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Full-Text Articles in Physical Sciences and Mathematics
Oga Inhibition By Glcnac-Selenazoline, E. J. Kim, D. C. Love, E. Darout, M. Abdo, B. Rempel, S. G. Withers, Paul R. Rablen, J. A. Hanover, S. Knapp
Oga Inhibition By Glcnac-Selenazoline, E. J. Kim, D. C. Love, E. Darout, M. Abdo, B. Rempel, S. G. Withers, Paul R. Rablen, J. A. Hanover, S. Knapp
Chemistry & Biochemistry Faculty Works
The title compound, which differs from the powerful O-GlcNAcase (OGA) inhibitor GlcNAc-thiazoline only at the chalcogen atom (Se for S), is a much weaker inhibitor in a direct OGA assay. In human cells, however, the selenazoline shows comparable ability to induce hyper-O-GlcNAc-ylation, and the two show similar reduction of insulin-stimulated translocation of glucose transporter 4 in differentiated 3T3 adipocytes. (C) 2010 Elsevier Ltd. All rights reserved.
A Multiphase Suzaku Study Of X-Rays From Τ Sco, R. Ignace, L. M. Oskinova, M. Jardine, J. P. Cassinelli, David H. Cohen, J.-F. Donati, R. H.D. Townsend, A. Ud-Doula
A Multiphase Suzaku Study Of X-Rays From Τ Sco, R. Ignace, L. M. Oskinova, M. Jardine, J. P. Cassinelli, David H. Cohen, J.-F. Donati, R. H.D. Townsend, A. Ud-Doula
Physics & Astronomy Faculty Works
We obtained relatively high signal-to-noise X-ray spectral data of the early massive star tau Sco (B0.2V) with the Suzaku X-ray Imaging Spectrometer (XIS) instrument. This source displays several unusual features that motivated our study: (1) redshifted absorption in UV P Cygni lines to approximately +250 km s(-1) suggestive of infalling gas, (2) unusually hard X-ray emission requiring hot plasma at temperatures in excess of 10 MK whereas most massive stars show relatively soft X-rays at a few MK, and (3) a complex photospheric magnetic field of open and closed field lines. In an attempt to understand the hard component better, …
Three-Dimensional Reconnection And Relaxation Of Merging Spheromak Plasmas, Timothy G. Gray , '01, Vyacheslav S. Lukin , '00, Michael R. Brown, C. D. Cothran
Three-Dimensional Reconnection And Relaxation Of Merging Spheromak Plasmas, Timothy G. Gray , '01, Vyacheslav S. Lukin , '00, Michael R. Brown, C. D. Cothran
Physics & Astronomy Faculty Works
Plasma relaxation inside a highly conducting cylindrical boundary is studied both experimentally and computationally. Dynamics are initiated by the introduction of two equal helicity spheromaks at either end of the cylinder. In the experiment, dense, high-magnetic-flux spheromaks are injected into the flux conserving volume with magnetized plasma guns. In the simulation, identical spheromaks initially occupy both halves of the cylinder and a perturbation is introduced. Merging commences with a single three-dimensional null-point that moves radially out of the flux conserving volume at velocities up to 0.2 of the reconnection outflow velocity. Relaxation to the minimum energy state occurs in about …
Review Of "The Science On Women And Science" Edited By C. H. Sommers, Amy Lisa Graves
Review Of "The Science On Women And Science" Edited By C. H. Sommers, Amy Lisa Graves
Physics & Astronomy Faculty Works
No abstract provided.
