cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Spatially resolved H2 emission from the disk around T Tau N
Creators: name: Gustafsson, M.
name: Labadie, L.
name: Herbst, T. M.
name: Kasper, M.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report the detection of quiescent H2 emission in a spatially resolved ring-like structure within 100 AU of T Tau N. We present evidence to show that the emission most likely arises from shocks in the atmosphere of a nearly face-on disk around T Tau N. Using high spatial resolution 3D spectroscopic K-band data, we trace the spatial distribution of several H2 NIR rovibrational lines in the vicinity of T Tau N. We detect weak H2 emission from the v=1-0 S(0), S(1), Q(1) lines and the v=2-1 S(1) line in a ring-like structure around T Tau N between 0.1'' (~15 AU) and 0.7'' (~100AU) from the star. The v=1-0 S(0) and v=2-1 S(1) lines are detected only in the outer parts of the ring structure. Closer to the star, the strong continuum limits our sensitivity to these lines. The total flux of the v=1-0 S(1) line is 1.8 *10^{-14} ergs s^{-1}cm^{-2}, similar to previous measurements of H2 in circumstellar disks. The velocity of the H2 emitting gas around T Tau N is consistent with the rest velocity of the star, and the H2 does not seem to be part of a collimated outflow. Both shocks impinging on the surface of a disk and irradiation of a disk by UV-photons and X-rays from the central star are plausible candidates for the H2 excitation mechanism. However, irradiation should not create a large degree of excitation at radii larger than 20 AU. Most likely the H2 emission arises in the atmosphere of a flared disk with radius 85-100 AU and mass 0.005-0.5Msun, where the gas is excited by shocks created when a wide-angle wind impinges on the disk. The H2 emission could also originate from shock excitation in the cavity walls of an envelope, but this requires an unusually high velocity of the wide-angle wind from T Tau N.
description: Accepted by A&A
Laser-Cluster-Interaction in a Nanoplasma-Model with Inclusion of Lowered Ionization Energies
Creators: name: Hilse, Paul
name: Moll, Max
name: Schlanges, Manfred
name: Bornath, Thomas
Publisher: name: arXiv
Year: 2008
Subjects: subject: Atomic and Molecular Clusters (physics.atm-clus)
subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: The interaction of intense laser fields with silver and argon clusters is investigated theoretically using a modified nanoplasma model. Single pulse and double pulse excitations are considered. The influence of the dense cluster environment on the inner ionization processes is studied including the lowering of the ionization energies. There are considerable changes in the dynamics of the laser-cluster interaction. Especially, for silver clusters, the lowering of the ionization energies leads to increased yields of highly charged ions.
description: 10 pages, 11 figures
The Sun's Role for Decadal Climate Predictability in the North Atlantic
Creators: name: Drews, Annika
name: Wenjuan, Huo
name: Matthes, Katja
name: Kodera, Kunihiko
name: Kruschke, Tim
Publisher: name: Zenodo
Year: 2021

description: Workshop: Multi-annual to Decadal Climate Predictability in the North Atlantic-Arctic Sector
Practical long-distance quantum key distribution system using decoy levels
Creators: name: Rosenberg, D.
name: Peterson, C. G.
name: Harrington, J. W.
name: Rice, P. R.
name: Dallmann, N.
name: Tyagi, K. T.
name: McCabe, K. P.
name: Nam, S.
name: Baek, B.
name: Hadfield, R. H.
name: Hughes, R. J.
name: Nordholt, J. E.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Quantum key distribution (QKD) has the potential for widespread real-world applications. To date no secure long-distance experiment has demonstrated the truly practical operation needed to move QKD from the laboratory to the real world due largely to limitations in synchronization and poor detector performance. Here we report results obtained using a fully automated, robust QKD system based on the Bennett Brassard 1984 protocol (BB84) with low-noise superconducting nanowire single-photon detectors (SNSPDs) and decoy levels. Secret key is produced with unconditional security over a record 144.3 km of optical fibre, an increase of more than a factor of five compared to the previous record for unconditionally secure key generation in a practical QKD system.
description: 9 pages
The long Galactic bar as seen by UKIDSS Galactic Plane Survey
Creators: name: Cabrera-Lavers, A.
name: Gonzalez-Fernandez, C.
name: Garzon, F.
name: Hammersley, P. L.
name: Lopez-Corredoira, M.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Over the last decade there have been a series of results supporting the hypothesis of the existence of a long thin bar in the Milky Way with a half-length of 4.5 kpc and a position angle of around 45 deg. This is apparently a very different structure from the triaxial bulge of the Galaxy, which is thicker and shorter and dominates the star counts at |l|<10 deg. In this paper, we analyse the stellar distribution in the inner Galaxy to see if there is clear evidence for two triaxial or bar-like structures in the Milky Way. By using the red-clump population as a tracer of Galactic structure, we determine the apparent morphology of the inner Galaxy. Deeper and higher spatial resolution NIR photometry from the UKIDSS Galactic Plane Survey allows us to use in-plane data even at the innermost Galactic longitudes, a region where the source confusion is a dominant effect that makes it impossible to use other NIR databases such as 2MASS or TCS-CAIN. We show that results previously obtained with using the red-clump giants are confirmed with the in-plane data from UKIDSS GPS. There are two different structures coexisting in the inner Galactic plane: one with a position angle of 23.60+-2.19 deg that can be traced from the Galactic Centre up to l=10 deg (the Galactic bulge), and other with a larger position angle of 42.44+-2.14 deg, that ends around l=28 deg (the long Galactic bar).
