cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Detailed Chemical Abundances of Globular Clusters in Local Group Dwarf Galaxies
Creators: name: Colucci, J. E.
name: Bernstein, R. A.
name: McWilliam, A.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We present detailed chemical abundances of Fe, Ca and Ba for 17 globular clusters (GCs) in 5 Local Group dwarf galaxies: NGC 205, NGC 6822, WLM, the SMC and LMC. These abundances are part of a larger sample of over 20 individual elements measured in GCs in these galaxies using a new analysis method for high resolution, integrated light spectra. Our analysis also provides age and stellar population constraints. The existence of GCs in dwarf galaxies with a range of ages implies that there were episodes of rapid star formation throughout the history of these galaxies; the abundance ratios of these clusters suggest that the duration of these burst varied considerably from galaxy to galaxy. We find evolution of Fe, Ca, and Ba with age in the LMC, SMC, and NGC 6822 that is consistent with extended, lower-efficiency SF between bursts, with an increasing contribution of low-metallicity AGB ejecta at late times. Our sample of GCs in NGC 205 and WLM are predominantly old and metal-poor with high [Ca/Fe] ratios, implying that the early history of these galaxies was marked by consistently high SF rates.
description: 2 pages, To appear in the proceedings of the conference "A Universe of Dwarf Galaxies" (Lyon, June 14-18, 2010)
Fourth moments reveal the negativity of the Wigner function
Creators: name: Bednorz, Adam
name: Belzig, Wolfgang
Publisher: name: arXiv
Year: 2011
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The presence of unique quantum correlations is the core of quantum information processing and general quantum theory. We address the fundamental question of how quantum correlations of a generic quantum system can be probed using correlation functions defined for quasiprobability distributions. In particular we discuss the possibility of probing the negativity of a quasiprobability by comparing moments of the Wigner function. We show that one must take at least the fourth moments to find the negativity in general and the eighth moments for states with a rotationally invariant Wigner function.
description: 5 pages, published version
SDWFS-MT-1: A Self-Obscured Luminous Supernova at z~0.2
Creators: name: Kozlowski, Szymon
name: Kochanek, C. S.
name: Stern, D.
name: Prieto, J. L.
name: Stanek, K. Z.
name: Thompson, T. A.
name: Assef, R. J.
name: Drake, A. J.
name: Szczygiel, D. M.
name: Wozniak, P. R.
name: Nugent, P.
name: Ashby, M. L. N.
name: Beshore, E.
name: Brown, M. J. I.
name: Dey, Arjun
name: Griffith, R.
name: Harrison, F.
name: Jannuzi, B. T.
name: Larson, S.
name: Madsen, K.
name: Pilecki, B.
name: Pojmanski, G.
name: Skowron, J.
name: Vestrand, W. T.
name: Wren, J. A.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We report the discovery of a six-month-long mid-infrared transient, SDWFS-MT-1 (aka SN 2007va), in the Spitzer Deep, Wide-Field Survey of the NOAO Deep Wide-Field Survey Bootes field. The transient, located in a z=0.19 low luminosity (M_[4.5]~-18.6 mag, L/L_MilkyWay~0.01) metal-poor (12+log(O/H)~7.8) irregular galaxy, peaked at a mid-infrared absolute magnitude of M_[4.5]~-24.2 in the 4.5 micron Spitzer/IRAC band and emitted a total energy of at least 10^51 ergs. The optical emission was likely fainter than the mid-infrared, although our constraints on the optical emission are poor because the transient peaked when the source was "behind" the Sun. The Spitzer data are consistent with emission by a modified black body with a temperature of ~1350 K. We rule out a number of scenarios for the origin of the transient such as a Galactic star, AGN activity, GRB, tidal disruption of a star by a black hole and gravitational lensing. The most plausible scenario is a supernova exploding inside a massive, optically thick circumstellar medium, composed of multiple shells of previously ejected material. If the proposed scenario is correct, then a significant fraction (~10%) of the most luminous supernova may be self-enshrouded by dust not only before but also after the supernova occurs. The spectral energy distribution of the progenitor of such a supernova would be a slightly cooler version of eta Carina, peaking at 20-30 microns.
description: 26 pages, 5 figures, 1 table, accepted for publication in ApJ
Electromagnetic signatures of a strongly coupled anisotropic plasma
Creators: name: Rebhan, Anton
name: Steineder, Dominik
Publisher: name: arXiv
Year: 2011
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: In heavy-ion collisions, quark-gluon plasma is likely to be produced with sizable initial pressure anisotropy, which may leave an imprint on electromagnetic observables. In order to model a strongly coupled anisotropic plasma, we use the AdS/CFT correspondence to calculate the current-current correlator of a weakly gauged U(1) subgroup of R symmetry in an N=4 super-Yang-Mills plasma with a (temporarily) fixed anisotropy. The dual geometry, obtained previously by Janik and Witaszczyk, contains a naked singularity which however permits purely infalling boundary conditions and therefore the usual definition of a retarded correlator. We obtain numerical results for the cases of wave vector parallel and orthogonal to the direction of anisotropy, and we compare with previous isotropic results. In the (unphysical) limit of vanishing frequency (infinite time) we obtain a vanishing DC conductivity for any amount of anisotropy, but the anisotropic AC conductivities smoothly approach the isotropic case in the limit of high frequencies. We also discuss hard photon production from an anisotropic plasma and compare with existing hard-loop resummed calculations.
