Mayén-, 2020, Checklist of ciliates (Alveolata: Ciliophora) that inhabit in bromeliads from the Neotropical Region, pp. 1-36 in Zootaxa 4895 (1) on page 15, DOI: 10.11646/zootaxa.4895.1.1, http://zenodo.org/record/4321437
Charmonium spectral functions in N_f=2 QCD at high temperature
Creators: name: Aarts, G.
name: Allton, C. R.
name: Morrin, R.
name: Cais, A. P. O
name: Oktay, M. B.
name: Peardon, M. J.
name: Skullerud, J. I.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: Charmonium systems in two-flavour QCD at non-zero temperature are studied at, and above the deconfining transition. Using anisotropic lattices the MEM approach is used to extract spectral functions for these channels. By carefully varying some of the irrelevant parameters in the MEM procedure, we confirm that our systematic effects are under control. The eta_c and J/psi states are found to persist at temperatures >~ 1.3 T_c in agreement with our previous dynamical studies.
description: 7 pages, talk presented at Lattice06 (High Temperature and Density), Tuscon, Arizon, July 2006
Oxidised cosmic acceleration
Creators: name: Wesley, Daniel H.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Astrophysics (astro-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We give detailed proofs of several new no-go theorems for constructing flat four-dimensional accelerating universes from warped dimensional reduction. These new theorems improve upon previous ones by weakening the energy conditions, by including time-dependent compactifications, and by treating accelerated expansion that is not precisely de Sitter. We show that de Sitter expansion violates the higher-dimensional null energy condition (NEC) if the compactification manifold M is one-dimensional, if its intrinsic Ricci scalar R vanishes everywhere, or if R and the warp function satisfy a simple limit condition. If expansion is not de Sitter, we establish threshold equation-of-state parameters w below which accelerated expansion must be transient. Below the threshold w there are bounds on the number of e-foldings of expansion. If M is one-dimensional or R everywhere vanishing, exceeding the bound implies the NEC is violated. If R does not vanish everywhere on M, exceeding the bound implies the strong energy condition (SEC) is violated. Observationally, the w thresholds indicate that experiments with finite resolution in w can cleanly discriminate between different models which satisfy or violate the relevant energy conditions.
description: v2: corrections, references added
On the ergodicity properties of some adaptive MCMC algorithms
Creators: name: Andrieu, Christophe
name: Moulines, Éric
Publisher: name: arXiv
Year: 2006
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 65C05, 65C40, 60J27, 60J35 (Primary) 93E35 (Secondary)

description: In this paper we study the ergodicity properties of some adaptive Markov chain Monte Carlo algorithms (MCMC) that have been recently proposed in the literature. We prove that under a set of verifiable conditions, ergodic averages calculated from the output of a so-called adaptive MCMC sampler converge to the required value and can even, under more stringent assumptions, satisfy a central limit theorem. We prove that the conditions required are satisfied for the independent Metropolis--Hastings algorithm and the random walk Metropolis algorithm with symmetric increments. Finally, we propose an application of these results to the case where the proposal distribution of the Metropolis--Hastings update is a mixture of distributions from a curved exponential family.
description: Published at http://dx.doi.org/10.1214/105051606000000286 in the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org)
A Modified TreePM Code
Creators: name: Khandai, Nishikanta
name: Bagla, J. S.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We discuss the performance characteristics of using the modification of the tree code suggested by Barnes \citep{1990JCoPh..87..161B} in the context of the TreePM code. The optimisation involves identifying groups of particles and using only one tree walk to compute force for all the particles in the group. This modification has been in use in our implementation of the TreePM code for some time, and has also been used by others in codes that make use of tree structures. In this paper, we present the first detailed study of the performance characteristics of this optimisation. We show that the modification, if tuned properly can speed up the TreePM code by a significant amount. We also combine this modification with the use of individual time steps and indicate how to combine these two schemes in an optimal fashion. We find that the combination is at least a factor of two faster than the modified TreePM without individual time steps. Overall performance is often faster by a larger factor, as the scheme of groups optimises use of cache for large simulations.