description: (8 pages, 14 figures, accepted for publication in A&A)
title:  Aesthetics from the Interstices: The Making of a Home in a Palestinian Refugee Camp
Creators: name: van Emmerik  ,  Corine
Publisher: name: Roma TrE-Press
Year: 2021

description: This essay focuses on the making of a home as a ‘minor practice’. It focuses its attention on a family I met in a refugee camp in the West Bank and the ways in which they make space that acquires a certain permanence of home. How to make a home in a refugee camp suspended between different temporal and spatial worlds? Caught between the expulsion of Palestinians due to the 1948 Nakba or ‘catastrophe’, referring to the flight of Palestinian during the Arab-Israeli war, and the hope for the right of return, this essay aims to show how this refugee family, exiled in their own country, makes a home that, inspired by the Palestinian concept of Sumud, allows them to determine their own fate and joy despite the Occupation. I will take the reader on a tour through the house, in the same way as I was shown around in it, to demonstrate how the family generates their own space and home despite being haunted by trauma and memories of the Occupation, for example through the cultivation of a garden on their roof terrace. In this way, I will show how possibilities can be created from a liminal and marginal space such as the refugee camp and house in it through the ‘minor practice’ of home making, vectorising an everyday aesthetic-political quality that makes life felt.
description: Everydayness. Contemporary Aesthetic Approaches
The seesaw mechanism at TeV scale in the 3-3-1 model with right-handed neutrinos
Creators: name: Cogollo, D.
name: Diniz, H.
name: Pires, C. A. de S.
name: da Silva, P. S. Rodrigues
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We implement the seesaw mechanism in the 3-3-1 model with right-handed neutrinos. This is accomplished by the introduction of a scalar sextet into the model and the spontaneous violation of the lepton number. We identify the Majoron as a singlet under $SU_L(2)\otimes U_Y(1)$ symmetry, which makes it safe under the current bounds imposed by electroweak data. The main result of this work is that the seesaw mechanism works already at TeV scale with the outcome that the right-handed neutrino masses lie in the electroweak scale, in the range from MeV to tens of GeV. This window provides a great opportunity to test their appearance at current detectors, though when we contrast our results with some previous analysis concerning detection sensitivity at LHC, we conclude that further work is needed in order to validate this search.
description: about 13 pages, no figures
Sneutrino LSPs in R-parity violating minimal supergravity models
Creators: name: Bernhardt, Markus A.
name: Das, Siba Prasad
name: Dreiner, Herbi K.
name: Grab, Sebastian
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We consider the minimal supergravity model (mSUGRA) with one additional R-parity violating operator at the GUT scale. The superparticles mass spectra at the weak scale are generally altered due to the presence of the R-parity violating coupling in the renormalization group equations. We show that a lepton number violating coupling at the GUT scale can lead to a sneutrino as the lightest supersymmetric particle (LSP) in a large region of parameter space consistent with the muon anomalous magnetic moment and other precision measurements. We also give characteristic collider signatures at the LHC.
description: 3 pages, 3 figures, to appear in the proceedings of SUSY08, Seoul, Korea
Atom interferometry based on light pulses : application to the high precision measurement of the ratio h/m and the determination of the fine structure constant
Creators: name: Cadoret, Malo
name: De Mirandes, Estefania
name: Cladé, Pierre
name: Nez, François
name: Julien, Lucile
name: Biraben, François
name: Guellati-Khélifa, Saïda
Publisher: name: arXiv
Year: 2008
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: In this paper we present a short overview of atom interferometry based on light pulses. We discuss different implementations and their applications for high precision measurements. We will focus on the determination of the ratio h/m of the Planck constant to an atomic mass. The measurement of this quantity is performed by combining Bloch oscillations of atoms in a moving optical lattice with a Ramsey-Bordé interferometer.
Surprising dissimilarities in a newly formed pair of 'identical twin' stars
Creators: name: Stassun, Keivan G.
name: Mathieu, Robert D.
name: Cargile, Phillip A.
name: Aarnio, Alicia N.
name: Stempels, Eric
name: Geller, Aaron
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The mass and chemical composition of a star are the primary determinants of its basic physical properties--radius, temperature, luminosity--and how those properties evolve with time. Thus, two stars born at the same time, from the same natal material, and with the same mass are 'identical twins,' and as such might be expected to possess identical physical attributes. We have discovered in the Orion Nebula a pair of stellar twins in a newborn binary star system. Each star in the binary has a mass of 0.41 +/- 0.01 solar masses, identical to within 2 percent. Here we report that these twin stars have surface temperatures that differ by ~300K (~10%), and luminosities that differ by ~50%, both at high confidence level. Preliminary results indicate that the stars' radii also differ, by 5-10%. These surprising dissimilarities suggest that one of the twins may have been delayed by several hundred thousand years in its formation relative to its sibling. Such a delay could only have been detected in a very young, definitively equal-mass binary system3 such as that reported here. Our findings reveal cosmic limits on the age synchronisation of young binary stars, often used as tests for the age calibrations of star-formation models.
