Now showing items 932-951 of 965

  • van der Waals and hygroscopic forces of adhesion generated by spider capture threads 

    Hawthorn, A. C.; Opell, B. D. (Company of Biologists Ltd., 2003-11)
    Cribellar thread is the most primitive type of sticky prey capture thread found in aerial spider webs. Its outer surface is formed of thousands of fine fibrils that issue from a cribellum spinning field. The fibrils of ...
  • variation in ecosystem function in Appalachian streams along an acidity gradient 

    Simon, K. S.; Simon, M. A.; Benfield, E. F. (Ecological Society of America, 2009-07)
    Acidification is a widespread phenomenon that damages aquatic systems, and it has been the focus of intensive management efforts. While most management has focused on community structure as an endpoint, ecosystem function ...
  • Variation in Testosterone and Corticosterone in Amphibians and Reptiles: Relationships with Latitude, Elevation, and Breeding Season Length 

    Eikenaar, C.; Husak, J.; Escallon, C.; Moore, I. T. (University of Chicago Press, 2012-11)
    Latitudinal variation in life-history traits has been the focus of numerous investigations, but underlying hormonal mechanisms have received much less attention. Steroid hormones play a central role in vertebrate reproduction ...
  • Variational and nonvariational principles in quantum transport calculations 

    Yang, Z. Q.; Tackett, A.; Di Ventra, M. (American Physical Society, 2002-07)
    A variational principle is not generally satisfied in steady-state quantum transport as opposed to the case of ground-state problems. We show that for a short-range potential, a functional for the scattering amplitude can ...
  • Variational ground state for the periodic Anderson model 

    Bowen, Samuel P.; Mancini, Jay D. (American Institute of Physics, 1988-04-15)
    A variational calculation of the ground state of the Anderson lattice model is discussed. The calculation creates a finite Hamiltonian matrix for many_electron states, which are appropriate for the thermodynamic limit. A ...
  • Variational study of the spin-gap phase of the one-dimensional t-J model 

    Chen, Y. C.; Lee, T. K. (American Physical Society, 1996-10-01)
    We propose a correlated spin-singlet-pair wave function to describe the spin-gap phase of the one-dimensional t-J model at low density and large J/t. In addition to having singlet pairs, this wave function has a Jastrow ...
  • Viability of competing field theories for the driven lattice gas 

    Schmittmann, B.; Janssen, H. K.; Tauber, U. C.; Zia, R. K. P.; Leung, K. T.; Cardy, J. L. (American Physical Society, 2000-05)
    It has recently been suggested that the driven lattice gas should be described by an alternate held theory in the limit of infinite drive. We review the original and the alternate field theory, invoking several well-documented ...
  • Vibrational spectrum of the endohedral Y2C2@C-92 fullerene by Raman spectroscopy: Evidence for tunneling of the diatomic C-2 molecule 

    Burke, B. G.; Chan, J.; Williams, K. A.; Fuhrer, T.; Fu, W. J.; Dorn, H. C.; Puretzky, A. A.; Geohegan, D. B. (American Physical Society, 2011-03)
    The structure and vibrational spectrum of the novel endohedral fullerene Y2C2@C-92 was studied by Raman spectroscopy, with particular emphasis on the rotational transitions of the diatomic C-2 unit in the low-energy Raman ...
  • viscosity and density stratification in vertical Poiseuille flow 

    Renardy, Y. (AIP Publishing, 1987-06)
    The linear stability of plane three_layer vertical Poiseuille flow is considered. The layers are composed of two immiscible fluids, one next to the walls and one centrally located. The fluids have different viscosities and ...
  • Vlasov theory of plasma oscillations: linear-approximation 

    Arthur, M. D.; Greenberg, W.; Zweifel, P. F. (AIP Publishing, 1977)
    A functional analytic approach to the linearized collisionless Vlasov equation is presented utilizing a resolvent integration technique on the resolvent of the transport operator evaluated at a particular point. Formulae ...
  • volume holograms constructed from computer-generated masks 

