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- Discipline
- Keyword
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- Astrophysics - Earth and Planetary Astrophysics (3)
- X-rays: stars (3)
- Astrophysics - Solar and Stellar Astrophysics (2)
- Outflows (2)
- Planetary systems (2)
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- Stars: early-type (2)
- Stars: mass-loss (2)
- Stars: winds (2)
- Binaries: general (1)
- Carathéodory functions (1)
- Communication complexity (1)
- G-quadruplex (1)
- Hamming distance (1)
- Hydrodynamics (1)
- Information complexity (1)
- Instrumentation: adaptive optics (1)
- Line: profiles (1)
- MHD (1)
- Mitochondrial disease (1)
- Mitochondrial genome instability (1)
- MtDNA deletions (1)
- Non-B DNA (1)
- Nonlinear boundary conditions (1)
- Nonlinear parabolic systems (1)
- Nucleic acid structures (1)
- Planets and satellites: individual: HAT-P-32b (1)
- Protoplanetary disks (1)
- Quasimonotone properties (1)
- Shock waves (1)
- Stars: early-type; Stars: magnetic field (1)
- Publication
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Articles 1 - 29 of 29
Full-Text Articles in Physical Sciences and Mathematics
Association Of G-Quadruplex Forming Sequences With Human Mtdna Deletion Breakpoints, D. W. Dong, F. Pereira, Steven Paul Barrett , '13, J. E. Kolesar, K. Cao, J. Damas, Liliya A. Yatsunyk, F. B. Johnson, B. A. Kaufman
Association Of G-Quadruplex Forming Sequences With Human Mtdna Deletion Breakpoints, D. W. Dong, F. Pereira, Steven Paul Barrett , '13, J. E. Kolesar, K. Cao, J. Damas, Liliya A. Yatsunyk, F. B. Johnson, B. A. Kaufman
Chemistry & Biochemistry Faculty Works
Background: Mitochondrial DNA (mtDNA) deletions cause disease and accumulate during aging, yet our understanding of the molecular mechanisms underlying their formation remains rudimentary. Guanine-quadruplex (GQ) DNA structures are associated with nuclear DNA instability in cancer; recent evidence indicates they can also form in mitochondrial nucleic acids, suggesting that these non-B DNA structures could be associated with mtDNA deletions. Currently, the multiple types of GQ sequences and their association with human mtDNA stability are unknown. Results: Here, we show an association between human mtDNA deletion breakpoint locations (sites where DNA ends rejoin after deletion of a section) and sequences with G-quadruplex …
Measuring The Shock-Heating Rate In The Winds Of O Stars Using X-Ray Line Spectra, David H. Cohen, Zequn Li , '16, K. G. Gayley, S. P. Owocki, J. O. Sundqvist, V. Petit, M. A. Leutenegger
Measuring The Shock-Heating Rate In The Winds Of O Stars Using X-Ray Line Spectra, David H. Cohen, Zequn Li , '16, K. G. Gayley, S. P. Owocki, J. O. Sundqvist, V. Petit, M. A. Leutenegger
Physics & Astronomy Faculty Works
We present a new method for using measured X-ray emission line fluxes from O stars to determine the shock-heating rate due to instabilities in their radiation-driven winds. The high densities of these winds means that their embedded shocks quickly cool by local radiative emission, while cooling by expansion should be negligible. Ignoring for simplicity any non-radiative mixing or conductive cooling, the method presented here exploits the idea that the cooling post-shock plasma systematically passes through the temperature characteristic of distinct emission lines in the X-ray spectrum. In this way, the observed flux distribution among these X-ray lines can be used …
X-Ray Emission From Magnetic Massive Stars, Y. Nazé, V. Petit, M. Rinbrand, David H. Cohen, S. Owocki, A. Ud-Doula, G. A. Wade
X-Ray Emission From Magnetic Massive Stars, Y. Nazé, V. Petit, M. Rinbrand, David H. Cohen, S. Owocki, A. Ud-Doula, G. A. Wade
Physics & Astronomy Faculty Works