description: 23 pages, 15 figures. v3: improved figures 1 and 3
Improved nuclear matter calculations from chiral low-momentum interactions
Creators: name: Hebeler, K.
name: Bogner, S. K.
name: Furnstahl, R. J.
name: Nogga, A.
name: Schwenk, A.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We present new nuclear matter calculations based on low-momentum interactions derived from chiral effective field theory potentials. The current calculations use an improved treatment of the three-nucleon force contribution that includes a corrected combinatorial factor beyond Hartree-Fock that was omitted in previous nuclear matter calculations. We find realistic saturation properties using parameters fit only to few-body data, but with larger uncertainty estimates from cutoff dependence and the 3NF parametrization than in previous calculations.
description: 5 pages, 4 figures
Forward Instrumentation for ILC Detectors
Creators: name: Abramowicz, Halina
name: Abusleme, Angel
name: Afanaciev, Konstantin
name: Aguilar, Jonathan
name: Ambalathankandy, Prasoon
name: Bambade, Philip
name: Bergholz, Matthias
name: Bozovic-Jelisavcic, Ivanka
name: Castro, Elena
name: Chelkov, Georgy
name: Coca, Cornelia
name: Daniluk, Witold
name: Dragone, Angelo
name: Dumitru, Laurentiu
name: Elsener, Konrad
name: Emeliantchik, Igor
name: Fiutowski, Tomasz
name: Gostkin, Mikhail
name: Grah, Christian
name: Grzelak, Grzegorz
name: Haller, Gunter
name: Henschel, Hans
name: Ignatenko, Alexandr
name: Idzik, Marek
name: Ito, Kazutoshi
name: Jovin, Tatjana
name: Kielar, Eryk
name: Kotula, Jerzy
name: Krumstein, Zinovi
name: Kulis, Szymon
name: Lange, Wolfgang
name: Lohmann, Wolfgang
name: Levy, Aharon
name: Moszczynski, Arkadiusz
name: Nauenberg, Uriel
name: Novgorodova, Olga
name: Ohlerich, Marin
name: Orlandea, Marius
name: Oleinik, Gleb
name: Oliwa, Krzysztof
name: Olshevski, Alexander
name: Pandurovic, Mila
name: Pawlik, Bogdan
name: Przyborowski, Dominik
name: Sato, Yutaro
name: Sadeh, Iftach
name: Sailer, Andre
name: Schmidt, Ringo
name: Schumm, Bruce
name: Schuwalow, Sergey
name: Smiljanic, Ivan
name: Swientek, Krzysztof
name: Takubo, Yosuke
name: Teodorescu, Eliza
name: Wierba, Wojciech
name: Yamamoto, Hitoshi
name: Zawiejski, Leszek
name: Zhang, Jinlong
Publisher: name: arXiv
Year: 2010
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: Two special calorimeters are foreseen for the instrumentation of the very forward region of the ILC detector, a luminometer designed to measure the rate of low angle Bhabha scattering events with a precision better than 10-3 and a low polar angle calorimeter, adjacent to the beam-pipe. The latter will be hit by a large amount of beamstrahlung remnants. The amount and shape of these depositions will allow a fast luminosity estimate and the determination of beam parameters. The sensors of this calorimeter must be radiation hard. Both devices will improve the hermeticity of the detector in the search for new particles. Finely segmented and very compact calorimeters will match the requirements. Due to the high occupancy fast front-end electronics is needed. The design of the calorimeters developed and optimised with Monte Carlo simulations is presented. Sensors and readout electronics ASICs have been designed and prototypes are available. Results on the performance of these major components are summarised.
description: 30 pages, 28 figures
Effects of hyperlipidemia on dysferlin- and dystrophin-deficient muscular dystrophies in double-disease mouse models
Creators: name: Milad, Nadia
Publisher: name: University of British Columbia
Year: 2018

description: Muscular dystrophy (MD) is a class of diseases marked by progressive muscle wasting and impaired ambulatory function. Dysferlin- and dystrophin-deficiencies lead to MD and both are expressed in myofibers as well as smooth muscle and endothelial cells lining the vasculature, suggesting vascular function may be a contributing factor to muscle pathology seen in MD. However, murine models of MD develop only mild pathology compared to patients, making therapeutic drug development challenging. Since mice are known to have endogenously low lipid levels and superior vascular health, disrupted vascular function may be aggravating MD progression in humans. We seek to investigate the effect of impaired vascular function on MD pathology through the generation and characterization of doubledisease murine models affected by both hyperlipidemia and MD. Firstly, the dysferlin-null (Dysf-KO) model of limb-girdle type 2B MD (LGMD2B) and the dystrophin-null (mdx) model of Duchenne MD (DMD) were crossed with apolipoprotein E-KO (ApoE-KO) hyperlipidemia model to generate Dysf-ApoE and Mdx-ApoE double-knockout mice (DKO). To further confirm the effects vascular disease on MD using a more human-relevant model, the Dysf-KO model was also crossed with the milder low-density-lipoprotein receptor-knockout (LDLRKO) model of hyperlipidemia. Significant worsening of ambulatory function and muscle pathology was observed in the Dysf-ApoE DKO model, displaying reduced stride length, sometimes complete loss of ambulation, and increased muscle wasting, necrosis, fibrosis and fat infiltration. Although the Mdx-ApoE model showed no exacerbation of ambulation decline, significant worsening of muscle necrosis and fibrofatty replacement was observed in MdxApoE DKO mice. However, few Dysf-LDLR DKOs were produced; all were maloccluded runts with abnormal gait, though without observable muscle pathology upon histological analysis. In all, the Dysf-ApoE and Mdx-ApoE mice demonstrate that hyperlipidemia and associated vascular disease can dramatically aggravate muscle pathology in MD. These double-disease models mimic more closely the severity of human MD and may be useful for evaluating therapeutic interventions. In addition, these data suggest that lipid-lowering and vascular-targeted therapies may be beneficial in LGMD2B and DMD.