description: 16 pages, 5 figures; Accepted for publication in Research In Astronomy and Astrophysics (RAA)
Copula-Based Bounds for Multi-User Communications -- Part II: Outage Performance
Creators: name: Besser, Karl-Ludwig
name: Jorswieck, Eduard A.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: In the first part of this two-part letter, we introduced methods to study the impact of dependency on the expected value of functions of two random variables. In this second part, we present tools to derive worst- and best-case bounds on the outage probability of multi-user communication systems, including multiple access channels, wiretap channels, and reconfigurable intelligent surface-assisted channels.
description: 5 pages, 5 figures
The invariants of a genus one curve
Creators: name: Fisher, Tom
Publisher: name: arXiv
Year: 2006
Subjects: subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 11G05, 11Y40, 13A50, 14H25

description: It was first pointed out by Weil that we can use classical invariant theory to compute the Jacobian of a genus one curve. The invariants required for curves of degree n = 2,3,4 were already known to the nineteenth centuary invariant theorists. We have succeeded in extending these methods to curves of degree n = 5, where although the invariants are too large to write down as explicit polynomials, we have found a practical algorithm for evaluating them.
description: 37 pages
Particle acceleration in relativistic collisionless shocks: Fermi process at last?
Creators: name: Spitkovsky, Anatoly
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present evidence that relativistic shocks propagating in unmagnetized plasmas can self-consistently accelerate particles. We use long-term two-dimensional particle-in-cell simulations to study the well-developed shock structure in unmagnetized pair plasma. The particle spectrum downstream of such a shock consists of two components: a relativistic Maxwellian, with characteristic temperature set by the upstream kinetic energy of the flow, and a high-energy tail, extending to energies >100 times that of the thermal peak. This tail is best fitted as a power law in energy with index -2.4+-0.1, modified by an exponential cutoff. The cutoff moves to higher energies with time of the simulation, leaving a larger power law range. The number of particles in the tail is ~1% of the downstream population, and they carry ~10% of the kinetic energy in the downstream. Upon investigation of the trajectories of particles in the tail, we find that the energy gains occur as particles bounce between the upstream and downstream regions in the magnetic fields generated by the Weibel instability. We compare this mechanism to the first order Fermi acceleration, and set a lower limit on the efficiency of shock acceleration process.
description: 4 pages, 3 figures
Tetrads in Yang-Mills geometrodynamics
Creators: name: Garat, Alcides
Publisher: name: arXiv
Year: 2006
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: A new set of tetrads is introduced within the framework of SU(2) X U(1) Yang-Mills field theories in four dimensional Lorentz curved spacetimes. Each one of these tetrads diagonalizes separately and explicitly each term of the Yang-Mills stress-energy tensor. Therefore, three pairs of planes also known as blades, can be defined, and make up the underlying geometrical structure, at each point. These tetrad vectors are gauge dependent on one hand, and also in their definition, there is an additional inherent freedom in the choice of two vector fields. In order to get rid of the gauge dependence, another set of tetrads is defined, such that the only choice we have to make is for the two vector fields. A particular choice is made for these two vector fields such that they are gauge dependent, but the transformation properties of these tetrads are analogous to those already known for curved spacetimes where only electromagnetic fields are present. This analogy allows to establish group isomorphisms between the local gauge group SU(2), and the tensor product of the groups of local Lorentz tetrad transformations, either on blade one or blade two. These theorems show explicitly that the local internal groups of transformations are isomorphic to local spacetime groups of transformations. As an example of application of these new tetrads, we exhibit three new gauge invariant objects, and using these objects we show how to diagonalize the Yang-Mills stress-energy tensor in a gauge invariant way.