description: Published in Nature, 19 June 2008
The CaT strength in Seyfert nuclei revisited: analyzing young stars and non-stellar light contributions to the spectra
Creators: name: Vega, L. R.
name: Asari, N. V.
name: Fernandes, R. Cid
name: Garcia-Rissmann, A.
name: Storchi-Bergmann, T.
name: Delgado, R. M. Gonzalez
name: Schmitt, H.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: In a former paper (Garcia-Rissmann et al. 2005; hereafter Paper I), we have presented spectra of 64 active, 9 normal and 5 Starburst galaxies in the region around the near-IR Calcium triplet absorption lines and the [SIII]9069 line. In the present paper we analyze the CaT strength (WCaT), and kinematical products derived in that study, namely stellar and ionized gas velocity dispersions. Our main results may be summarized as follows: (1) Seyfert 2s show no sign of dilution in WCaT with respect to the values spanned by normal galaxies, even when optical absorption lines such as the CaII K band at 3933 A are much weaker than in old, bulge-like stellar populations. (2) The location of Seyfert 2s in the WCaT-WCaK plane is consistent with evolutionary synthesis models. The implication is that the source responsible for the dilution of optical lines in these AGN is a young stellar population, rather than an AGN featureless continuum, confirming the conclusion of the pioneer study of Terlevich, Diaz & Terlevich. (3) In Seyfert 1s, both W[SIII] and WCaT tend to be diluted due to the presence of a non-stellar component, in agreement with the unification paradigm. (4) A comparison of stellar and gas velocity dispersions confirms the existence of a correlation between the typical velocities of stars and clouds of the Narrow Line Region. The strength and scatter around this correlation are similar to those previously obtained from the [OIII]5007 line width.
description: 14 pages, 15 figures. Paper accepted for publication in MNRAS
UV Radiative Feedback During the Advanced Stages of Reionization
Creators: name: Mesinger, Andrei
name: Dijkstra, Mark
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The ionizing ultraviolet background (UVB) during reionization can suppress the gas content of low-mass galaxies, even those capable of efficient atomic cooling, and thus lead to an extended reionization epoch. In this work, we explore the importance of negative UV radiative feedback on Tvir > 10^4 K halos during the middle and late stages of reionization. We do not try to self-consistently model reionization; instead, we explore a large parameter space in an attempt to draw general, robust conclusions. We do this using a tiered approach. Using 1-D hydrodynamical simulations, we model the collapse of gas onto halos of various masses under UVBs of various intensities. We then generate realistic, parametrized maps of the inhomogeneous UVB, using large-scale semi-numeric simulations. By combining these results, we find that under all reasonably conservative scenarios, UV feedback on atomically-cooled halos is not strong enough to notably delay the bulk of reionization. Such a delay is only likely if ionizing efficiencies of z > 10 sources are much higher (~ two orders of magnitude) than z ~ 6 data seem to imply. We also find that feedback is very strongly dependent on halo mass. Our results suggest that the natural time-scale for the bulk of reionization is the growth of the global collapsed fraction contained in Tvir > 10^4 K halos. Finally, our results underscore the importance of taking into account extended dynamical ranges when modeling reionization.
description: 10 pages, 8 figures, MNRAS submitted
title: The Research School of Chemistry of Adolphe Wurtz, Paris, 1853-1884
Creators: name: Carneiro, Ana
Publisher: name: University of Kent
Year: 2021

description: Adolphe Wurtz (1817-1884) established a research school of chemistry in the Faculty of Medicine in Paris, which developed throughout the second half of the 19th century, acquiring an international reputation. Owing to particular circumstances, which relate both to his Alsation background and his internationalist ethos, Wurtz's school exhibited certain peculiarities which were in contrast with the current practice of the French scientific establishment and, in particular, with that of other leaders of research schools in Paris. In order to study this research group, a framework of analysis has been constructed, taking into account the origin of the school as a means of organising scientific research, and trying to understand its full meaning in the French context of the time. Thus, a brief account of the research schools of chemistry in Paris contemporary with that of Wurtz is given: the schools of Cahours, Sainte-Claire Deville, Pasteur and Berthelot. A detailed account of Wurtz's school of chemistry is then given, focussing on three major aspects: 1) Wurtz's personal, cultural and educational background, his ideology as well as his career both as a chemistry and as a member of Parisian scientific establishment; 2) his students in particular, their identification and national origins, their cultural and educational backgrounds, their interests, their involvement in Wurtz's school, the research areas and the publishing and institutional activities in which they took part, their publications and their careers; 3) finally, an analysis of the full meaning of the school: the research laboratory, its peculiar administration and routine; a comprehensive analysis of the foundations and development of both the theoretical and empirical aspects of Wurtz's research programme, especially in organic and biological chemistry, as well as the contributions of his students to the programme: an account of the activities in a wider context, focussing on scientific and educational institutions and publications, which were either launched, controlled or supported by Wurtz's school.