Fast generation of ensembles of cosmological N-body simulations via mode-resampling
Creators: name: Schneider, Michael D.
name: Cole, Shaun
name: Frenk, Carlos S.
name: Szapudi, Istvan
Publisher: name: arXiv
Year: 2011
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We present an algorithm for quickly generating multiple realizations of N-body simulations to be used, for example, for cosmological parameter estimation from surveys of large-scale structure. Our algorithm uses a new method to resample the large-scale (Gaussian-distributed) Fourier modes in a periodic N-body simulation box in a manner that properly accounts for the nonlinear mode-coupling between large and small scales. We find that our method for adding new large-scale mode realizations recovers the nonlinear power spectrum to sub-percent accuracy on scales larger than about half the Nyquist frequency of the simulation box. Using 20 N-body simulations, we obtain a power spectrum covariance matrix estimate that matches the estimator in Takahashi et al. (2009) (from 5000 simulations) with < 20% errors in all matrix elements. Comparing the rates of convergence, we determine that our algorithm requires ~ 8 times fewer simulations to achieve a given error tolerance in estimates of the power spectrum covariance matrix. The degree of success of our algorithm indicates that we understand the main physical processes that give rise to the correlations in the matter power spectrum. Namely, the large-scale Fourier modes modulate both the degree of structure growth through the variation in the effective local matter density and also the spatial frequency of small-scale perturbations through large-scale displacements. We expect our algorithm to be useful for noise modeling when constraining cosmological parameters from weak lensing (cosmic shear) and galaxy surveys, rescaling summary statistics of N-body simulations for new cosmological parameter values, and any applications where the influence of Fourier modes larger than the simulation size must be accounted for.
description: 13 pages, 11 figures. Matches version accepted for publication in ApJ. New panel in fig. 11 showing the covariance convergence rate with the number of mode resamplings
Letter of endorsement by Charles Dollard for Gunnar Myrdal and Richard Sterner, July 2, 1942
Creators: name: Dollard, Charles, 1907-1977
Publisher: name: Columbia University
Year: 2019
Subjects: Race relations
African Americans--Social conditions
Endowments

description: Letter written by Charles Dollard at the request of Frederick P. Keppel on behalf of Gunnar Myrdal and Richard Sterner, describing their work on the Carnegie-Myrdal Study and requesting assistance in facilitating their safe return to Sweden in September, 1942.
Memorandum to Charles Dollard, July 6 to 13, 1942
Creators: name: (:Unav)
Publisher: name: Columbia University
Year: 2019
Subjects: Race relations
African Americans--Social conditions
Endowments

description: Notes from meetings between Charles Dollard, Frederick P. Keppel, Louis Wirth and Edward L. Thorndike regarding Gunnar Myrdal's manuscript for the Carnegie-Myrdal Study.
Massive Color-Octet Bosons: Bounds on Effects in Top-Quark Pair Production
Creators: name: Haisch, Ulrich
name: Westhoff, Susanne
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: A critical survey of the existing direct and indirect constraints on massive spin-one color octets is presented. Since such new degrees of freedom appear in any extension of the color gauge group to a product of at least two SU(3) factors, we keep our discussion as independent as possible from the underlying theory. In the framework of scenarios that involve flavor non-universal couplings, we show that excessive flavor-changing neutral currents can be avoided by a suitable alignment in flavor space. Constraints from electroweak precision observables and direct production at hadron colliders still leave space for sizable new-physics effects in top-quark pair production, in particular a large forward-backward asymmetry. In this context, we derive a model-independent upper bound on the asymmetry that applies whenever top-antitop production receives the dominant corrections from s-channel exchange of a new single color-octet resonance.