description: This new version has a new abstract and the introduction has been modified. There is also a new section, applications. This new section has two subsections: Gauge invariants and Diagonalization of the stress-energy tensor. The conclusion section has also been substantially modified. There is a new appendix
A Redshift for the First Einstein Ring, MG 1131+0456
Creators: name: Stern, Daniel
name: Walton, Dominic
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: MG 1131+0456 is a radio-selected gravitational lens, and is the first known Einstein ring. Discovered in 1988, the system consists of a bright radio source imaged into a ring and two compact, flat-spectrum components separated by 2.1 arcsec. The ring is optically faint (R = 23.3), rising steeply into the near- and mid-infrared (K = 17.8; W2 = 13.4). The system has been intensively studied in the intervening years, including high-resolution radio imaging, radio monitoring, and near-infrared imaging with Hubble and Keck. The lensing galaxy is at z(lens) = 0.844. However, to date, no spectroscopic redshift had been reported for the lensed source. Using archival Keck data from 1997, we report the robust detection of a single narrow emission line at 5438 Angstroms, which we associate with CIII] 1909 from a type-2 quasar at z(source) = 1.849. Support for this redshift identification comes from weaker emission associated with CIV 1549 and HeII 1640, typical of type-2 quasars, as well as the lack of emission lines in archival near-infrared Keck spectroscopy. We also present, for the first time, Cycle 1 Chandra observations of MG 1131+0456, which clearly resolves into two point sources with a combined flux of ~1e-13 erg/cm2/s and a best-fit column density of ~3e22 /cm2. We suggest a new method to identify candidate lensed active galactic nuclei from low-resolution X-ray surveys such as eROSITA by targeting sources that have anomalously high X-ray luminosity given their mid-infrared luminosity.
description: 5 pages, 3 figures; published in ApJ Letters
Chandra Observations of the Eagle Nebula. I. Embedded Young Stellar Objects near the Pillars of Creation
Creators: name: Linsky, Jeffrey L.
name: Gagne, Marc
name: Mytyk, Anna
name: McCaughrean, Mark
name: Andersen, Morten
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present and analyze the first high-resolution X-ray images ever obtained of the Eagle Nebula star-forming region. On 2001 July 30 the Chandra X-ray Observatory obtained a 78 ks image of the Eagle Nebula (M 16) that includes the core of the young galactic cluster NGC 6611 and the dark columns of dust and cold molecular gas in M 16 known as the Pillars of Creation. We find a total of 1101 X-ray sources in the 17'x17' ACIS-I field of view. Most of the X-ray sources are low mass pre-main-sequence or high-mass main-sequence stars in this young cluster. A handful of hard X-ray sources in the pillars are spatially coincident with deeply embedded young stellar objects seen in high-resolution near-infrared images recently obtained with the VLT (McCaughrean & Andersen 2002). In this paper, we focus on the 40 X-ray sources in and around Pillars 1-4 at the heart of the Eagle Nebula. None of the X-ray sources are associated with the evaporating gaseous globules (EGGs) first observed by Hester et al. (1996) in HST WFPC2 images of M 16, implying that either the EGGs do not contain protostars or that the protostars have not yet become X-ray active. Eight X-ray counts are coincident with the Herbig-Haro object HH216, implying log L_X~30.0.
description: 35 pages, 7 color figures, accepted by ApJ
An Instructional Scaffolding for Intuitive Explanation of "Why does not a spinning top collapse?"
Creators: name: Hwang, Won-Young
Publisher: name: arXiv
Year: 2006
Subjects: subject: Classical Physics (physics.class-ph)
subject: Physics Education (physics.ed-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: "Why does not a spinning top collapse?" is a puzzling question. Standard solution using angular momentum and torque is not intuitive enough. Thus intuitive explanations for the question have been proposed. We provide scaffolding for an intuitive explanation for the question. Accelerated point-masses in the top exert forces on the frame, which balances the effect due to gravity. The explanation is supplemented by the two following points. A more rigorous conceptual framework of the explanation is provided. A full calculation of trajectory is given. Nutation of spinning top is a difficult issue to understand physically. However, the nutation can also be understood by the intuitive explanation. We discuss another intuitive explanation.