Kinematic and Dynamic Analyses of the Orthoglide 5-axis
Creators: name: Ur-Rehman, Raza
name: Caro, Stéphane
name: Chablat, Damien
name: Wenger, Philippe
Publisher: name: arXiv
Year: 2008
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: This paper deals with the kinematic and dynamic analyses of the Orthoglide 5-axis, a five-degree-of-freedom manipulator. It is derived from two manipulators: i) the Orthoglide 3-axis; a three dof translational manipulator and ii) the Agile eye; a parallel spherical wrist. First, the kinematic and dynamic models of the Orthoglide 5-axis are developed. The geometric and inertial parameters of the manipulator are determined by means of a CAD software. Then, the required motors performances are evaluated for some test trajectories. Finally, the motors are selected in the catalogue from the previous results.
Videobasierte Reflexion von Sprachförderkompetenzen im Unterricht. Eine vergleichende Analyse unterschiedlicher Stimulusformate
Creators: name: Hoge, Katharina
Publisher: name: TU Dortmund
Year: 2020
Subjects: subject: 360

description: Im Rahmen der vorliegenden Arbeit wurde untersucht, wie Lehramtsstudierende und Lehrkräfte über Sprachförderkompetenzen im Unterricht anhand der unterschiedlichen Stimulusformate Video (V) und Video + Transkript (VT) reflektieren. Im Fokus stand weiterhin, ob sich durch die Stimulusformate Unterschiede in den Reflexionen zeigen. Zur Zielgruppe gehörten Studierende des Bachelors und des Masters sonder- und inklusionspädagogischer Studiengänge sowie Lehrkräfte des Förderschwerpunkts Sprache. Die insgesamt 33 Proband*innen definierten im Rahmen einer Onlinebefragung zuerst den Begriff Reflexion. Anschließend reflektierten sie anhand zweier Unterrichtsvideos über die Sprachförderkompetenzen der dargestellten Lehrkräfte. Die Freitextantworten wurden mithilfe einer qualitativen Inhaltsanalyse ausgewertet. Zusätzlich beantworteten die Proband*innen Items unter anderem zum Thema kognitive Belastung, welche quantitativ ausgewertet wurden.
CFD-based prediction of initial microalgal adhesion to solid surfaces using force balances
Creators: name: Kichouh-Aiadi, S.
name: Sánchez-Mirón, A.
name: Gallardo-Rodríguez, J. J.
name: Soriano‐Jerez, Y.
name: Cerón-García, M. C.
name: García-Camacho, F.
name: Molina-Grima, E.
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Biophysics
subject: Space Science
subject: 29999 Physical Sciences not elsewhere classified
subject: FOS: Physical sciences
subject: Physiology
subject: FOS: Biological sciences
subject: Biotechnology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: 80699 Information Systems not elsewhere classified
subject: FOS: Computer and information sciences
subject: 19999 Mathematical Sciences not elsewhere classified
subject: FOS: Mathematics
subject: Cancer
subject: Computational Biology

description: Adhesion of microalgal cells to photobioreactor walls reduces productivity resulting in significant economic losses. The physico-chemical surface properties and the fluid dynamics present in the photobioreactor during cultivation are relevant. However, to date, no multiphysical model has been able to predict biofouling formation in these systems. In this work, to model the microalgal adhesion, a Computational Fluid Dynamic simulation was performed using a Eulerian-Lagrangian particle-tracking model. The adhesion criterion was based on the balance of forces and moments included in the XDLVO model. A cell suspension of the marine microalga Nannochloropsis gaditana was fed into a commercial flow cell composed of poly-methyl-methacrylate coupons for validation. Overall, the simulated adhesion criterion qualitatively predicted the initial distribution of adhered cells on the coupons. In conclusion, the combined Computational Fluid Dynamics-Discrete Phase Model (CFD-DPM) approach can be used to overcome the challenge of predicting microalgal cell adhesion in photobioreactors.
Antifouling properties of amphiphilic poly(3-hydroxyalkanoate): an environmentally-friendly coating
Creators: name: Guennec, A.
name: Brelle, L.
name: Balnois, E.
name: Linossier, I.
name: Renard, E.
name: Langlois, V.
name: Faÿ, F.
name: Chen, G. Q.
name: Simon-Colin, C.
name: Vallée-Réhel, K.
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Space Science
subject: Medicine
subject: Genetics
subject: FOS: Biological sciences
subject: Biotechnology
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Ecology
subject: Developmental Biology
subject: Inorganic Chemistry

description: The development of biofouling is a major problem for marine industries. The conception of antifouling and fouling release coatings, with controlled physical-chemical properties is a promising strategy. Among them, amphiphilic systems, such as those composed of a hydrophobic polydimethylsiloxane matrix and a hydrophilic polyethyleneglycol additive are the most efficient and up to date. Despite their effectiveness, these systems are questioned due to the petrochemical origin of PDMS. The aim of this project was to substitute the PDMS matrix with a biopolymer, poly(3-hydroxybuyrate-co-3-hydroxyvalerate) and to improve its anti-adhesion properties through the elaboration of an amphiphilic system, via the addition of PEG or PHBHHx-b-PEG copolymer. The results, including the physico-chemical properties of PHBHV based coatings and static adhesion tests on a marine bacterium, Bacillus 4J6 and a diatom, Phaeodactylum tricornutum are compared with those of PDMS and PEG-modified PDMS coatings. Real antiadhesion activity was obtained for the PHBHV/PHBHHx-b-PEG system for a promising eco-friendly strategy.