description: v2: matches version published in JHEP
A Geometric Approach to CP Violation: Applications to the MCPMFV SUSY Model
Creators: name: Ellis, John
name: Lee, Jae Sik
name: Pilaftsis, Apostolos
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We analyze the constraints imposed by experimental upper limits on electric dipole moments (EDMs) within the Maximally CP- and Minimally Flavour-Violating (MCPMFV) version of the MSSM. Since the MCPMFV scenario has 6 non-standard CP-violating phases, in addition to the CP-odd QCD vacuum phase θ_QCD, cancellations may occur among the CP-violating contributions to the three measured EDMs, those of the Thallium, neutron and Mercury, leaving open the possibility of relatively large values of the other CP-violating observables. We develop a novel geometric method that uses the small-phase approximation as a starting point, takes the existing EDM constraints into account, and enables us to find maximal values of other CP-violating observables, such as the EDMs of the Deuteron and muon, the CP-violating asymmetry in b --> s γdecay, and the B_s mixing phase. We apply this geometric method to provide upper limits on these observables within specific benchmark supersymmetric scenarios, including extensions that allow for a non-zero θ_QCD.
description: 34 pages, 16 eps figures, to appear in JHEP
Classification of 3D consistent quad-equations
Creators: name: Boll, Raphael
Publisher: name: arXiv
Year: 2010
Subjects: subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: FOS: Physical sciences

description: We consider 3D consistent systems of six independent quad-equations assigned to the faces of a cube. The well-known classification of 3D consistent quad-equations, the so-called ABS-list, is included in this situation. The extension of these equations to the whole lattice Z^3 is possible by reflecting the cubes. For every quad-equation we will give at least one system included leading to a Bäcklund transformation and a zero-curvature representation which means that they are integrable.
description: 31 pages
A Universal Lower Bound on the Specific Temperatures of AdS-Reissner-Nordstrom Black Holes with Flat Event Horizons
Creators: name: McInnes, Brett
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We show that, in a gravitational theory [in any number of dimensions greater than 3] which admits BPS branes and AdS-Reissner-Nordstrom black holes with flat event horizons, the specific [dimensionless] temperature of such a black hole is bounded below by approximately 0.156875. This confirms the recent suggestion by Hartnoll and Tavanfar, to the effect that no such black hole can be arbitrarily cold, since from the AdS/CFT dual point of view the low-temperature degrees of freedom should not be concealed by the equivalent of an event horizon.
description: Discussion of brane action greatly improved in response to suggestion by referee; version to appear in Nuclear Physics B; 18 pages, one diagram
Novel anticoagulant neutralizing agents for the management of bleeding : studies on the design, mechanism of action and their influence on blood coagulation
Creators: name: Kalathottukaren, Manu Thomas
Publisher: name: University of British Columbia
Year: 2020

description: Heparins exert anticoagulation by potentiating anti-factor (F)Xa and anti-thrombin activity of antithrombin (AT), whereas oral anticoagulants (DOACs) directly target FXa or thrombin. FXa and thrombin are the key proteases required for blood clotting. Anticoagulants are therefore used for the prophylaxis and treatment of thrombosis and during surgeries. However, anticoagulation associated haemorrhage is a concern. The only approved antidote for unfractionated heparin (UFH), protamine do have limitations including cardiovascular complications. No approved antidotes are available for low molecular weight heparins, fondaparinux and direct FXa inhibitors. Therefore, there is a need for antidotes that are nontoxic and efficient. In this thesis, we reveal the mechanism of action, hemocompatibility and efficiency of three antidote molecules that are under development. UHRA: UHRA is a synthetic antidote developed by the Kizhakkedathu laboratory at the UBC. Thermodynamics based on isothermal titration calorimetry (ITC) and fluorescence studies revealed the molecular design of UHRA, the importance of steric shield produced by PEG brush, the selectivity of UHRA against heparins and its mechanism of action. Clotting studies confirm the antidote activity of UHRA. Studies also show that UHRA even in the absence of heparins, do not interact with fibrinogen, alter fibrin polymerization or abrogate blood clotting. Unlike protamine, UHRA does not incorporate into blood clots, form clots with normal morphology, and lysis profile. Studies in mice reveal that UHRA reverses UFH anticoagulant activity without the lung injury as seen with protamine. Studies confirm the superiority of UHRA compared to protamine. Andexanet Alfa (AnXa) and PER977: AnXa is a truncated FXa recombinant protein developed by Portola Pharmaceuticals and PER977 is a small cationic molecule developed by Perosphere Pharmaceuticals. ITC confirms high-affinity binding of AnXa to heparin/AT complex and to DOACs studied. PER977 shows weak binding to heparins and no binding to DOACs tested. Both antidotes do not influence fibrin polymerization, fibrin and blood clot architecture even in the absence of anticoagulants. Electron micrographs of blood clots containing edoxaban treated with AnXa or PER977 reveal restoration of impaired fibrin formation. However, in clotting assays, PER977 failed to show antidote activity, whereas AnXa neutralized the anticoagulation activity of all tested anticoagulants.