description: 5 pages, 4 figures
Magnetic field evolution in relativistic unmagnetized collisionless shocks
Creators: name: Keshet, Uri
name: Katz, Boaz
name: Spitkovsky, Anatoly
name: Waxman, Eli
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: Plasma Physics (physics.plasm-ph)
subject: Space Physics (physics.space-ph)
subject: FOS: Physical sciences

description: We study relativistic unmagnetized collisionless shocks using unprecedentedly large particle-in-cell simulations of two-dimensional pair plasma. High energy particles accelerated by the shock are found to drive magnetic field evolution on a timescale >10^4 plasma times. Progressively stronger magnetic fields are generated on larger scales in a growing region around the shock. Shock-generated magnetic fields and accelerated particles carry >1% and >10% of the downstream energy flux, respectively. Our results suggest limits on the magnetization of relativistic astrophysical flows.
description: ApJ Letters, published (minor corrections, results unchanged)
Collusion attack and counterattack on the quantum key agreement via non-maximally entangled cluster states
Creators: name: Gu, Jun
name: Hwang, Tzonelih
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: Cryptography and Security (cs.CR)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Recently, Li et al. (Int J Theor Phys: DOI: 10.1007/s10773-020-04588-w, 2020) proposed a multiparty quantum key agreement protocol via non-maximally entangled cluster states. They claimed that the proposed protocol can help all the involved participants have equal influence on the final shared key. However, this study points out a loophole that makes Li et al.'s protocol suffer from a collusion attack, i.e. several dishonest participants can conspire to manipulate the final shared key without being detected by others. To avoid this loophole, an improvement is proposed here.
A Smoothed GPY Sieve
Creators: name: Motohashi, Yoichi
name: Pintz, Janos
Publisher: name: arXiv
Year: 2006
Subjects: subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: Primary 11N05, Secondary 11P32

description: We show a smoothed version of Goldston-Pintz-Yildirim's sifting argument to detect small gaps between primes, which has a higly flexible error term. Our argument is applicable to high dimensional Selberg sieve situations as well, although the relevant details are not stated explicitly. In the present v.2, we have added Appendix in which we made a minor correction to our reasoning following formula (5.14). We are indebted to Professor Terrence Tao for pointing out the necessity of this amendment. The text of the original version has not been changed, except for a correction of the title in the item [2] of the references.
description: 17 pages
Predictions for Nongaussianity from Nonlocal Inflation
Creators: name: Barnaby, Neil
name: Cline, James M.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Astrophysics (astro-ph)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In our previous work the nonlinearity parameter f_NL, which characterizes nongaussianity in the cosmic microwave background, was estimated for a class of inflationary models based on nonlocal field theory. These models include p-adic inflation and generically have the remarkable property that slow roll inflation can proceed even with an extremely steep potential. Previous calculations found that large nongaussianity is possible; however, the technical complications associated with studying perturbations in theories with infinitely many derivatives forced us to provide only an order of magnitude estimate for f_NL. We reconsider the problem of computing f_NL in nonlocal inflation models, showing that a particular choice of field basis and recent progress in cosmological perturbation theory makes an exact computation possible. We provide the first quantitatively accurate computation of the bispectrum in nonlocal inflation, confirming our previous claim that it can be observably large. We show that the shape of the bispectrum in this class of models makes it observationally distinguishable from Dirac-Born-Infeld inflation models.