The Theory and Simulation of the 21-cm Background from the Epoch of Reionization
Creators: name: Shapiro, Paul R.
name: Iliev, Ilian T.
name: Mellema, Garrelt
name: Pen, Ue-Li
name: Merz, Hugh
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The redshifted 21-cm line of distant neutral H atoms provides a probe of the cosmic ``dark ages'' and the epoch of reionization (``EOR'') which ended them. The radio continuum produced by this redshifted line can be seen in absorption or emission against the CMB at meterwaves, yielding information about the thermal and ionization history of the universe and the primordial density perturbation spectrum that led to galaxy and large-scale structure formation. Observing this 21-cm background is a great challenge. A new generation of low-frequency radio arrays is currently under development to search for this background. Accurate theoretical predictions of the spectrum and anisotropy of this background, necessary to guide and interpret future observations, are also quite challenging. It is necessary to model the inhomogeneous reionization of the intergalactic medium and determine the spin temperature of the 21-cm transition and its variations in time and space as it decouples from the temperature of the CMB. Here, we focus on just a few of the predictions for the 21-cm background from the EOR, based on our newest, large-scale simulations of patchy reionization. These simulations are the first with enough N-body particles (from 5 to 29 billion) and radiative transfer rays to resolve the formation of and trace the ionizing radiation from each of the millions of dwarf galaxies believed responsible for reionization, down to 10^8 M_solar, in a cubic volume large enough (90 and 163 comoving Mpc on a side) to make meaningful statistical predictions of the fluctuating 21-cm background. (abridged)
description: Invited paper in The Evolution of Galaxies through the Neutral Hydrogen Window (AIP Conf. Proc.), eds. Minchin & Momjian, in press (2008). Accompanying movie at http://galileo.as.utexas.edu/reionization_sim_90Mpc_animated.mov
Anais do VI EPBIO: Encontro de Grupos PET de Biologia
Creators: name: PET Ciências Biológicas - UNIFESP Diadema
Publisher: name: Zenodo
Year: 2024
Subjects: biologia
extensão
universidade pública
PET
programa de educação tutorial
ensino
pesquisa
coleções biológicas

description: Os Anais do VI Encontro de Grupos PET de Biologia trazem em detalhes como foi a organização e realização do evento Encontro de Grupos PET de Biologia, realizado na Universidade Federal de São Paulo (UNIFESP), campus Diadema, do dia 7 de setembro de 2023 ao dia 9 de setembro de 2023, contando com a participação de integrantes de grupos PET de algumas universidades públicas do estado de São Paulo.
Singularity Analysis of Limited-dof Parallel Manipulators using Grassmann-Cayley Algebra
Creators: name: Kanaan, Daniel
name: Wenger, Philippe
name: Chablat, Damien
Publisher: name: arXiv
Year: 2008
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: This paper characterizes geometrically the singularities of limited DOF parallel manipulators. The geometric conditions associated with the dependency of six Plücker vector of lines (finite and infinite) constituting the rows of the inverse Jacobian matrix are formulated using Grassmann-Cayley algebra. Manipulators under consideration do not need to have a passive spherical joint somewhere in each leg. This study is illustrated with three example robots
Anti-biofouling efficacy of three home and personal care product preservatives: Pseudomonas aeruginosa biofilm inhibition and prevention
Creators: name: Curtin, A. M.
name: Thibodeau, M. C.
name: Buckley, H. L.
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Microbiology
subject: FOS: Biological sciences
subject: Biotechnology
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Ecology
subject: 69999 Biological Sciences not elsewhere classified
subject: 110309 Infectious Diseases
subject: FOS: Health sciences

description: Due to increasing water scarcity, it is essential to determine cost-effective and efficient methods of producing potable water, especially ones that utilize non-traditional sources. Although reverse osmosis (RO) shows promise as a key-player in mitigating water scarcity, it is limited by biofouling. It is therefore integral to identify effective antifoulants that also do not damage the membrane, cause resistance, or negatively impact human health and the environment. Potential antifoulants include preservatives used in home and personal care products. It is hypothesized that safer preservatives can be applied to RO systems to remove or prevent biofouling. Three preservatives including methylisothiazolinone (MIT), phenoxyethanol (PE), and sodium benzoate (SB) were tested via antimicrobial susceptibility tests against P. aeruginosa biofilms grown in 96-well plates to investigate both biofilm prevention and biofilm removal. Data were collected in the form of minimum biofilm inhibitory concentration (MBIC) and minimum biofilm eradication concentration (MBEC), respectively. MIT was the most effective of the three preservatives but also poses the highest hazard to human health and the environment. Due to efficacy and safety concerns, MIT, PE, and SB are not the final solution; however, a process was demonstrated for determining the efficacy of novel, safer antifoulants. Ultimately, further investigations into safer antifoulants, paired with a greater understanding of biofilm removal and prevention doses will help make RO a better solution for water scarcity.