Magnetically confined winds of early-type stars are expected to be sources of bright and hard X-rays. To clarify the systematics of the observed X-ray properties, we have analyzed a large series of Chandra and XMM-Newton observations, corresponding to all available exposures of known massive magnetic stars (over 100 exposures covering ~60% of stars compiled in the catalog of Petit et al.). We show that the X-ray luminosity is strongly correlated with the stellar wind mass-loss rate, with a power-law form that is slightly steeper than linear for the majority of the less luminous, lower-${\dot{M}}$ B stars and flattens for the …
Configuration Spaces Of Convex And Embedded Polygons In The Plane, Don H. Shimamoto, Mary K. Wootters , '08
Configuration Spaces Of Convex And Embedded Polygons In The Plane, Don H. Shimamoto, Mary K. Wootters , '08
Mathematics & Statistics Faculty Works
This paper concerns the topology of configuration spaces of linkages whose underlying graph is a single cycle. Assume that the edge lengths are such that there are no configurations in which all the edges lie along a line. The main results are that, modulo translations and rotations, each component of the space of convex configurations is homeomorphic to a closed Euclidean ball and each component of the space of embedded configurations is homeomorphic to a Euclidean space. This represents an elaboration on the topological information that follows from the convexification theorem of Connelly, Demaine, and Rote.
N-Methylimidazole Promotes The Reaction Of Homophthalic Anhydride With Imines, J. Liu, Z. Wang, A. Levin, T. J. Emge, Paul R. Rablen, D. M. Floyd, S. Knapp
N-Methylimidazole Promotes The Reaction Of Homophthalic Anhydride With Imines, J. Liu, Z. Wang, A. Levin, T. J. Emge, Paul R. Rablen, D. M. Floyd, S. Knapp
Chemistry & Biochemistry Faculty Works
The addition of N-methylimidazole (NMI) to the reaction of homophthalic anhydride with imines such as pyridine-3-carboxaldehyde-N-trifluoroethylimine (9) reduces the amount of elimination byproduct and improves the yield of the formal cycloadduct, tetrahydroisoquinolonic carboxylate 10. Carboxanilides of such compounds are of interest as potential antimalarial agents. A mechanism that rationalizes the role of NMI is proposed, and a gram-scale procedure for the synthesis and resolution of 10 is also described.
Temporal And Spatial Turbulent Spectra Of Mhd Plasma And An Observation Of Variance Anisotropy, D. A. Schaffner, Michael R. Brown, Vyacheslav S. Lukin , '00
Temporal And Spatial Turbulent Spectra Of Mhd Plasma And An Observation Of Variance Anisotropy, D. A. Schaffner, Michael R. Brown, Vyacheslav S. Lukin , '00
Physics & Astronomy Faculty Works
The nature of magnetohydrodynamic (MHD) turbulence is analyzed through both temporal and spatial magnetic fluctuation spectra. A magnetically turbulent plasma is produced in the MHD wind tunnel configuration of the Swarthmore Spheromak Experiment. The power of magnetic fluctuations is projected into directions perpendicular and parallel to a local mean field; the ratio of these quantities shows the presence of variance anisotropy which varies as a function of frequency. Comparisons among magnetic, velocity, and density spectra are also made, demonstrating that the energy of the turbulence observed is primarily seeded by magnetic fields created during plasma production. Direct spatial spectra are …
X-Rays From Magnetically Confined Wind Shocks: Effect Of Cooling-Regulated Shock Retreat, A. Ud-Doula, S. Owocki, R. Townsend, V. Petit, David H. Cohen
X-Rays From Magnetically Confined Wind Shocks: Effect Of Cooling-Regulated Shock Retreat, A. Ud-Doula, S. Owocki, R. Townsend, V. Petit, David H. Cohen
Physics & Astronomy Faculty Works