Generation of Coherent Structures After Cosmic Inflation
Creators: name: Gleiser, Marcelo
name: Graham, Noah
name: Stamatopoulos, Nikitas
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We investigate the nonlinear dynamics of hybrid inflation models, which are characterized by two real scalar fields interacting quadratically. We start by solving numerically the coupled Klein-Gordon equations in static Minkowski spacetime, searching for possible coherent structures. We find long-lived, localized configurations, which we identify as a new kind of oscillon. We demonstrate that these two-field oscillons allow for "excited" states with much longer lifetimes than those found in previous studies of single-field oscillons. We then solve the coupled field equations in an expanding Friedmann-Robertson-Walker spacetime, finding that as the field responsible for inflating the Universe rolls down to oscillate about its minimum, it triggers the formation of long-lived two-field oscillons, which can contribute up to 20% of the total energy density of the Universe. We show that these oscillons emerge for a wide range of parameters consistent with WMAP 7-year data. These objects contain total energy of about 25*10^20 GeV, localized in a region of approximate radius 6*10^-26 cm. We argue that these structures could have played a key role during the reheating of the Universe.
description: 12 pages, 10 .pdf figures, uses RevTex4; v2: expanded discussion in section IV, accepted for publication in Phys.Rev. D. Results remain the same
Phase diagram of chiral quark matter: color and electrically neutral Fulde-Ferrell phase
Creators: name: Huang, Xu-Guang
name: Sedrakian, Armen
Publisher: name: arXiv
Year: 2010
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The phase diagram of charge and color neutral two-flavor color superconducting quark matter is studied including the homogeneous two-flavor superconductor (2SC) and the inhomogeneous Fulde-Ferrell (FF) phases within the Nambu-Jona-Lasinio model. The low-temperature domain T < 5 MeV of the phase diagram contains the FF phase, which borders at high temperatures to the 2SC phase. The critical temperature of phase transition from the 2SC to the unpaired state is in the range 20-30 MeV. We derive the equation of state of matter and its composition and show that matter in mature compact stars should be in the inhomogeneous FF-like superconducting state. We briefly discuss the astrophysical implications of such a phase in compact stars.
description: v2: typos corrected, 8 pages, 1 figure; v3: minor corrections, matches published version
The effects due to hadronization in the inclusive tau lepton decay
Creators: name: Nesterenko, A. V.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Theoretical description of inclusive tau lepton hadronic decay is performed in the framework of Dispersive approach to QCD. The significance of effects due to hadronization is demonstrated. The approach on hand is capable of describing experimental data on tau lepton decay in vector and axial-vector channels. The vicinity of values of QCD scale parameter obtained in both channels testifies to the self-consistency of developed approach.
description: Talk given at Eleventh Workshop on Nonperturbative QCD, 6 - 10 June 2011, Paris, France; 10 pages, 4 figures
Opportunities and challenges in the use of heavily doped polycrystalline silicon as a thermoelectric material. An experimental study
Creators: name: Narducci, Dario
name: Selezneva, Ekaterina
name: Cerofolini, Gianfranco
name: Romano, Elisabetta
name: Tonini, Rita
name: Ottaviani, Giampiero
Publisher: name: arXiv
Year: 2010
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: Large-volume deployment of Si-based Seebeck generators can be foreseen only if polycrystalline rather than single crystalline materials can be actually used. The aim of this study was therefore to verify whether polycrystalline Si films deposited on top of a SiO$_2$ insulating layer can develop interesting thermoelectric power factors. We prepared 450-nm thick heavily boron doped polysilicon layers, setting the initial boron content in the film to be in excess of the boron solubility in polycrystalline silicon at 1000 °C. Isochronal thermal annealings were then used to modify the B$_{Si}$ content by precipitation. Quite unexpectedly, a concurrent increase of the thermoelectric power and of the conductivity was observed for heat treatments at temperatures above 800 °C. Upon annealing at 1000 °C we found a power factor $P$ of 13 mW K$^{-2}$ m$^{-1}$, more than three times higher than previously reported $P$ for Si nanowires. These findings could be explained observing that degenerate polysilicon displays a remarkable enhancement of its Seebeck coefficient as an effect of the large amount of boron it can dissolve. Band gap narrowing and band tailing modify the density of states around the Fermi energy leading to a dramatic improvement of its log-derivative in the Mott equation. These results apparently point out an interesting direction for the development of Seebeck and Peltier devices sharing low cost and relatively high efficiency.
description: 6 pages, 6 figures. To be presented at the 8th European Conference on Thermoelectrics, Como, Italy, 22-24 September 2010 http://www.centrovolta.org/ECT2010/ A few typos fixed
Letter from E. Franklin Frazier to Gunnar Myrdal, July 6, 1942
Creators: name: Frazier, E. Franklin, 1894-1962
Publisher: name: Columbia University
Year: 2019
Subjects: Race relations
African Americans--Social conditions
Endowments

description: E. Franklin Frazier's feedback on Gunnar Myrdal's manuscript for Parts V-VII of "An American Dilemma."