Bose-Einstein condensation of relativistic Scalar Field Dark Matter
Creators: name: Ureña-López, L. Arturo
Publisher: name: arXiv
Year: 2008
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Standard thermodynamical results of ideal Bose gases are used to study the possible formation of a cosmological Bose-Einstein condensate in Scalar Field Dark Matter models; the main hypothesis is that the boson particles were in thermal equilibrium in the early Universe. It is then shown that the only relevant case needs the presence of both particles and anti-particles, and that it corresponds to models in which the bosonic particle is very light. Contrary to common wisdom, the condensate should be a relativistic phenomenon. Some cosmological implications are discussed in turn.
description: 5 RevTex pages, no figures, clarified discussion but conclusions unchanged
On the acceleration of Ultra-High-Energy Cosmic Rays
Creators: name: Fraschetti, Federico
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Ultra High Energy Cosmic Rays (UHECRs) hit the Earth's atmosphere with energies exceeding $10^{18}$ eV. This is the same energy as carried by a tennis ball moving at 100 km/h, but concentrated on a sub-atomic particle. UHECRs are so rare (the flux of particles with $E > 10^{20}$ eV is 0.5/km$^2$/century) that only a few such particles have been detected over the past 50 years. Recently, the HiRes and Auger experiments have reported the discovery of a high-energy cut-off in the UHECR spectrum, and Auger has found an apparent clustering of the highest energy events towards nearby active galactic nuclei. Consensus is building that the highest energy particles are accelerated within the radio-bright lobes of these objects, but it remains unclear how this actually happens, and whether the cut-off is due to propagation effects or reflects an intrinsically physical limitation of the acceleration process. The low event statistics presently allows for many different plausible models; nevertheless observations are beginning to impose strong constraints on them. These observations have also motivated suggestions that new physics may be implicated. We present a review of the key theoretical and observational issues related to the processes of propagation and acceleration of UHECRs and proposed solutions.
description: 11 pages, 3 figures. Invited review to appear in the Triennial edition of the Philosophical Transations of the Royal Society A. Final version accepted
Frege's ontology : a critical examination of its foundations
Creators: name: Rein, Andrew Paul
Publisher: name: University of British Columbia
Year: 2010

description: There are two contentious ontological claims that Frege makes. Firstly, that predicates have reference and secondly, that their reference is 'unsaturated'. It is the primary aim of this essay to examine the latter claim. Following an introductory exposition of the Fregean concepts crucial to this essay, the claim that the references of predicates are 'unsaturated' is considered as a response to the problem of the unity of the proposition. As a special case of this problem, F.H. Bradley's attack on relations is discussed. It is argued that once one understands that relations are unsaturated, Bradley's problem, and by extension the problem of the unity of the proposition, disappears. But a crucial semantic principle is shown to emerge from this attempted solution to these problems: Any language capable of talking about relations and concepts cannot refer to these by means of proper names. This principle, it then appears, renders us incapable of specifying in a given instance which concept a predicate refers to. Two recent attempts to avoid this problem are discussed and rejected. Insight gained from this discussion leads to a third, purely Fregean solution to the problem. This solution, which is forced upon Frege by his own principles, is seen to involve him in a vicious circle. It appears that Frege's ontological doctrines are ill-founded - that they cannot solve the very problems for which they were designed.
Electrical stress effect on Josephson tunneling through ultrathin AlOx barrier in Nb/Al/AlOx/Nb junctions
Creators: name: Tolpygo, Sergey K.
name: Amparo, Denis
Publisher: name: arXiv
Year: 2008
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The effect of dc electrical stress and breakdown on Josephson and quasiparticle tunneling in Nb/Al/AlOx/Nb junctions with ultrathin AlOx barriers typical for applications in superconductor digital electronics has been investigated. The junctions' conductance at room temperature and current-voltage (I-V) characteristics at 4.2 K have been measured after the consecutive stressing of the tunnel barrier at room temperature. Electrical stress was applied using current ramps with increasing amplitude ranging from 0 to ~1000 Ic corresponding to voltages across the barrier up to 0.65 V where Ic is the Josephson critical current. A very soft breakdown has been observed with polarity-dependent breakdown current (voltage). A dramatic increase in subgap conductance of the junctions, the appearance of subharmonic current steps, and gradual increase in both the critical and the excess currents as well as a decrease in the normal-state resistance have been observed. The observed changes in superconducting tunneling suggest a model in which a progressively increasing number of defects and associated additional conduction channels (superconducting quantum point contacts (SQPCs)) are induced by electric field in the tunnel barrier. By comparing the I-V characteristics of these conduction channels with the nonstationary theory of current transport in SQPCs based on multiple Andreev reflections by Averin and Bardas, the typical transparency D of the induced SQPCs was estimated as D ~ 0.7. The number of induced SQPCs was found to grow with voltage across the barrier as sinh(V/V_0) with V_0 = 0.045 V, in good agreement with the proposed model of defect formation by ion electromigration. The observed polarity dependence of the breakdown current (voltage) is also consistent with the model.