We use 2D magnetohydrodynamic (MHD) simulations to examine the effects of radiative cooling and inverse Compton (IC) cooling on X-ray emission from magnetically confined wind shocks (MCWS) in magnetic massive stars with radiatively driven stellar winds. For the standard dependence of mass-loss rate on luminosity Ṁ∼ L1.7, the scaling of IC cooling with L and radiative cooling with Ṁ means that IC cooling become formally more important for lower luminosity stars. However, because the sense of the trends is similar, we find the overall effect of including IC cooling is quite modest. More significantly, for stars with high enough mass-loss …
Misaligned Protoplanetary Disks In A Young Binary Star System, Eric L.N. Jensen, R. L. Akeson
Misaligned Protoplanetary Disks In A Young Binary Star System, Eric L.N. Jensen, R. L. Akeson
Physics & Astronomy Faculty Works
Many extrasolar planets follow orbits that differ from the nearly coplanar and circular orbits found in our Solar System; their orbits may be eccentric or inclined with respect to the host star's equator, and the population of giant planets orbiting close to their host stars suggests appreciable orbital migration. There is at present no consensus on what produces such orbits. Theoretical explanations often invoke interactions with a binary companion star in an orbit that is inclined relative to the planet's orbital plane. Such mechanisms require significant mutual inclinations between the planetary and binary star orbital planes. The protoplanetary disks in …
Columnar Molecular Aggregation In The Aqueous Solutions Of Disodium Cromoglycate, D. M. Agra-Kooijman, G. Singh, A. Lorenz, Peter J. Collings, H.-S. Kitzerow, S. Kumar
Columnar Molecular Aggregation In The Aqueous Solutions Of Disodium Cromoglycate, D. M. Agra-Kooijman, G. Singh, A. Lorenz, Peter J. Collings, H.-S. Kitzerow, S. Kumar
Physics & Astronomy Faculty Works
Stack, chimneylike, and threadlike assemblies have previously been proposed for the structure of disodium cromoglycate (DSCG) aggregates in aqueous solutions. The results of the synchrotron x-ray scattering investigations reported here reveal the formation of simple columnar assemblies with pi-pi stacking at a separation of 3.4 angstrom between the DSCG molecules. Lateral separation between the assemblies is concentration and temperature dependent, varying from similar to 35 to 42 angstrom in the orientationally ordered nematic (N) phase and from 27 to 32 angstrom in the columnar or middle (M) phase having long range lateral positional order. The assemblies' length depends on concentration …
Transit Timing Analysis In The Hat-P-32 System, M. Seeliger, D. Dimitrov, D. Kjurkchieva, M. Mallonn, M. Fernandez, M. Kitze, V. Casanova, G. Maciejewski, J. M. Ohlert, J. G. Schmidt, A. Pannicke, D. Puchalski, W. Göğüş, T. Güver, S. Bilir, T. Ak, M. M. Hohle, T. O. B. Schmidt, R. Errmann, Eric L.N. Jensen, David H. Cohen, L. Marschall, G. Saral, I. Bernt, E. Derman, C. Gałan, R. Neuhäuser
Transit Timing Analysis In The Hat-P-32 System, M. Seeliger, D. Dimitrov, D. Kjurkchieva, M. Mallonn, M. Fernandez, M. Kitze, V. Casanova, G. Maciejewski, J. M. Ohlert, J. G. Schmidt, A. Pannicke, D. Puchalski, W. Göğüş, T. Güver, S. Bilir, T. Ak, M. M. Hohle, T. O. B. Schmidt, R. Errmann, Eric L.N. Jensen, David H. Cohen, L. Marschall, G. Saral, I. Bernt, E. Derman, C. Gałan, R. Neuhäuser
Physics & Astronomy Faculty Works
We present the results of 45 transit observations obtained for the transiting exoplanet HAT-P-32b. The transits have been observed using several telescopes mainly throughout the YETI (Young Exoplanet Transit Initiative) network. In 25 cases, complete transit light curves with a timing precision better than 1.4 min have been obtained. These light curves have been used to refine the system properties, namely inclination i, planet-to-star radius ratio Rp/Rs, and the ratio between the semimajor axis and the stellar radius a/Rs. First analyses by Hartman et al. suggests the existence of a second planet in the system, thus we tried to find …
Measurement Error In The Afqt In The Nlsy79, Lynne Steuerle Schofield
Measurement Error In The Afqt In The Nlsy79, Lynne Steuerle Schofield