description: 26 pages, 5 figures; references added, sign convention for f_NL clarified, minor corrections
Experimental observation of pinned solitons in a flowing dusty plasma
Creators: name: Arora, Garima
name: Bandyopadhyay, P
name: Hariprasad, M G
name: Sen, A
Publisher: name: arXiv
Year: 2020
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: Pinned solitons are a special class of nonlinear solutions created by a supersonically moving object in a fluid. They move with the same velocity as the moving object and thereby remain pinned to the object. A well known hydrodynamical phenomenon, they have been shown to exist in numerical simulation studies but to date have not been observed experimentally in a plasma. In this paper we report the first experimental excitation of pinned solitons in a dusty (complex) plasma flowing over a charged obstacle. The experiments are performed in a Π shaped Dusty Plasma Experimental (DPEx) device in which a dusty plasma is created in the background of a DC glow discharge Ar plasma using micron sized kaolin dust particles. A biased copper wire creates a potential structure that acts as a stationary charged object over which the dust fluid is made to flow at a highly supersonic speed. Under appropriate conditions nonlinear stationary structures are observed in the laboratory frame that correspond to pinned structures moving with the speed of the obstacle in the frame of the moving fluid. A systematic study is made of the propagation characteristics of these solitons by carefully tuning the flow velocity of the dust fluid by changing the height of the potential structure. It is found that the nature of the pinned solitons changes from a single humped one to a multi-humped one and their amplitudes increase with an increase of the flow velocity of the dust fluid. The experimental findings are then qualitatively compared with the numerical solutions of a model forced Korteweg de Vries (fKdV) equation.
description: The manuscript contains nine pages and ten figures
Wh-constructions in NÃªhiyawÃªwin (Plains Cree)
Creators: name: Blain, Eleanor M.
Publisher: name: University of British Columbia
Year: 2009

description: This thesis provides an analysis of wh-questions in Nêhiyawêwin (Plains Cree). The study is done within the Principles and Parameters framework (Chomsky 1981, 1986, 1995). I argue that Nêhiyawêwin wh-words like awfna 'who' are not generated in argument position and do not undergo A-bar movement to Spec CP (Chapter 3). Rather, they are licensed as the predicate of a nominal clause, and respect the same syntactic constraints as other nominal clauses: they are strictly predicatê-initial; obey a referentiality hierarchy; and display agreement for number, animacy and obviation (chapter 4). I analyze Nêhiyawêwin nominal clauses as IP with a null Infl head in which the predicate fronts to Spec CP. The clausê-initial position of the wh-word is thus part of a more general process of predicatefronting. The nominal clause analysis of wh-words accounts for the absence of wh-movement per se in the language, as well as for the absence of wh in situ. However, based on their interpretive properties, wh-questions must contain an operator-variable chain. I argue that the operator-variable relation arises when the subject of the nominal clause links to an A-position in a subordinate clause. This occurs in one of two ways: by means of the kâ-complementizer or the ê-complementizer (Chapter 5). If the subordinate clause has kâ-, the resulting structure is a relative clause which restricts the reference of the subject. This yields a cleft construction: Who is it[sub i] that Mary likes t[sub i] ? If the subordinate clause has ê-, the clauses are conjoined, and null-operator movement in the subordinate clause forces an anaphoric relation between the wh-word and the A-position in the ê- clause: Who is he[sub i] & OP[sub i] Mary likes him[sub i]. Having shown how Nêhiyawêwin wh-words are associated with an operator-variable chain, I then consider the consequences of the proposed analysis (Chapter 6). A defining property of wh-chains is their sensitivity to island effects. Consistent with this, there is an argument/adjunct asymmetry in Nêhiyawêwin, which in turn bears on the question of where overt arguments are positioned in a polysynthetic language. I argue that complement clauses are basê-generated in an A-position, unlike overt DPs which are in an A'-position (adjoined to IP). This explains why long-distance extraction is possible from complement clauses, while extraction from adjunct clauses is ungrammatical. Another property of wh-chains is their sensitivity to Weak Crossover (WCO). WCO effects are absent in Nêhiyawêwin wh-questions. I argue that WCO may be avoided because there is no movement of a truly quantificational operator in the sense of Lasnik and Stowell (1991), but rather movement of a null operator. I then propose a Weakest Crossover analysis for the absence of WCO, following Demirdache (1997).