    Case, S. K.; Dallas, W. J. (Optical Society of America, 1978-05)
    A new type of hologram that combines computer-generated holograms with volume holograms is described. This hologram allows arbitrary selection of the location and color of a computer-generated image when white light ...
  • Voluntary Income Tax, Voluntary Speed Limits 

    Cairns, John (Virginia Tech, 2014-01-22)
    The US administration insists that any plan to reduce greenhouse gas emissions be voluntary and devised by individual countries rather than a worldwide agreement or treaty. Other countries, especially European countries, ...
  • wall energy relaxation in the Cahn-Hilliard model for moving contact lines 

    Yue, P. T.; Feng, J. J. (AIP Publishing, 2011-01)
    The Cahn-Hilliard model uses diffusion between fluid components to regularize the stress singularity at a moving contact line. In addition, it represents the dynamics of the near-wall layer by the relaxation of a wall ...
  • water relations of the eggs of anolis-auratus and anolis-limifrons 

    Andrews, R. M.; Sexton, O. J. (Ecological Society of America, 1981)
    Eggs of Anolis auratus and Anolis limifrons were incubated on soil substrates differing in matric potential of soil water. Eggs of both species hatched after a mean incubation time of 44 d on soils with matric potentials ...
  • Water-Dispersible Cationic Polyurethanes Containing Pendant Trialkylphosphoniums 

    Zhang, Musan; Hemp, Sean T.; Zhang, Mingqiang; Allen, Michael H., Jr.; Carmean, Richard N.; Moore, Robert B.; Long, Timothy E. (The Royal Society of Chemistry, 2014-03-06)
    Novel trialkylphosphonium ionic liquids chain extenders enabled the successful synthesis of poly(ethylene glycol)-based, cationic polyurethanes with pendant phosphoniums in the hard segments (HS). Aqueous size exclusion ...
  • water-pollution monitoring using matched spatial filters 

    Almeida, S. P.; Eu, J. K. T. (Optical Society of America, 1976-02)
    Presented are some results obtained from the application of matched spatial filtering techniques to the identification of biological specimens called diatoms (i.e., water algae). A prototype semiautomatic optical processor ...
  • wave operators for the matrix Zakharov-Shabat system 

    Klaus, M.; van der Mee, C. (AIP Publishing, 2010-05)
    In this article, we prove the similarity (and, in the focusing case, the J-unitary equivalence) of the free Hamiltonian and the restriction of the full Hamiltonian to the maximal invariant subspace on which its spectrum ...
  • wave scattering in one dimension with absorption 

    Aktosun, T.; Klaus, M.; van der Mee, C. (AIP Publishing, 1998-04)
    Wave scattering is analyzed in a one-dimensional nonconservative medium governed by the generalized Schrodinger equation d(2) psi/dx(2)+k(2) psi=[ikP(x)+Q(x)]psi, where P(x) and Q(x) are real, integrable potentials with ...
  • We Can Never Do Merely One Thing 

    Cairns, John (EcoRes Forum, 2014-01-22)
    Tunnel vision, or just doing one thing, is not suitable with the idea of ecocentricity. For example, the quick _solution of making ethanol from corn for fuel caused more problems than it solved. The lack of awareness of ...
  • weak hard x-ray emission from two broad absorption line quasars observed with nustar: compton-thick absorption or intrinsic x-ray weakness? 

    Luo, B.; Brandt, W. N.; Alexander, D. M.; Harrison, F. A.; Stern, D.; Bauer, F. E.; Boggs, S. E.; Christensen, F. E.; Comastri, A.; Craig, W. W.; Fabian, A. C.; Farrah, D.; Fiore, F.; Fuerst, F.; Grefenstette, B. W.; Hailey, C. J.; Hickox, R.; Madsen, K. K.; Matt, G.; Ogle, P.; Risaliti, G.; Saez, C.; Teng, S. H.; Walton, D. J.; Zhang, W. W. (IOP Publishing Ltd., 2013-08)
    We present Nuclear Spectroscopic Telescope Array (NuSTAR) hard X-ray observations of two X-ray weak broad absorption line (BAL) quasars, PG 1004+130 (radio loud) and PG 1700+518 (radio quiet). Many BAL quasars appear X-ray ...