Mathematics & Statistics Faculty Works
Many promising efforts in the social sciences aim to measure future outcomes (such as wages or health outcomes) given some base level of human capital or ability. They typically fail to recognize the proxies for human capital are all measured with error, creating bias in regression analysis. Here I show how item level data offers the opportunity to improve a broad range of economic, social and psychometric studies, an opportunity now enhanced significantly by the new release of item response level data for the Armed Forces Qualifying Test in the 1979 National Longitudinal Survey of Youth. (c) 2014 Elsevier B.V. …
Turbulence Analysis Of An Experimental Flux-Rope Plasma, D. A. Schaffner, Vyacheslav S. Lukin , '00, A. Wan, Michael R. Brown
Turbulence Analysis Of An Experimental Flux-Rope Plasma, D. A. Schaffner, Vyacheslav S. Lukin , '00, A. Wan, Michael R. Brown
Physics & Astronomy Faculty Works
We have previously generated elongated Taylor double-helix flux-rope plasmas in the SSX MHD wind tunnel. These plasmas are remarkable in their rapid relaxation (about one Alfven time) and their description by simple analytical Taylor force-free theory despite their high plasma beta and high internal flow speeds. We report on the turbulent features observed in these plasmas including frequency spectra, autocorrelation function, and probability distribution functions of increments. We discuss here the possibility that the turbulence facilitating access to the final state supports coherent structures and intermittency revealed by non-Gaussian signatures in the statistics. Comparisons to a Hall-MHD simulation of the …
Spontaneous Transfer Of Chirality In An Atropisomerically Enriched Two-Axis System, K. T. Barrett, A. J. Metrano, Paul R. Rablen, S. J. Miller
Spontaneous Transfer Of Chirality In An Atropisomerically Enriched Two-Axis System, K. T. Barrett, A. J. Metrano, Paul R. Rablen, S. J. Miller
Chemistry & Biochemistry Faculty Works
One of the most well-recognized stereogenic elements in a chiral molecule is an sp(3)-hybridized carbon atom that is connected to four different substituents. Axes of chirality can also exist about bonds with hindered barriers of rotation; molecules containing such axes are known as atropisomers(1). Understanding the dynamics of these systems can be useful, for example, in the design of single-atropisomer drugs(2) or molecular switches and motors(3). For molecules that exhibit a single axis of chirality, rotation about that axis leads to racemization as the system reaches equilibrium. Here we report a two-axis system for which an enantioselective reaction produces four …
Introductory Physics In Biological Context: An Approach To Improve Introductory Physics For Life Science Students, Catherine Hirshfeld Crouch, K. Heller
Introductory Physics In Biological Context: An Approach To Improve Introductory Physics For Life Science Students, Catherine Hirshfeld Crouch, K. Heller
Physics & Astronomy Faculty Works
We describe restructuring the introductory physics for life science students (IPLS) course to better support these students in using physics to understand their chosen fields. Our courses teach physics using biologically rich contexts. Specifically, we use examples in which fundamental physics contributes significantly to understanding a biological system to make explicit the value of physics to the life sciences. This requires selecting the course content to reflect the topics most relevant to biology while maintaining the fundamental disciplinary structure of physics. In addition to stressing the importance of the fundamental principles of physics, an important goal is developing students' quantitative …
Nexus/Physics: An Interdisciplinary Repurposing Of Physics For Biologists, E. F. Redish, C. Bauer, K. L. Carleton, T. J. Cooke, M. Cooper, Catherine Hirshfeld Crouch, B. W. Dreyfus, B. D. Geller, J. Giannini, J. S. Gouvea, M. W. Klymkowsky, W. Losert, K. Moore, J. Presson, V. Sawtelle, K. V. Thompson, C. Turpen, R. K.P. Zia