Macroevolutionary Patterns In The Evolutionary Radiation Of Archosaurs (Tetrapoda: Diapsida), S. L. Brusatte, M. J. Benton, G. T. Lloyd, M. Ruta, Steve C. Wang
Macroevolutionary Patterns In The Evolutionary Radiation Of Archosaurs (Tetrapoda: Diapsida), S. L. Brusatte, M. J. Benton, G. T. Lloyd, M. Ruta, Steve C. Wang
Mathematics & Statistics Faculty Works
The rise of archosaurs during the Triassic and Early Jurassic has been treated as a classic example of an evolutionary radiation in the fossil record. This paper reviews published studies and provides new data on archosaur lineage origination, diversity and lineage evolution, morphological disparity, rates of morphological character change, and faunal abundance during the Triassic–Early Jurassic. The fundamental archosaur lineages originated early in the Triassic, in concert with the highest rates of character change. Disparity and diversity peaked later, during the Norian, but the most significant increase in disparity occurred before maximum diversity. Archosaurs were rare components of Early–Middle Triassic …
Modeling Broadband X-Ray Absorption Of Massive Star Winds, M. A. Leutenegger, David H. Cohen, J. Zsargó, Erin Marie Martell , '09, James Paton Macarthur , '11, S. P. Owocki, M. Gagné, D. J. Hillier
Modeling Broadband X-Ray Absorption Of Massive Star Winds, M. A. Leutenegger, David H. Cohen, J. Zsargó, Erin Marie Martell , '09, James Paton Macarthur , '11, S. P. Owocki, M. Gagné, D. J. Hillier
Physics & Astronomy Faculty Works
We present a method for computing the net transmission of X-rays emitted by shock-heated plasma distributed throughout a partially optically thick stellar wind from a massive star. We find the transmission by an exact integration of the formal solution, assuming that the emitting plasma and absorbing plasma are mixed at a constant mass ratio above some minimum radius, below which there is assumed to be no emission. This model is more realistic than either the slab absorption associated with a corona at the base of the wind or the exospheric approximation that assumes that all observed X-rays are emitted without …
A Mass-Loss Rate Determination For Zeta Puppis From The Quantitative Analysis Of X-Ray Emission-Line Profiles, David H. Cohen, M. A. Leutenegger, Emma Edwina Wollman , '09, J. Zsargó, D. J. Hillier, R. H.D. Townsend, S. P. Owocki
A Mass-Loss Rate Determination For Zeta Puppis From The Quantitative Analysis Of X-Ray Emission-Line Profiles, David H. Cohen, M. A. Leutenegger, Emma Edwina Wollman , '09, J. Zsargó, D. J. Hillier, R. H.D. Townsend, S. P. Owocki
Physics & Astronomy Faculty Works
We fit every emission line in the high-resolution Chandra grating spectrum of. Pup with an empirical line profile model that accounts for the effects of Doppler broadening and attenuation by the bulk wind. For each of 16 lines or line complexes that can be reliably measured, we determine a best-fitting fiducial optical depth, tau(*) equivalent to kappa(M) over dot/4 pi R(*)upsilon(infinity), and place confidence limits on this parameter. These 16 lines include seven that have not previously been reported on in the literature. The extended wavelength range of these lines allows us to infer, for the first time, a clear …
Exploiting Laboratory And Heliophysics Plasma Synergies, J. Dahlburg, W. Amatucci, Michael R. Brown, V. Chan, J. Chen, C. D. Cothran, D. Chua, R. Dahlburg, G. Doschek, J. Egedal, F. Cary, R. Howard, J. Huba, Y.-K. Ko, J. Krall, J. M. Laming, R. Lin, M. Linton, Vyacheslav S. Lukin , '00, R. Murphy, C. Rakowski, D. Socker, A. Tylka, A. Vourlidas, H. Warren, B. Wood
Exploiting Laboratory And Heliophysics Plasma Synergies, J. Dahlburg, W. Amatucci, Michael R. Brown, V. Chan, J. Chen, C. D. Cothran, D. Chua, R. Dahlburg, G. Doschek, J. Egedal, F. Cary, R. Howard, J. Huba, Y.-K. Ko, J. Krall, J. M. Laming, R. Lin, M. Linton, Vyacheslav S. Lukin , '00, R. Murphy, C. Rakowski, D. Socker, A. Tylka, A. Vourlidas, H. Warren, B. Wood
Physics & Astronomy Faculty Works
Recent advances in space-based heliospheric observations, laboratory experimentation, and plasma simulation codes are creating an exciting new cross-disciplinary opportunity for understanding fast energy release and transport mechanisms in heliophysics and laboratory plasma dynamics, which had not been previously accessible. This article provides an overview of some new observational, experimental, and computational assets, and discusses current and near-term activities towards exploitation of synergies involving those assets. This overview does not claim to be comprehensive, but instead covers mainly activities closely associated with the authors' interests and reearch. Heliospheric observations reviewed include the Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) on …
Discovery Of Rotational Braking In The Magnetic Helium-Strong Star Sigma Orionis E, R. H.D. Townsend, M. E. Oksala, David H. Cohen, S. P. Owocki, A. Ud-Doula
Discovery Of Rotational Braking In The Magnetic Helium-Strong Star Sigma Orionis E, R. H.D. Townsend, M. E. Oksala, David H. Cohen, S. P. Owocki, A. Ud-Doula
Physics & Astronomy Faculty Works
