1,203 research outputs found
The phonology of name signs: a comparison between the Sign Languages of Uganda, Mali, Adamorobe and The Netherlands
Language Use in Past and Presen
Two-Dimensional Self-Assembly in Diblock Copolymers
Submitted to Phys. Rev. Lett.Diblock copolymers confined to a two-dimensional surface may produce uniform features of macromolecular dimensions (10 â 100 nm). We present a mathematical model for nanoscale pattern
formation in such polymers which captures the dynamic evolution of a solution of poly(styrene)-
b-poly(ethylene oxide), PS-b-PEO, in solvent at an air-water interface. The model has no fitting
parameters and incorporates the effects of surface tension gradients, entanglement or vitrification,
and diffusion. The resultant morphologies are quantitatively compared with experimental data.NS
Flavor coupled with chiral oscillations in the presence of an external magnetic field
By reporting to the Dirac wave-packet prescription where it is formally
assumed the {\em fermionic} nature of the particles, we shall demonstrate that
chiral oscillations implicitly aggregated to the interference between positive
and negative frequency components of mass-eigenstate wave-packets introduce
some small modifications to the standard neutrino flavor conversion formula.
Assuming the correspondent spinorial solutions of a ``modified'' Dirac
equation, we are specifically interested in quantifying flavor coupled with
chiral oscillations for a {\em fermionic} Dirac-{\em type} particle (neutrino)
non-minimally coupling with an external magnetic field {\boldmath}. The
viability of the intermediate wave-packet treatment becomes clear when we
assume {\boldmath} orthogonal/parallel to the direction of the propagating
particle.Comment: 21 page
Upper Limits on Electric and Weak Dipole Moments of W-Boson
The total cross-sections of the reaction e+e- --> W+W-, as measured at LEP-II
at centre-of-mass energies between 183 and 207 GeV are used to derive the upper
limits on the parameters of CP-violating (P-odd and C-even) triple gauge-boson
couplings WW\gamma and WWZ. The 95% CL limits |\widetilde{\kappa}_Z|<0.13 and
|\widetilde{\lambda}_Z|<0.31 are obtained assuming local SU(2)_L x U(1)_Y gauge
invariance. Our results are comparable with the previous ones obtained through
the analysis of the W decay products. We also discuss the upper limits on the
electric dipole moment (EDM) of the W-boson, which follow from the precision
measurements of the electron and neutron EDM.Comment: 9 pages, 4 figure
The pragmatics of articles in Dutch children with specific language impairment
Previous studies have found that the morpho-syntactic aspects of grammatical morphemes, including articles, pose problems for Dutch-speaking children with Specific Language Impairment (SLI). In the present study it is demonstrated that article errors in Dutch children with SLI appear to be modulated by the pragmatic context to some extent. This study examines the pragmatic aspects of articles in 19 6- to 8-year-old children with SLI, comparing the results with those of 26 monolingual typically developing age-matched (TD-AM) and 17 language-matched (TD-LM) children. An elicitation task was used to test the specific discourse-new context (definite articles) and non-specific context (indefinite articles). In both contexts, the SLI group omitted articles more often than the TD-AM group, thus behaving similarly to the younger TD-LM group. The SLI group substituted articles more often than children in both control groups. Many children in the SLI group displayed variable behaviour and relatively many children with SLI used definite articles in non-specific contexts. We conclude that processing limitations in SLI may lead to less stable lexical knowledge of articles and hinder the successful integration of lexical, syntactic and pragmatic information that is required for target-like use of articles
Virus shapes and buckling transitions in spherical shells
We show that the icosahedral packings of protein capsomeres proposed by
Caspar and Klug for spherical viruses become unstable to faceting for
sufficiently large virus size, in analogy with the buckling instability of
disclinations in two-dimensional crystals. Our model, based on the nonlinear
physics of thin elastic shells, produces excellent one parameter fits in real
space to the full three-dimensional shape of large spherical viruses. The
faceted shape depends only on the dimensionless Foppl-von Karman number
\gamma=YR^2/\kappa, where Y is the two-dimensional Young's modulus of the
protein shell, \kappa is its bending rigidity and R is the mean virus radius.
The shape can be parameterized more quantitatively in terms of a spherical
harmonic expansion. We also investigate elastic shell theory for extremely
large \gamma, 10^3 < \gamma < 10^8, and find results applicable to icosahedral
shapes of large vesicles studied with freeze fracture and electron microscopy.Comment: 11 pages, 12 figure
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