Nexus/Physics: An Interdisciplinary Repurposing Of Physics For Biologists, E. F. Redish, C. Bauer, K. L. Carleton, T. J. Cooke, M. Cooper, Catherine Hirshfeld Crouch, B. W. Dreyfus, B. D. Geller, J. Giannini, J. S. Gouvea, M. W. Klymkowsky, W. Losert, K. Moore, J. Presson, V. Sawtelle, K. V. Thompson, C. Turpen, R. K.P. Zia
Physics & Astronomy Faculty Works
In response to increasing calls for the reform of the undergraduate science curriculum for life science majors and pre-medical students (Bio2010, Scientific Foundations for Future Physicians, Vision & Change), an interdisciplinary team has created NEXUS/Physics: a repurposing of an introductory physics curriculum for the life sciences. The curriculum interacts strongly and supportively with introductory biology and chemistry courses taken by life-science students, with the goal of helping students build general, multi-discipline scientific competencies. NEXUS/Physics stresses interdisciplinary examples and the content differs markedly from traditional introductory physics to facilitate this: it extends the discussion of energy to include interatomic potentials and …
Observation Of Turbulent Intermittency Scaling With Magnetic Helicity In An Mhd Plasma Wind Tunnel, D. A. Schaffner, Adrian H. J. Wan , '15, Michael R. Brown
Observation Of Turbulent Intermittency Scaling With Magnetic Helicity In An Mhd Plasma Wind Tunnel, D. A. Schaffner, Adrian H. J. Wan , '15, Michael R. Brown
Physics & Astronomy Faculty Works
The intermittency in turbulent magnetic field fluctuations has been observed to scale with the amount of magnetic helicity injected into a laboratory plasma. An unstable spheromak injected into the MHD wind tunnel of the Swarthmore Spheromak Experiment displays turbulent magnetic and plasma fluctuations as it relaxes into a Taylor state. The level of intermittency of this turbulence is determined by finding the flatness of the probability distribution function of increments for magnetic pickup coil fluctuations B(t). The intermittency increases with the injected helicity, but spectral indices are unaffected by this variation. While evidence is provided which supports the hypothesis that …
N-Methylmesoporphyrin Ix Fluorescence As A Reporter Of Strand Orientation In Guanine Quadruplexes, Navin C. Sabharwal , '14, V. Savikhin, Joshua R. Turek-Herman , '16, John Michael Nicoludis , '12, V. A. Szalai, Liliya A. Yatsunyk
N-Methylmesoporphyrin Ix Fluorescence As A Reporter Of Strand Orientation In Guanine Quadruplexes, Navin C. Sabharwal , '14, V. Savikhin, Joshua R. Turek-Herman , '16, John Michael Nicoludis , '12, V. A. Szalai, Liliya A. Yatsunyk
Chemistry & Biochemistry Faculty Works
Guanine quadruplexes (GQ) are four-stranded DNA structures formed by guanine-rich DNA sequences. The formation of GQs inhibits cancer cell growth, although the detection of GQs invivo has proven difficult, in part because of their structural diversity. The development of GQ-selective fluorescent reporters would enhance our ability to quantify the number and location of GQs, ultimately advancing biological studies of quadruplex relevance and function. N-methylmesoporphyrin IX (NMM) interacts selectively with parallel-stranded GQs; in addition, its fluorescence is sensitive to the presence of DNA, making this ligand a possible candidate for a quadruplex probe. In the present study, we investigated the effect …
Thioflavin T As A Fluorescence Light-Up Probe For G4 Formation, A. R. De La Faverie, A. Guédin, A. Bedrat, Liliya A. Yatsunyk, J.-L. Mergny
Thioflavin T As A Fluorescence Light-Up Probe For G4 Formation, A. R. De La Faverie, A. Guédin, A. Bedrat, Liliya A. Yatsunyk, J.-L. Mergny
Chemistry & Biochemistry Faculty Works