Letter from J. E. [John Edgar] McAllister to Mr. [James] Goldie, May 12, 1916
Creators: name: McAllister, John Edgar
Publisher: name: The University of British Columbia
Year: 2017

description: Letter to Mr. [James] Goldie from J. E. [John Edgar] McAllister, dated May 12, 1916, regarding business, finances, and R. A. Lambert.
Magneto-electric properties and low-energy excitations of multiferroic FeCr2S4
Creators: name: Strinic, A.
name: Reschke, S.
name: Vasin, K. V.
name: Schmidt, M.
name: Loidl, A.
name: Tsurkan, V.
name: Eremin, M. V.
name: Deisenhofer, J.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We report on the low-frequency optical excitations in the multiferroic ground state of polycrystalline FeCr2S4 in the frequency range 0.3-3~THz and their changes upon applying external magnetic fields up to 7~T. In the ground state below the orbital-ordering temperature T_OO=9K we observe the appearance of several new modes. By applying the external magnetic field parallel and perpendicular to the propagation direction of the THz radiation, we can identify the strongest absorptions to be of predominantly electric-dipole origin. We discuss these modes as the low-energy electronic excitations of the Fe^{2+} ions (3d^6, S=2) in an tetrahedral environment. The eigenfrequencies and relative intensities of these absorption lines are satisfactorily reproduced by our calculation assuming an effective exchange field of 12.8 cm-1 at the Fe^{2+}-ions sites. The direction of the exchange field is found to be slightly tilted out of the ab-plane. With our approach we can also describe previously reported results from Mössbauer studies and the order of magnitude of the electric polarisation induced by orbital and non-collinear spin ordering.
Locally Compact Quantum Groups. A von Neumann Algebra Approach
Creators: name: Van Daele, Alfons
Publisher: name: arXiv
Year: 2006
Subjects: subject: Operator Algebras (math.OA)
subject: FOS: Mathematics
subject: 46L65 (Primary), 22D25, 22D35 (Secondary)

description: In this paper, we give an alternative approach to the theory of locally compact quantum groups, as developed by Kustermans and Vaes. We develop the theory completely within the von Neumann algebra framework. At various points, we also do things differently. We have a different treatment of the antipode. We obtain the uniqueness of the Haar weights in an early stage. We take advantage of this fact when deriving the other main results in the theory. We also give a slightly different approach to duality. Finally, we collect, in a systematic way, several important formulas. In an appendix, we indicate very briefly how the $C^*$-approach and the von Neumann algebra approach eventually yield the same objects.
Signatures of $α$ clustering in $^{16}$O by using a multiphase transport model
Creators: name: Li, Yi-An
name: Zhang, Song
name: Ma, Yu-Gang
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: $α$-clustered structures in light nuclei could be studied through "snapshots" taken by relativistic heavy-ion collisions. A multiphase transport (AMPT) model is employed to simulate the initial structure of collision nuclei and the proceeding collisions at center of mass energy $\sqrt{s_{NN}}$ = 6.37 TeV. This initial structure can finally be reflected in the subsequent observations, such as elliptic flow ($v_{2}$), triangular flow ($v_{3}$) and quadrangular flow ($v_4$). Three sets of the collision systems are chosen to illustrate system scan is a good way to identify the exotic $α$-clustered nuclear structure, case I: $\mathrm{^{16}O}$ nucleus (with or without $α$-cluster) + ordinary nuclei (always in Woods-Saxon distribution) in most central collisions, case II: $\mathrm{^{16}O}$ nucleus (with or without $α$-cluster) + $\mathrm{^{197}Au}$ nucleus collisions for centrality dependence, and case III: symmetric collision systems (namely, $^{10}$B + $^{10}$B, $^{12}$C + $^{12}$C, $^{16}$O + $^{16}$O (with or without $α$-cluster), $^{20}$Ne + $^{20}$Ne, and $^{40}$Ca + $^{40}$Ca) in most central collisions. Our calculations propose that relativistic heavy-ion collision experiments at $\sqrt{s_{NN}}$ = 6.37 TeV are promised to distinguish the tetrahedron structure of $\mathrm{^{16}O}$ from the Woods-Saxon one and shed lights on the system scan projects in experiments.