Impact of open abdomen and Vacuum Assisted Closure Device in surgical abdominal sepsis
Creators: name: Bleszynski, Michael Sean
Publisher: name: University of British Columbia
Year: 2017

description: Introduction: Surgical abdominal sepsis has traditionally been managed with by a single staged procedure, otherwise known as primary abdominal closure (PAC). An on demand laparotomy may be performed for post-operative clinical deterioration. Open abdomen and a planned re-laparotomy with vacuum assisted closure (VAC) is an alternate method to single staged procedure. Inflammatory cytokines can potentially help stratify severity of sepsis and guide surgical management. The objective of the study was to identify if inflammatory cytokines could differentiate between PAC and VAC. Secondary objectives were to see if cytokines could predict mortality and characterize longitudinal cytokine profiles during open abdomen management. Severity of disease between surgical groups was compared using the Acute Physiology and Chronic Health Assessment (APACHE)-IV predictive mortality rate (PMR) calculator. Methods: Prospective case series between December 2011 to June 2013. Patients were included if they met criteria of severe abdominal sepsis/septic shock requiring urgent source control laparotomy (SCL). Blood and peritoneal samples were obtained pre- and post-operatively at primary SCL in patients who underwent PAC and VAC management. Peritoneal fluid (PF) samples were obtained once the peritoneum was entered. Blood and peritoneal samples were obtained for re-look laparotomies in the VAC group. Samples were centrifuged within 1 hour and stored at -70 degrees Celsius. Samples were analyzed with a Human Cytokine 30-plex Panel and concentrations were reported as pg/ml. Results: 12 patients were included (4 PAC and 8 VAC). PF cytokine concentrations of IL 6, IL-17, IL-5 and HGF were significantly higher in VAC compared to PAC. Peritoneal fluid at primary SCL did not differentiate between survivors and non-survivors. Pre-operative serum RANTES was significantly elevated in survivors compared to non-survivors. Pre operative serum VEGF, IL-1b, FGF-b, IL-5, IL-4, IL-7 and post-operative serum VEGF, IL-7 differentiated between VAC survivors and non-survivors at second SCL. Conclusion: VAC management was utilized in patients with elevated peritoneal cytokines compared to single staged procedures. Increased peritoneal inflammatory cytokine concentrations in VAC represent a more severe degree of local sepsis. Pro and anti-inflammatory cytokines are both elevated in the early and late phases of surgical abdominal sepsis.
Multiscale Simulation of History Dependent Flow in Polymer Melt
Creators: name: Murashima, Takahiro
name: Taniguchi, Takashi
Publisher: name: arXiv
Year: 2010
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We have developed a new multiscale simulation technique to investigate history-dependent flow behavior of entangled polymer melt, using a smoothed particle hydrodynamics simulation with microscopic simulators that account for the dynamics of entangled polymers acting on each fluid element. The multiscale simulation technique is applied to entangled polymer melt flow around a circular obstacle in a two-dimensional periodic system. It is found that the strain-rate history-dependent stress of the entangled polymer melt affects its flow behavior, and the memory in the stress causes nonlinear behavior even in the regions where ${\rm Wi} \le 1$. The spatial distribution of the entanglements $$ is also investigated. The slightly low entanglement region is observed around the obstacle and is found to be broaden in the downstream region.
description: 4 pages, 3 figures
Contact! unload : a narrative study and filmic exploration of veterans performing stories of war and transition
Creators: name: McLean, Blair William
Publisher: name: University of British Columbia
Year: 2017

description: This study uses narrative methods and filmmaking to understand the experiences of six war veterans who performed "Contact! Unload," the theatre component of “Man, Art, Action,” a recent (2015/16) Movember-funded arts-based project, designed to engage veterans and the Canadian public with issues of military mental health. This research harnesses participants’ personal change narratives over the course of creating, rehearsing and performing Contact! Unload to understand therapeutic benefits for participants, to contribute to existing theories on action-oriented and theatre-based approaches to psychotherapy, and to inform a discussion of the needs of veterans in transition.
Search for Higgs Bosons in SUSY Cascade Decays and Neutralino Dark Matter
Creators: name: Gori, Stefania
name: Schwaller, Pedro
name: Wagner, Carlos E. M.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The Minimal Supersymmetric Extension of the Standard Model (MSSM) is a well motivated theoretical framework, which contains an extended Higgs sector, including a light Higgs with Standard Model-like properties in most of the parameter space. Due to the large QCD background, searches for such a Higgs, decaying into a pair of bottom quarks, is very challenging at the LHC. It has been long realized that the situation may be ameliorated by searching for Higgs bosons in supersymmetric decay chains. Moreover, it has been recently suggested that the bobber decay channel may be observed in standard production channels by selecting boosted Higgs bosons, which may be easily identified from the QCD background. Such boosted Higgs bosons are frequent in the MSSM, since they are produced from decays of heavy colored supersymmetric particles. Previous works have emphasized the possibility of observing boosted Higgs bosons in the light higgsino region. In this work, we study the same question in the regions of parameter space consistent with a neutralino dark matter relic density, analyzing its dependence on the non-standard Higgs boson, slepton and squark masses, as well as on the condition of gaugino mass unification. In general, we conclude that, provided sleptons are heavier than the second lightest neutralinos, the presence of boosted Higgs is a common MSSM feature, implying excellent prospects for observation of the light MSSM Higgs boson in the near future.
description: 30 pages, 9 figures. v2: New Xenon 100 results implemented, version to appear in PRD
title: Pulmonary arteriovenous malformation: Multimodality chest imaging
Creators: name: Yadav, Arzoo
Publisher: name: EURORAD
Year: 2023
Subjects: subject: Chest imaging
subject: Lung
subject: Pulmonary vessels
subject: Clinical Case

description: Clinical History: A 23-year-old female presented with a complaint of intermittent dyspnea (New York Heart Association NYHA grade, II), which aggravates on exertion and mild chest pain. No past significant medical and surgical history was given by the patient. On clinical examination, bruit was heard on auscultation in the left mid-zone.

