Duality and the Wu classes. The “Spanier-Whitehead dual” of a spectrum X is the function spectrum (in which S denotes the sphere spectrum) DX = F (X,S) (which exists by Brown representability). It comes equipped with an “evaluation” pairing DX ∧X → S. Write H∗(−) for homology with F2 coefficients. If X is finite, then the induced pairing H−∗(DX)⊗H∗(X)→ F2 is perfect, so there is an isomorphism ...

We investigate the power spectrum of velocity fluctuations in the universe starting from four different measures of velocity: the power spectrum of velocity fluctuations from peculiar velocities of galaxies; the rms peculiar velocity of galaxy clusters; the power spectrum of velocity fluctuations from the power spectrum of density fluctuations in the galaxy distribution; and the bulk velocity f...

The purpose of this study is to determine the fine spectra of the operator for which the corresponding upper and lower triangular matrices A(r, s, t) and B(r, s, t) are on the sequence spaces c and lp, where (0 < p < 1), respectively. Further, we obtain the approximate point spectrum, defect spectrum and compression spectrum on these spaces. Furthermore, we give the graphical representations of...

We report a measurement of the excitation spectrum omega(k) and the static structure factor S(k) of a Bose-Einstein condensate. The excitation spectrum displays a linear phonon regime, as well as a parabolic single-particle regime. The linear regime provides an upper limit for the superfluid critical velocity, by the Landau criterion. The excitation spectrum agrees well with the Bogoliubov spec...

A spectral set is a subset 0 of R with Lebesgue measure 0<+(0)< such that there exists a set 4 of exponential functions which form an orthogonal basis of L(0). The spectral set conjecture of B. Fuglede states that a set 0 is a spectral set if and only if 0 tiles R by translation. We study sets 0 which tile R using a rational periodic tile set S=Z+A, where A (1 N1)Z_ } } } _(1 Nn)Z is finite. We...

Forty-five strains of Shigella were screened for haemagglutinin production and broad-spectrum haemagglutination reaction. Mannose-sensitive haemagglutinin (MSHA) was found in 22 strains [Shigella flexneri (7), S. dysenteriae (7), S. sonnei (3), and S. boydii (5)]. Eighteen strains harboured mannose-resistant haemagglutinin (MRHA), and 8 strains were observed to be non-haemagglutinating to guine...

This paper studies geometric and spectral properties of S-adic shifts and their relation to continued fraction algorithms. Pure discrete spectrum for S-adic shifts and tiling properties of associated Rauzy fractals are established under a generalized Pisot assumption together with a geometric coincidence condition. These general results extend the scope of the Pisot substitution conjecture to t...

determination of boundary surface structures is commonly used for data interpretation. horizontal and vertical derivatives are useful tool for determining the edges boundary. using horizontal and vertical derivative in signal analysis method; that is effective method for interpretation of edges boundary, have been used commercially.in acquisition potential field data, using different methods of...

Anharmonic effects of the absorption and fluorescence spectra of pyridine molecule are studied and analyzed for the two-low lying singlet excited states S(1)((1)B(1)) and S(2)((1)B(2)). The complete active space self-consistent field (CASSCF) method is utilized to compute equilibrium geometries and all 27 vibrational normal-mode frequencies for the ground state and the two excited states. The p...