description: 9 pages, 4 figures; accepted version of Physical Review C
Remnant Radio Galaxies Discovered in a Multi-frequency Survey
Creators: name: Quici, B.
name: Hurley-Walker, N.
name: Seymour, N.
name: Turner, R. J.
name: Shabala, S. S.
name: Huynh, M.
name: Andernach, H.
name: Kapińska, A. D.
name: Collier, J. D.
name: Johnston-Hollitt, M.
name: White, S. V.
name: Prandoni, I.
name: Galvin, T. J.
name: Franzen, T.
name: Ishwara-Chandra, C. H.
name: Bellstedt, S.
name: Tingay, S. J.
name: Gaensler, B. M.
name: O'Brien, A.
name: Rogers, J.
name: Chow, K.
name: Driver, S.
name: Robotham, A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The remnant phase of a radio galaxy begins when the jets launched from an active galactic nucleus are switched off. To study the fraction of radio galaxies in a remnant phase, we take advantage of a $8.31$\,deg$^2$ sub-region of the GAMA~23~field which comprises of surveys covering the frequency range 0.1--9\,GHz. We present a sample of 104 radio galaxies compiled from observations conducted by the Murchison Wide-field Array (216\,MHz), the Australia Square Kilometer Array Pathfinder (887\,MHz), and the Australia Telescope Compact Array (5.5\,GHz). We adopt an `absent radio core' criterion to identify 10 radio galaxies showing no evidence for an active nucleus. We classify these as new candidate remnant radio galaxies. Seven of these objects still display compact emitting regions within the lobes at 5.5\,GHz; at this frequency the emission is short-lived, implying a recent jet switch-off. On the other hand, only three show evidence of aged lobe plasma by the presence of an ultra-steep spectrum ($α
Run-and-Tumble particles in Two-dimensions under Stochastic Resetting
Creators: name: Santra, Ion
name: Basu, Urna
name: Sabhapandit, Sanjib
Publisher: name: arXiv
Year: 2020
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We study the effect of stochastic resetting on a run and tumble particle (RTP) in two spatial dimensions. We consider a resetting protocol which affects both the position and orientation of the RTP: with a constant rate the particle undergoes a positional resetting to a fixed point in space and orientation randomization. We compute the radial and $x$-marginal stationary state distributions and show that while the former approaches a constant value as $r \to 0$, the latter diverges logarithmically as $x \to 0$. On the other hand, both the marginal distributions decay exponentially with the same exponent far away from the origin. We also study the temporal relaxation of the RTP and show that the position distribution undergoes a dynamical transition to a stationary state. We also study the first passage properties of the RTP in the presence of the resetting and show that the optimization of the resetting rate can minimize the mean first passage time. We also give a brief discussion on the stationary states for resetting to the initial position with fixed orientation.
description: 26 pages
A New Estimate of the Hubble Time with Improved Modeling of Gravitational Lenses
Creators: name: Coles, Jonathan
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: This paper examines free-form modeling of gravitational lenses using Bayesian ensembles of pixelated mass maps. The priors and algorithms from previous work are clarified and significant technical improvements are made. Lens reconstruction and Hubble Time recovery are tested using mock data from simple analytic models and recent galaxy-formation simulations. Finally, using published data, the Hubble Time is inferred through the simultaneous reconstruction of eleven time-delay lenses. The result is H_0^{-1}=13.7^{+1.8}_{-1.0} Gyr.
description: 24 pages, 9 figures. Accepted to ApJ
PSORALEA DRUPACEAE BUNGE (PSORALEA KOSTYANKOVA OR AKKURAI) CHEMICAL COMPOSITION AND APPLICATION IN MEDICINE
Creators: name: Abdujabborova, Charoskhan
Publisher: name: Zenodo
Year: 2024

description: This article talks about the morphology, chemical composition, pharmacology of scientific research and its use in folk medicine of the Psoralea drupaceae Bunge (Oqquray) plant found in Uzbekistan.