description: 23 years, female
Slow dynamics and precursors of the glass transition in granular fluids
Creators: name: Gholami, Iraj
name: Fiege, Andrea
name: Zippelius, Annette
Publisher: name: arXiv
Year: 2011
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We use event driven simulations to analyze glassy dynamics as a function of density and energy dissipation in a two-dimensional bidisperse granular fluid under stationary conditions. Clear signatures of a glass transition are identified, such as an increase of relaxation times over several orders of magnitude. As the inelasticity is increased, the glass transition is shifted to higher densities and the precursors of the transition become less and less pronounced -- in agreement with a recent mode-coupling theory. We analyze the long-time tails of the velocity autocorrelation and discuss its consequences for the nonexistence of the diffusion constant in two dimensions.
description: 10 pages, 16 figures
Spatial and temporal tuning in void models for acceleration
Creators: name: Foreman, Simon
name: Moss, Adam
name: Zibin, James P.
name: Scott, Douglas
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: There has been considerable interest in recent years in cosmological models in which we inhabit a very large, underdense void as an alternative to dark energy. A longstanding objection to this proposal is that observations limit our position to be very close to the void centre. By selecting from a family of void profiles that fit supernova luminosity data, we carefully determine how far from the centre we could be. To do so, we use the observed dipole component of the cosmic microwave background, as well as an additional stochastic peculiar velocity arising from primordial perturbations. We find that we are constrained to live within 80 Mpc of the centre of a void--a somewhat weaker constraint than found in previous studies, but nevertheless a strong violation of the Copernican principle. By considering how such a Gpc-scale void would appear on the microwave sky, we also show that there can be a maximum of one of these voids within our Hubble radius. Hence, the constraint on our position corresponds to a fraction of the Hubble volume of order 10^{-8}. Finally, we use the fact that void models only look temporarily similar to a cosmological-constant-dominated universe to argue that these models are not free of temporal fine-tuning.
description: 7 pages, 4 figures; revised to match accepted version
Global uniqueness and reconstruction for the multi-channel Gel'fand-Calderón inverse problem in two dimensions
Creators: name: Novikov, Roman
name: Santacesaria, Matteo
Publisher: name: arXiv
Year: 2010
Subjects: subject: Analysis of PDEs (math.AP)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: We study the multi-channel Gel'fand-Calderón inverse problem in two dimensions, i.e. the inverse boundary value problem for the equation $-Δψ+ v(x) ψ= 0$, $x\in D$, where $v$ is a smooth matrix-valued potential defined on a bounded planar domain $D$. We give an exact global reconstruction method for finding $v$ from the associated Dirichlet-to-Neumann operator. This also yields a global uniqueness results: if two smooth matrix-valued potentials defined on a bounded planar domain have the same Dirichlet-to-Neumann operator then they coincide.
Vulnerability in the Canadian refugee determination arena : an interpretive description study
Creators: name: Huminuik, Kirby
Publisher: name: University of British Columbia
Year: 2017

description: This exploratory study utilized Interpretive Description, an applied qualitative methodology, to investigate the manner in which the concept of vulnerability is currently understood and intervened upon within the refugee determination arena in Canada. Consistent with Interpretive Description, this study generated qualitative data from multiple sources, which were theoretically and purposively selected. Four distinct source groups provided data at different levels of analysis: government documents and qualitative interviews with officials offered insight into the systemic level, key professional informants provided access to the organizational level, recent refugee claimants provided information on the individual level, and the collected documentation of a small number of refugee claims provided examples of particular instances, while providing insight into the refugee determination arena as a whole. In the context of Canadian refugee determination, ‘vulnerability’ refers to factors that impede access to a fair hearing and the risk of retraumatization. This study provides a rich and timely description of aspects of identity and experience that give rise to vulnerability for refugee claimants and the institutional and community-based practices that can exacerbate or mitigate risks for harm. Three key findings can be distilled from this study: vulnerability is conceptualized according to essentialized characteristics of refugee claimants, there is variation between professional conceptualizations of vulnerability, and there are barriers to implementation across the refugee determination arena. I argue that a mis-attribution of harm to the individual/intrapsychic rather than to the systemic domain, a lack of integration of the psychological knowledge base that underpins the concept of vulnerability, and systemic barriers to implementation result in less than optimal protection for refugee claimants.