description: 11 pages, 10 figures
Dr. Top-k: Delegate-Centric Top-k on GPUs
Creators: name: Gaihre, Anil
name: Zheng, Da
name: Weitze, Scott
name: Li, Lingda
name: Song, Shuaiwen Leon
name: Ding, Caiwen
name: Li, Xiaoye S
name: Liu, Hang
Publisher: name: arXiv
Year: 2021
Subjects: subject: Information Retrieval (cs.IR)
subject: Databases (cs.DB)
subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: FOS: Computer and information sciences

description: Recent top-$k$ computation efforts explore the possibility of revising various sorting algorithms to answer top-$k$ queries on GPUs. These endeavors, unfortunately, perform significantly more work than needed. This paper introduces Dr. Top-k, a Delegate-centric top-$k$ system on GPUs that can reduce the top-$k$ workloads significantly. Particularly, it contains three major contributions: First, we introduce a comprehensive design of the delegate-centric concept, including maximum delegate, delegate-based filtering, and $β$ delegate mechanisms to help reduce the workload for top-$k$ up to more than 99%. Second, due to the difficulty and importance of deriving a proper subrange size, we perform a rigorous theoretical analysis, coupled with thorough experimental validations to identify the desirable subrange size. Third, we introduce four key system optimizations to enable fast multi-GPU top-$k$ computation. Taken together, this work constantly outperforms the state-of-the-art.
description: To be published in The International Conference for High Performance Computing, Networking, Storage and Analysis (SC 21)
The fractional nonlinear electrical lattice
Creators: name: Molina, Mario I.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Pattern Formation and Solitons (nlin.PS)
subject: FOS: Physical sciences

description: We examine the linear and nonlinear modes of a one-dimensional nonlinear electrical lattice, where the usual discrete Laplacian is replaced by a fractional discrete Laplacian. This induces a long-range intersite coupling that, at long distances, decreases as a power law. In the linear regime, we compute both, the spectrum of plane waves and the mean square displacement (MSD) of an initially localized excitation, in closed form in terms of regularized hypergeometric functions and the fractional exponent. The MSD shows ballistic behavior at long times, MSD$\sim t^2$ for all fractional exponents. When the fractional exponent is decreased from its standard integer value, the bandwidth decreases and the density of states shows a tendency towards degeneracy. In the limit of a vanishing exponent, the system becomes completely degenerate. For the nonlinear regime, we compute numerically the low-lying nonlinear modes, as a function of the fractional exponent. A modulational stability computation shows that, as the fractional exponent decreases, the number of electrical discrete solitons generated also decreases, eventually collapsing into a single soliton.
description: 6 pages, 6 figures
On a question of Erdos and Ulam
Creators: name: Solymosi, Jozsef
name: de Zeeuw, Frank
Publisher: name: arXiv
Year: 2008
Subjects: subject: Combinatorics (math.CO)
subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 52C10

description: Ulam asked in 1945 if there is an everywhere dense \emph{rational set}, i.e. a point set in the plane with all its pairwise distances rational. Erd\H os conjectured that if a set $S$ has a dense rational subset, then $S$ should be very special. The only known types of examples of sets with dense (or even just infinite) rational subsets are lines and circles. In this paper we prove Erd\H os's conjecture for algebraic curves, by showing that no irreducible algebraic curve other than a line or a circle contains an infinite rational set.
description: The previous version didn't cover one special case
CMB Beam Systematics: Impact on Lensing Parameter Estimation
Creators: name: Miller, N. J.
name: Shimon, M.
name: Keating, B. G.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The CMB's B-mode polarization provides a handle on several cosmological parameters most notably the tensor-to-scalar ratio, $r$, and is sensitive to parameters which govern the growth of large scale structure (LSS) and evolution of the gravitational potential. The primordial gravitational-wave- and secondary lensing-induced B-mode signals are very weak and therefore prone to various foregrounds and systematics. In this work we use Fisher-matrix-based estimations and apply, for the first time, Monte-Carlo Markov Chain (MCMC) simulations to determine the effect of beam systematics on the inferred cosmological parameters from five upcoming experiments: PLANCK, POLARBEAR, SPIDER, QUIET+CLOVER and CMBPOL. We consider beam systematics which couple the beam substructure to the gradient of temperature anisotropy and polarization (differential beamwidth, pointing and ellipticity) and beam systematics due to differential beam normalization (differential gain) and orientation (beam rotation) of the polarization-sensitive axes (the latter two effects are insensitive to the beam substructure). We determine allowable levels of beam systematics for given tolerances on the induced parameter errors and check for possible biases in the inferred parameters concomitant with potential increases in the statistical uncertainty. All our results are scaled to the 'worst case scenario'. In this case and for our tolerance levels, the beam rotation should not exceed the few-degree to sub-degree level, typical ellipticity is required to be 1% level, the differential gain allowed level is a few parts in $10^{3}$ to $10^{4}$, differential beamwidth upper limits are of the sub-percent level and differential pointing should not exceed the few- to sub-arcsec level.