On the eigenvector bias of Fourier feature networks: From regression to solving multi-scale PDEs with physics-informed neural networks
Creators: name: Wang, Sifan
name: Wang, Hanwen
name: Perdikaris, Paris
Publisher: name: arXiv
Year: 2020
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: Physics-informed neural networks (PINNs) are demonstrating remarkable promise in integrating physical models with gappy and noisy observational data, but they still struggle in cases where the target functions to be approximated exhibit high-frequency or multi-scale features. In this work we investigate this limitation through the lens of Neural Tangent Kernel (NTK) theory and elucidate how PINNs are biased towards learning functions along the dominant eigen-directions of their limiting NTK. Using this observation, we construct novel architectures that employ spatio-temporal and multi-scale random Fourier features, and justify how such coordinate embedding layers can lead to robust and accurate PINN models. Numerical examples are presented for several challenging cases where conventional PINN models fail, including wave propagation and reaction-diffusion dynamics, illustrating how the proposed methods can be used to effectively tackle both forward and inverse problems involving partial differential equations with multi-scale behavior. All code an data accompanying this manuscript will be made publicly available at \url{https://github.com/PredictiveIntelligenceLab/MultiscalePINNs}.
description: 27 pages, 18 figures
An innovative integral field unit upgrade with 3D-printed micro-lenses for the RHEA at Subaru
Creators: name: Anagnos, Theodoros
name: Maier, Pascal
name: Hottinger, Philipp
name: Betters, Chris
name: Feger, Tobias
name: Leon-Saval, Sergio G.
name: Gris-Sánchez, Itandehui
name: Yerolatsitis, Stephanos
name: Lozi, Julien
name: Birks, Tim A.
name: Vievard, Sebastian
name: Jovanovic, Nemanja
name: Rains, Adam D.
name: Ireland, Michael J.
name: Harris, Robert J.
name: Tiong, Blaise C. Kuo
name: Guyon, Olivier
name: Norris, Barnaby
name: Haffert, Sebastiaan Y.
name: Blaicher, Matthias
name: Xu, Yilin
name: Straub, Moritz
name: Pott, Jörg-Uwe
name: Sawodny, Oliver
name: Neureuther, Philip L.
name: Coutts, David W.
name: Schwab, Christian
name: Koos, Christian
name: Quirrenbach, Andreas
Publisher: name: arXiv
Year: 2021
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: In the new era of Extremely Large Telescopes (ELTs) currently under construction, challenging requirements drive spectrograph designs towards techniques that efficiently use a facility's light collection power. Operating in the single-mode (SM) regime, close to the diffraction limit, reduces the footprint of the instrument compared to a conventional high-resolving power spectrograph. The custom built injection fiber system with 3D-printed micro-lenses on top of it for the replicable high-resolution exoplanet and asteroseismology spectrograph at Subaru in combination with extreme adaptive optics of SCExAO, proved its high efficiency in a lab environment, manifesting up to ~77% of the theoretical predicted performance.
N=1/2 Supersymmetric gauge theory in noncommutative space
Creators: name: Dayi, O. F.
name: Kelleyane, L. T.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: A formulation of (non-anticommutative) N=1/2 supersymmetric U(N) gauge theory in noncommutative space is studied. We show that at one loop UV/IR mixing occurs. A generalization of Seiberg-Witten map to noncommutative and non-anticommutative superspace is employed to obtain an action in terms of commuting fields at first order in the noncommutativity parameter tetha. This leads to abelian and non-abelian gauge theories whose supersymmetry transformations are local and non-local, respectively.
description: One reference added, published version