We present new U-band photometry of the magnetic helium-strong star sigma Ori E, obtained over 2004-2009 using the SMARTS 0.9 m telescope at Cerro Tololo Inter-American Observatory. When combined with historical measurements, these data constrain the evolution of the star's 1.19 day rotation period over the past three decades. We are able to rule out a constant period at the p(null) = 0.05% level, and instead find that the data are well described (p(null) = 99.3%) by a period increasing linearly at a rate of 77 ms per year. This corresponds to a characteristic spin-down time of 1.34 Myr, in …
Observation Of A Nonaxisymmetric Magnetohydrodynamic Self-Organized State, C. D. Cothran, Michael R. Brown, T. Gray, M. J. Schaffer, G. Marklin, Vyacheslav S. Lukin , '00
Observation Of A Nonaxisymmetric Magnetohydrodynamic Self-Organized State, C. D. Cothran, Michael R. Brown, T. Gray, M. J. Schaffer, G. Marklin, Vyacheslav S. Lukin , '00
Physics & Astronomy Faculty Works
A nonaxisymmetric stable magnetohydrodynamic(MHD) equilibrium within a prolate cylindrical conducting boundary has been produced experimentally at Swarthmore Spheromak Experiment (SSX) [M. R. Brown et al., Phys. Plasmas6, 1717 (1999)]. It has m=1toroidal symmetry, helical distortion, and flat λ profile. Each of these observed characteristics are in agreement with the magnetically relaxed minimum magnetic energy Taylor state. The Taylor state is computed using the methods described by A. Bondeson et al. [Phys. Fluids24, 1682 (1981)] and by J. M. Finn et al. [Phys. Fluids24, 1336 (1981)] and is compared in detail to the measured internal magnetic structure. The lifetime of this …
A Test Of Pre-Main-Sequence Lithium Depletion Models, Jennifer Chun Ming Yee , '07, Eric L.N. Jensen
A Test Of Pre-Main-Sequence Lithium Depletion Models, Jennifer Chun Ming Yee , '07, Eric L.N. Jensen
Physics & Astronomy Faculty Works
Despite the extensive study of lithium depletion during pre-main-sequence (PMS) contraction, studies of individual stars show discrepancies between ages determined from the Hertzsprung-Russell (H-R) diagram and ages determined from lithium depletion, indicating open questions in the PMS evolutionary models. To further test these models, we present high-resolution spectra for members of the beta Pictoris Moving Group (BPMG), which is young and nearby. We measure equivalent widths of the 6707.8 angstrom Li I line in these stars and use them to determine lithium abundances. We combine the lithium abundance with the predictions of PMS evolutionary models in order to calculate a …
Stable Spheromak Formation By Merging In An Oblate Flux Conserver, Timothy G. Gray , '01, Michael R. Brown, C. D. Cothran, G. Marklin, M. J. Schaffer
Stable Spheromak Formation By Merging In An Oblate Flux Conserver, Timothy G. Gray , '01, Michael R. Brown, C. D. Cothran, G. Marklin, M. J. Schaffer
Physics & Astronomy Faculty Works
An axisymmetric spheromak formed by the dynamic merging of two smaller spheromaks of the same magnetic helicity in the Swarthmore Spheromak Experiment (SSX) [M. R. Brown, Phys. Plasmas 6, 1717 (1999)] has been observed and characterized. The spheromak is formed in an oblate (tilt stable), trapezoidal, 6 mm wall copper flux conserver in SSX, which is 0.5 m in diameter and L=0.4 m in length at its largest dimensions. This configuration is formed by cohelicity merging of two spheromaks (either both right-handed or both left-handed) in which the merging poloidal fluxes are parallel (i.e., no field reversal for reconnection to …
Conformations Of A Model Protein Revealed By An Aggregating Cuᴵᴵ Porphyrin: Sensing The Difference, G. De Luca, A. Romeo, L. M. Scolaro, Robert F. Pasternack
Conformations Of A Model Protein Revealed By An Aggregating Cuᴵᴵ Porphyrin: Sensing The Difference, G. De Luca, A. Romeo, L. M. Scolaro, Robert F. Pasternack
Chemistry & Biochemistry Faculty Works
Aggregated t-CuP binds to poly-L-glutamate through supramolecular interactions, revealing itself to be an extremely sensitive probe for the major conformations of the polymeric scaffold.
Computer Science And The Liberal Arts: A Philosophical Examination, H. M. Walker, Charles F. Kelemen
Computer Science And The Liberal Arts: A Philosophical Examination, H. M. Walker, Charles F. Kelemen
Computer Science Faculty Works
This article explores the philosophy and position of the discipline of computer science within the liberal arts, based upon a discussion of the nature of computer science and a review of the characteristics of the liberal arts. A liberal arts environment provides important opportunities for undergraduate programs, but also presents important constraints. A well designed program can flourish in this environment, and evidence indicates that a liberal arts program in computer science can indeed succeed well.
Packing Rates Of Measures And A Conjecture For The Packing Density Of 2413, C. B. Presutti, Walter Stromquist
Packing Rates Of Measures And A Conjecture For The Packing Density Of 2413, C. B. Presutti, Walter Stromquist
Mathematics & Statistics Faculty Works
We give a new lower bound of 0.10472422757673209041 for the packing density of 2413, justify it by a construction, and conjecture that this value is actually equal to the packing density. Along the way we define the packing rate of a permutation with respect to a measure, and show that maximizing the packing rate of a pattern over all measures gives the packing density of the pattern.