description: 19 pages, 4 figures, 13 tables. Version matches published version
Metallicity in the Galactic Center: The Quintuplet cluster
Creators: name: Najarro, Francisco
name: Figer, Don F.
name: Hillier, D. John
name: Geballe, T. R.
name: Kudritzki, Rolf P.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present a measurement of metallicity in the Galactic center Quintuplet Cluster made using quantitative spectral analysis of two Luminous Blue Variables (LBVs). The analysis employs line-blanketed NLTE wind/atmosphere models fit to high-resolution near-infrared spectra containing lines of H, HeI, SiII, MgII, and FeII. We are able to break the H/He ratio vs. mass-loss rate degeneracy found in other LBVs and to obtain robust estimates of the He content of both objects. Our results indicate solar iron abundance and roughly twice solar abundance in the alpha-elements. These results are discussed within the framework of recent measurements of oxygen and carbon composition in the nearby Arches Cluster and iron abundances in red giants and supergiants within the central 30 pc of the Galaxy. The relatively large enrichment of alpha-elements with respect to iron is consistent with a history of more nucleosynthesis in high mass stars than the Galactic disk.
Solving the Homogeneous Boltzmann Equation with Arbitrary Scattering Kernel
Creators: name: Hohenegger, A.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: With applications in astroparticle physics in mind, we generalize a method for the solution of the nonlinear, space homogeneous Boltzmann equation with isotropic distribution function to arbitrary matrix elements. The method is based on the expansion of the matrix element in terms of two cosines of the "scattering angles". The scattering functions used by previous authors in particle physics for matrix elements in Fermi-approximation are retrieved as lowest order results in this expansion. The method is designed for the unified treatment of reactive mixtures of particles obeying different scattering laws, including the quantum statistical terms for blocking or stimulated emission, in possibly large networks of Boltzmann equations. Although our notation is the relativistic one, as it is used in astroparticle physics, the results can also be applied in the classical case.
description: 29 pages, 7 Postscript figures
Renormalization of chiral two-pion exchange NN interactions with Delta-excitations: Central Phases and the Deuteron
Creators: name: Valderrama, M. Pavon
name: Arriola, E. Ruiz
Publisher: name: arXiv
Year: 2008
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The renormalization of the chiral np interaction with Delta-excitations in intermediate states is considered at next-to-leading order (NLO) and next-to-next-to-leading order (N2LO) for central waves. The inclusion of the Delta-excitation as an explicit degree of freedom improves the convergence properties of the effective field theory results for np scattering with respect to Delta-less theory, and allows the existence of a deuteron bound state in the infinite cut-off limit. The 1S_0 singlet and 3S_1 triplet phase shifts reproduce data for p ~ m_pi. The role of spectral function regularization is also discussed.
description: 19 pages, 9 figures
Paeonol assists fluconazole and amphotericin B to inhibit virulence factors and pathogenicity of Candida albicans
Creators: name: Pan, Min
name: Wang, Qirui
name: Cheng, Ting
name: Wu, Daqiang
name: Wang, Tianming
name: Yan, Guiming
name: Shao, Jing
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Medicine
subject: Pharmacology
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Immunology
subject: FOS: Clinical medicine
subject: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences
subject: Cancer
subject: Computational Biology

description: This study aimed to evaluate the mono- and dual- antifungal activities of paeonol (PAE) and fluconazole (FLZ)/amphotericin B (AmB). To this end, the effects of PAE and FLZ/AmB on cell surface hydrophobicity, hydrolase activity, morphological transition were investigated in vitro and in a Galleria mellonella infection model. The results showed a relatively high minimum inhibitory concentration (MIC) and sessile MIC (SMIC) of PAE alone. However, compared with the single drug, the combined use of PAE and FLZ/AmB had a potent synergistic potential to inhibit the virulence factors for Candida. The concomitant use of two drugs was consistently more effective than either drug alone for increasing survival rate, decreasing the fungal burden, and alleviating the pathological features of G. mellonella infected by the fungus. Taken together, these findings demonstrate the anti-Candida effects of PAE plus FLZ/AmB and their potential to increase the sensitivity of C. albicans to FLZ/AmB of PAE.
On the stability of bubble functions and a stabilized mixed finite element formulation for the Stokes problem
Creators: name: Turner, D. Z.
name: Nakshatrala, K. B.
name: Hjelmstad, K. D.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics

description: In this paper we investigate the relationship between stabilized and enriched finite element formulations for the Stokes problem. We also present a new stabilized mixed formulation for which the stability parameter is derived purely by the method of weighted residuals. This new formulation allows equal order interpolation for the velocity and pressure fields. Finally, we show by counterexample that a direct equivalence between subgrid-based stabilized finite element methods and Galerkin methods enriched by bubble functions cannot be constructed for quadrilateral and hexahedral elements using standard bubble functions.
description: 25 pages, 13 figures (The previous version was compiled by mistake with the wrong style file, the current one uses amsart, and there is no difference in the text or the figures)