We analyse public domain time-series photometric observations of 30 known and candidate binary post-AGB stars for measuring pulsation and orbital periods. We derive periodicities for 17 stars for the first time in the literature. Besides identifying five new RV Tauri type pulsating variables (three with the RVb phenomenon, i.e. long-term changes of the mean brightness), we find multiply periodi...

This study presents an automatic method for estimating antenatal amniotic fluid (AF) volume from two-dimensional ultrasound (US) images, which is important indicator of fetal well-being. estimation AF (AFV) requires automated segmentation the pocket, a challenging task due to its amorphous features and US artifacts, such as reverberation, shadowing, particle noise, signal dropout. Recently, AF-...

The single rung t-J ladder is analyzed in a mean field theory using Gutzwiller renormalization of the matrix elements to account for strong correlation. The spin liquid (RVB) state at half-filling evolves into a superconducting state upon doping. The order parameter has a modified d-wave character. A lattice of weakly coupled ladders should show a superconducting phase transition. PACS: 71.27.+...

In this paper, we do a complete classification of valence-bond crystals (VBCs) on the kagomé lattice based on general arguments of symmetry only and thus identify many new VBCs for different unit cell sizes. For the spin1/2 Heisenberg antiferromagnet, we study the relative energetics of competing gapless spin liquids (SLs) and VBC phases within the class of Gutzwillerprojected fermionic wave fu...

The discovery of high-Tc superconductivity in the cuprates, and the observation that strong correlations are important in connection with these compounds has led to a tremendous interest in understanding the physics of strongly correlated electronic models. In particular the two simplest models for strongly correlated electrons, namely the Hubbard and t−J models, have been the subject of intens...

We reconsider the problem of separation of spin and charge in one dimensional quantum antiferromagnets. We show that spin and charge separation in one dimensional strongly correlated systems cannot be described by the slave boson or fermion representation within any perturbative treatment of the interactions between the slave holons and slave spinons. The constraint of single occupancy must be ...

The density response of a doped Mott-Hubbard insulator is discussed starting from the t-J model in a slave boson 1/N representation. In leading order O(1) the density fluctuation spectra N(q,ω) are determined by an undamped collective mode at large momentum transfer, in striking disagreement with results obtained by exact diagonalization, which reveal a very broad dispersive peak, reminescent o...

The metallic state of the molecular conductor β-(meso-DMBEDT-TTF)2X (DMBEDT-TTF = 2-(5,6-dihydro-1,3-dithiolo[4,5-b][1,4]dithiin-2-ylidene)-5,6-dihydro5,6-dimethyl-1,3-dithiolo[4,5-b][1,4]dithiin, X = PF6, AsF6) is transformed into the checkerboard-type charge-ordered state at around 75–80 K with accompanying metalinsulator (MI) transition on the anisotropic triangular lattice. With lowering te...

Shading techniques should be wavelength dependent, a fact which has traditionally been ignored in computer graphics: colour is usually represented in t.erms of an RGB coordinate system, which is inappropriat.e and has demonstrable problems. The use of spectral refl ectances for materials in place of the RGB values in t.he shading comput.at.ions would solve these problems. Our techniqne proposes...

The 2-dimensional (2D) Hybrid theory obtained from the coupling of ionization energy (EI) based Fermi liquid (FL) resistivity model in c-axis and resonating-valence-bond (RVB) based effective t-J model is used to analyse the Hall resistances (R (ab) H , R (c) H ) of optimally doped as well as oxygen-deficient YBa2Cu3O7−δ single crystals. It is shown that R (ab) H ∝ 1/T and R (c) H is independen...