Thioflavin T (ThT) becomes fluorescent in the presence of the G-quadruplex structure such as that formed by the human telomeric motif. In this report, we extend and generalize these observations and show that this dye may be used as a convenient and specific quadruplex probe. In the presence of most, but not all, G4-forming sequences, we observed a large increase in ThT fluorescence emission, whereas the presence of control duplexes and single strands had a more limited effect on emission. This differential behavior allowed us to design a high-throughput assay to detect G4 formation. Hundreds of different oligonucleotides may be …
Characterizing The Interactions Between Influenza A M2 Protein And Cholesterol In Membranes, Matthew R. Elkins , '14
Characterizing The Interactions Between Influenza A M2 Protein And Cholesterol In Membranes, Matthew R. Elkins , '14
Senior Theses, Projects, and Awards
The influenza A M2 protein is 97-residues in length and homotetramerizes to form a proton channel across the viral membrane early in the influenza life cycle. M2 is also implicated in the formation and budding of new viral particles in a process proposed to require membrane cholesterol. A potential cholesterol recognition amino acid consensus (CRAC) immediately C-terminal to the M2 transmembrane domain is thought to mediate the M2-cholesterol interaction. However, the finer details of this interaction are largely unknown. Using site-directed spin labeling (SDSL) and electron paramagnetic resonance (EPR) spectroscopy, this research aims to gain a more detailed understanding of …
Probing And Characterizing Different Conformations Of The Influenza A M2 Protein Using Sdsl-Epr Spectroscopy, Sangwoo Shawn Kim , '14
Probing And Characterizing Different Conformations Of The Influenza A M2 Protein Using Sdsl-Epr Spectroscopy, Sangwoo Shawn Kim , '14
Senior Theses, Projects, and Awards
The M2 protein is a 97-residue membrane homotetrameric protein found on the viral coat of the Influenza A virus. M2 plays a key role in virulence of the Influenza A virus. M2 was previously shown to act as a proton channel that can acidify a virion once it has entered the cell. Recently, M2 has also been implicated in generating curvature in the cell membrane to mediate budding of new viral progeny. Furthermore, the amino acid sequence of M2 contains a cholesterol recognition amino acid consensus (CRAC) domain, which indicates that M2 may interact with cholesterol. In this thesis, site-directed …
Sdsl-Epr Structural Studies Of The Cytoplasmic Helix In Novel Full-Length Constructs Of The Influenza A M2 Protein, Megan E. Thompson , '14
Sdsl-Epr Structural Studies Of The Cytoplasmic Helix In Novel Full-Length Constructs Of The Influenza A M2 Protein, Megan E. Thompson , '14
Senior Theses, Projects, and Awards
The M2 protein of the influenza A virus is a homotetrameric transmembrane proton channel implicated in several stages of the viral replication process. Each of its 97-residue monomers is known to include a transmembrane α-helix. but the structures of the N- and C-terminal domains have not yet been solved. A significant barrier to an atomic level understanding of the M2 protein is the difficulty associated with expression and purification of the full-length protein, which has primarily been studied in the form of truncated constructs covering the amphipathic helix and a short C-terminal segment. This C-terminal segment, which includes residues 46-62, …
Investigation Of Porphyrins As Potential G-Quadruplex Stabilizing Ligands And Fluorescent Probes, Navin C. Sabharwal , '14
Investigation Of Porphyrins As Potential G-Quadruplex Stabilizing Ligands And Fluorescent Probes, Navin C. Sabharwal , '14
Senior Theses, Projects, and Awards