Long Lived Fourth Generation and the Higgs
Creators: name: Keung, Wai-Yee
name: Schwaller, Pedro
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: A chiral fourth generation is a simple and well motivated extension of the standard model, and has important consequences for Higgs phenomenology. Here we consider a scenario where the fourth generation neutrinos are long lived and have both a Dirac and Majorana mass term. Such neutrinos can be as light as 40 GeV and can be the dominant decay mode of the Higgs boson for Higgs masses below the W-boson threshold. We study the effect of the Majorana mass term on the Higgs branching fractions and reevaluate the Tevatron constraints on the Higgs mass. We discuss the prospects for the LHC to detect the semi-invisible Higgs decays into fourth generation neutrino pairs. Under the assumption that the lightest fourth generation neutrino is stable, it's thermal relic density can be up to 20% of the observed dark matter density in the universe. This is in agreement with current constraints on the spin dependent neutrino-neutron cross section, but can be probed by the next generation of dark matter direct detection experiments.
description: v1: 19 pages, 5 figures; v2: References added; v3: version to appear in JHEP
Modularity of Convergence and Strong Convergence in Infinitary Rewriting
Creators: name: Kahrs, Stefan Michael
Publisher: name: arXiv
Year: 2010
Subjects: subject: Logic in Computer Science (cs.LO)
subject: Formal Languages and Automata Theory (cs.FL)
subject: FOS: Computer and information sciences
subject: F.4.2

description: Properties of Term Rewriting Systems are called modular iff they are preserved under (and reflected by) disjoint union, i.e. when combining two Term Rewriting Systems with disjoint signatures. Convergence is the property of Infinitary Term Rewriting Systems that all reduction sequences converge to a limit. Strong Convergence requires in addition that redex positions in a reduction sequence move arbitrarily deep. In this paper it is shown that both Convergence and Strong Convergence are modular properties of non-collapsing Infinitary Term Rewriting Systems, provided (for convergence) that the term metrics are granular. This generalises known modularity results beyond metric \infty.
Experimental mathematics techniques for Boolean functions and combinatorial games
Creators: name: Seidler, Blair
Publisher: name: No Publisher Supplied
Year: 2023

description: The theme of this dissertation is the application of experimental techniques to the analysis of Boolean functions and combinatorial games. The three projects comprising this paper all employ Zeilberger's overlapping stages methodology to build successively more efficient algorithms to mitigate the exponential growth of the combinatorial objects being studied.The first two projects concern Boolean functions. We produce a catalog of minimal functions for Boolean circuits of a small number of variables using straight-line programs as our representation of circuits. We then analyze the statistical moments of subcubes contained in Boolean functions, extending the work of Thanatipanonda. We also analyze mixed moments and the correlation between numbers of subcubes of various sizes. The third project analyzes the combinatorial game Juniper Green along with several new variations. Lemoine completely solved the problem of which initial positions of Juniper Green are winnable by the first player. We consider the Sprague-Grundy values of initial positions in the original game and variations.
Spacetime Geometry in Higher Spin Gravity
Creators: name: Ammon, Martin
name: Gutperle, Michael
name: Kraus, Per
name: Perlmutter, Eric
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Higher spin gravity is an interesting toy model of stringy geometry. Particularly intriguing is the presence of higher spin gauge transformations that redefine notions of invariance in gravity: the existence of event horizons and singularities in the metric become gauge dependent. In previous work, solutions of spin-3 gravity in the SL(3,R) x SL(3,R) Chern-Simons formulation were found, and were proposed to play the role of black holes. However, in the gauge employed there, the spacetime metric describes a traversable wormhole connecting two asymptotic regions, rather than a black hole. In this paper, we show explicitly that under a higher spin gauge transformation these solutions can be transformed to describe black holes with manifestly smooth event horizons, thereby changing the spacetime causal structure. A related aspect is that the Chern-Simons theory admits two distinct AdS_3 vacua with different asymptotic W-algebra symmetries and central charges. We show that these vacua are connected by an explicit, Lorentz symmetry-breaking RG flow, of which our solutions represent finite temperature generalizations. These features will be present in any SL(N,R) x SL(N,R) Chern-Simons theory of higher spins.
description: 33 pages, v2: references added, signs corrected
Possibility of measuring the thermal Casimir interaction between a plate and a cylinder attached to a micromachined oscillator
Creators: name: Decca, R. S.
name: Fischbach, E.
name: Klimchitskaya, G. L.
name: Krause, D. E.
name: Lopez, D.
name: Mostepanenko, V. M.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Quantum Physics (quant-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We investigate the possibility of measuring the thermal Casimir force and its gradient in the configuration of a plate and a microfabricated cylinder attached to a micromachined oscillator. The Lifshitz-type formulas in this configuration are derived using the proximity force approximation. The accuracy for the obtained expressions is determined from a comparison with exact results available in ideal metal case. Computations of the thermal correction to both the Casimir force and its gradient are performed in the framework of different theoretical approaches proposed in the literature. The correction to the Casimir force and its gradient due to lack of parallelism of the plate and cylinder is determined using the nonmultiplicative approach. The error introduced in the theory due to the finite length of the cylinder is estimated. We propose that both static and dynamic experiments measuring the thermal Casimir interaction between a cylinder and a plate using a micromachined oscillator can shed additional light on the thermal Casimir force problem. Specifically, it is shown that the static experiment is better adapted for the measurement of thermal effects.
description: 29 pages, 4 figures, 1 table; minor additions are made in accordance to the version accepted for publication; to appear in Phys. Rev. A