The correlation energy functional within the GW-RPA approximation: exact forms, approximate forms and challenges

In principle, the Luttinger-Ward Green's function formalism allows one to compute simultaneously the total energy and the quasiparticle band structure of a many-body electronic system from first principles. We present approximate and exact expressions for the correlation energy within the GW-RPA approximation that are more amenable to computation and allow for developing efficient approximations to the self-energy operator and correlation energy. The exact form is a sum over differences between plasmon and interband energies. The approximate forms are based on summing over screened interband transitions. We also demonstrate that blind extremization of such functionals leads to unphysical results: imposing physical constraints on the allowed solutions (Green's functions) is necessary. Finally, we present some relevant numerical results for atomic systems.Comment: 3 figures and 3 tables, under review at Physical Review

Dynamics of inflationary cosmology in TVSD model

Within the framework of a model Universe with time variable space dimensions (TVSD), known as decrumpling or TVSD model, we study TVSD chaotic inflation and obtain dynamics of the inflaton, scale factor and spatial dimension. We also study the quantum fluctuations of the inflaton field and obtain the spectral index and its running in this model. Two classes of examples have been studied and comparisons made with the standard slow-roll formulae. We compare our results with the recent Wilkinson Microwave Anisotropy Probe (WMAP) data.Comment: 18 pages, 3 figures, accepted in Mod. Phys. Lett.

The Temporal Expression of Adipokines During Spinal Fusion

Background Context Adipokines are secreted by white adipose tissue and have been associated with fracture healing. Our goal was to report the temporal expression of adipokines during spinal fusion in an established rabbit model. Purpose Our goal was to report the temporal expression of adipokines during spinal fusion in an established rabbit model. Study Design The study design included a laboratory animal model. Methods New Zealand white rabbits were assigned to either sham surgery (n=2), unilateral posterior spinal fusion (n=14), or bilateral posterior spinal fusion (n=14). Rabbits were euthanized 1–6 and 10 weeks out from surgery. Fusion was evaluated by radiographs, manual palpation, and histology. Reverse transcription-polymerase chain reaction on the bone fusion mass catalogued the gene expression of leptin, adiponectin, resistin, and vascular endothelial growth factor (VEGF) at each time point. Results were normalized to the internal control gene, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) (2^ΔCt), and control bone sites (2^ΔΔCt). Quantitative data were analyzed by two-factor analysis of variance (p\u3c.05). Results Manual palpation scores, radiograph scores, and histologic findings showed progression of boney fusion over time (p Conclusions Leptin expression is likely associated with the maturation phase of bone fusion. Adiponectin and resistin may play a role early on during the fusion process. Our results suggest that leptin expression may be upstream of VEGF expression during spinal fusion, and both appear to play an important role in bone spinal fusion

Heavy metals (Ni, Cd, Pb, Cu) concentrations in seaweed and sediments along the coastal areas of Hormuzgan province (Bandar Abbas and Bandar Lengeh)

Metals concentrations were studied in dominant seaweeds and their adjacent sediments in Bandar Abbas and Bandar Lengeh tidal areas. The status of selected heavy metals (Ni, Cd, Pb, Cu) was determined in sediments and 15 dominant seaweed species including 4 species of Chlorophyta, 4 species of Phaeophyta and 7 species of Rhodophyta. Samples of seaweed and sediment were collected seasonally during November 2007 to August 2008 from intertidal regions of nine sites along the Bandar Abbas and Bandar Lengeh coasts. Powdered samples of sediments and seaweed were digested and analyzed using Atomic Absorption Spectrophotometer (A.A.S). Concentrations of Cu, Pb, Cd, and Ni were 5.24, 20.44, 5.40 and 33.83µg/g -1 dry wt. in sediments. Concentration of these metals in µg/g -1 dry weight in Chlorophyta were 11.11, 25.79, 4.76 and 46.57, in Phaeophyta were 9.18, 17.68, 4.82 and 36.65, and in Rhadophyta were 9.80, 21.03, 4.96 and 50.43, respectively. The marine seaweed species collected during all seasons and sites in Bandar Abbas and Bandar Lengeh were identified as Entromorpha compressa and Padina pavonica, respectively