G-quadruplex (GQ) DNA is a non-canonical DNA structure thought to form throughout the human genome. Because the stabilization of quadruplexes formed in the telomeres and in the promoters of oncogenes may prevent the spread of cancer cells, there is great interest in developing and studying molecules that may bind to and stabilize these unique DNA structures. This thesis investigates the interactions between porphyrins and GQ DNA with the goal of determining how strongly and selectively porphyrins can stabilize the quadruplex structure. There is also great interest in developing luminescent probes for GQ structures to allow for their detection in vivo. …
Measuring Mass-Loss Rates And Constraining Shock Physics Using X-Ray Line Profiles Of O Stars From The Chandra Archive, David H. Cohen, Emma E. Wollman , '09, M. A. Leutenegger, J. O. Sundqvist, A. W. Fullerton, J. Zsargó, S. P. Owocki
Measuring Mass-Loss Rates And Constraining Shock Physics Using X-Ray Line Profiles Of O Stars From The Chandra Archive, David H. Cohen, Emma E. Wollman , '09, M. A. Leutenegger, J. O. Sundqvist, A. W. Fullerton, J. Zsargó, S. P. Owocki
Physics & Astronomy Faculty Works
We quantitatively investigate the extent of wind absorption signatures in the X-ray grating spectra of all non-magnetic, effectively single O stars in the Chandra archive via line profile fitting. Under the usual assumption of a spherically symmetric wind with embedded shocks, we confirm previous claims that some objects show little or no wind absorption. However, many other objects do show asymmetric and blueshifted line profiles, indicative of wind absorption. For these stars, we are able to derive wind mass-loss rates from the ensemble of line profiles, and find values lower by an average factor of 3 than those predicted by …
Equivariant Quantum Schubert Polynomials, D. Anderson, Linda Chen
Equivariant Quantum Schubert Polynomials, D. Anderson, Linda Chen
Mathematics & Statistics Faculty Works
We establish an equivariant quantum Giambelli formula for partial flag varieties. The answer is given in terms of a specialization of universal double Schubert polynomials. Along the way, we give new proofs of the presentation of the equivariant quantum cohomology ring, as well as Graham-positivity of the structure constants in equivariant quantum Schubert calculus. (C) 2013 Elsevier Inc. All rights reserved.
Elasticity-Dependent Self-Assembly Of Micro-Templated Chromonic Liquid Crystal Films, M. A. Lohr, M. Cavallaro Jr., D. A. Beller, K. J. Stebe, R. D. Kamien, Peter J. Collings, A. G. Yodh
Elasticity-Dependent Self-Assembly Of Micro-Templated Chromonic Liquid Crystal Films, M. A. Lohr, M. Cavallaro Jr., D. A. Beller, K. J. Stebe, R. D. Kamien, Peter J. Collings, A. G. Yodh
Physics & Astronomy Faculty Works
We explore micropatterned director structures of aqueous lyotropic chromonic liquid crystal (LCLC) films created on square-lattice cylindrical-micropost substrates. The structures are manipulated by modulating the LCLC mesophases and their elastic properties via concentration through drying. Nematic LCLC films exhibit preferred bistable alignment along the diagonals of the micropost lattice. Columnar LCLC films, dried from nematics, form two distinct director and defect configurations: a diagonally aligned director pattern with local squares of defects, and an off-diagonal configuration with zig-zag defects. The formation of these states appears to be tied to the relative splay and bend free energy costs of the initial …
Circumstellar Disks Around Binary Stars In Taurus, R. L. Akeson, Eric L.N. Jensen
Circumstellar Disks Around Binary Stars In Taurus, R. L. Akeson, Eric L.N. Jensen
Physics & Astronomy Faculty Works
We have conducted a survey of 17 wide (〉100 AU) young binary systems in Taurus with the Atacama Large Millimeter Array (ALMA) at two wavelengths. The observations were designed to measure the masses of circumstellar disks in these systems as an aid to understanding the role of multiplicity in star and planet formation. The ALMA observations had sufficient resolution to localize emission within the binary system. Disk emission was detected around all primaries and 10 secondaries, with disk masses as low as 10-4 M ☉. We compare the properties of our sample to the population of known disks …
Kelt-6b: A P ~ 7.9 Day Hot Saturn Transiting A Metal-Poor Star With A Long-Period Companion, K. A. Collins, J. D. Eastman, T. G. Beatty, R. J. Siverd, B. S. Gaudi, J. Pepper, J. F. Kielkopf, J. A. Johnson, A. W. Howard, D. A. Fischer, M. Manner, A. Bieryla, D. W. Latham, B. J. Fulton, J. Gregorio, L. A. Buchhave, Eric L.N. Jensen, K. G. Stassun, K. Penev, J. R. Crepp, S. Hinkley, R. A. Street, P. Cargile, C. E. Mack, T. E. Oberst, R. L. Avril, S. N. Mellon, K. K. Mcleod, M. T. Penny, R. P. Stefanik, P. Berlind, M. L. Calkins, Q. Mao, A. J.W. Richert, D. L. Depoy, G. A. Esquerdo, A. Gould, J. L. Marshall, R. J. Oelkers, R. W. Pogge, M. Trueblood, P. Trueblood
Kelt-6b: A P ~ 7.9 Day Hot Saturn Transiting A Metal-Poor Star With A Long-Period Companion, K. A. Collins, J. D. Eastman, T. G. Beatty, R. J. Siverd, B. S. Gaudi, J. Pepper, J. F. Kielkopf, J. A. Johnson, A. W. Howard, D. A. Fischer, M. Manner, A. Bieryla, D. W. Latham, B. J. Fulton, J. Gregorio, L. A. Buchhave, Eric L.N. Jensen, K. G. Stassun, K. Penev, J. R. Crepp, S. Hinkley, R. A. Street, P. Cargile, C. E. Mack, T. E. Oberst, R. L. Avril, S. N. Mellon, K. K. Mcleod, M. T. Penny, R. P. Stefanik, P. Berlind, M. L. Calkins, Q. Mao, A. J.W. Richert, D. L. Depoy, G. A. Esquerdo, A. Gould, J. L. Marshall, R. J. Oelkers, R. W. Pogge, M. Trueblood, P. Trueblood
Physics & Astronomy Faculty Works
We report the discovery of KELT-6b, a mildly inflated Saturn-mass planet transiting a metal-poor host. The initial transit signal was identified in KELT-North survey data, and the planetary nature of the occulter was established using a combination of follow-up photometry, high-resolution imaging, high-resolution spectroscopy, and precise radial velocity measurements. The fiducial model from a global analysis including constraints from isochrones indicates that the V = 10.38 host star (BD+31 2447) is a mildly evolved, late-F star with T eff = 6102 ± 43 K, log g_\star =4.07_{-0.07}^{+0.04}, and [Fe/H] = -0.28 ± 0.04, with an inferred mass M sstarf = …
The Information Complexity Of Hamming Distance, E. Blais, Joshua Brody, B. Ghazi
The Information Complexity Of Hamming Distance, E. Blais, Joshua Brody, B. Ghazi
Computer Science Faculty Works
The Hamming distance function Ham_{n,d} returns 1 on all pairs of inputs x and y that differ in at most d coordinates and returns 0 otherwise. We initiate the study of the information complexity of the Hamming distance function. We give a new optimal lower bound for the information complexity of the Ham_{n,d} function in the small-error regime where the protocol is required to err with probability at most epsilon < d/n. We also give a new conditional lower bound for the information complexity of Ham_{n,d} that is optimal in all regimes. These results imply the first new lower bounds on the communication complexity of the Hamming distance function for the shared randomness two-way communication model since Pang and El-Gamal (1986). These results also imply new lower bounds in the areas of property testing and parity decision tree complexity.
Strong Bounded Solutions For Nonlinear Parabolic Systems, Nsoki Mavinga, M. N. Nkashama
Strong Bounded Solutions For Nonlinear Parabolic Systems, Nsoki Mavinga, M. N. Nkashama
Mathematics & Statistics Faculty Works
In this article we study the existence of strong bounded solutions for nonlinear parabolic systems on a domain which is bounded in space and unbounded in time (namely the entire real line). We use nonlinear iteration arguments combined with some a priori estimates to derive the existence results. We also provide conditions under which we have a positive solution. Some examples are given to illustrate the results.