Finite-Temperature Properties of Ba(Zr,Ti)O3_3 Relaxors From First Principles

A first-principles-based technique is developed to investigate properties of Ba(Zr,Ti)O$_3$ relaxor ferroelectrics as a function of temperature. The use of this scheme provides answers to important, unresolved and/or controversial questions, such as: what do the different critical temperatures usually found in relaxors correspond to? Do polar nanoregions really exist in relaxors? If yes, do they only form inside chemically-ordered regions? Is it necessary that antiferroelectricity develops in order for the relaxor behavior to occur? Are random fields and random strains really the mechanisms responsible for relaxor behavior? If not, what are these mechanisms? These {\it ab-initio-based} calculations also leads to a deep microscopic insight into relaxors.Comment: 3 figures + Supplemen

Spatial and temporal variations of phytoplankton population in coastal waters of Hormozgan province (Qeshm and Leangeh)

The relationship between diversity or density of phytoplankton and other marine fisheries sector is of great importance. The study of Spatial and temporal variability of distribution of phytoplankton communities in the coastal waters of the Northern Persian Gulf (QESHM, LENGEH) were studied during 2008. In this study, five groups (47 genera) of phytoplankton include, Bacillariophyceae, Dinophyceae, Cyanophyceae, Crysophyceae and Euglenophyceae were identified. The result showed that Diatoms group (79.6 %) and Rhizosolenia genus (45.5 %), contributed more towards the percentage composition of different groups and genera of phytoplankton at the during Study. The annual changes in relative abundance and Margalef, Shannon, pielu and Simpson indices were estimated, 0.58-2.56, 0.08-0.97, 0.23-2.6, 0.09-0.93 respectively. Multivariate analysis of variance showed that during the study, density and biological indicators of phytoplankton were significant between seasons (p<0.05). The spatial cluster analysis based on similarity coefficients obtained two clusters in the areas studied. According to the results obtained can be concluded that both the area of ecological conditions in ranks are instead moderate. Also, phytoplankton of diversity and richness is good

The Effect of Stevia Rebaudiana on Serum Omentin and Visfatin Level in STZ-Induced Diabetic Rats

Recently the role of adipocytokines in relationship to incidence of diabetes has been demonstrated. One of the medicinal plants that are used in the treatment of diabetes is stevia. This study investigates the effect of stevia on serum omentin and visfatin levels as novel adipocytokines in diabetic induced rats to find potential mechanisms for the anti hyperglycemic effect of stevia. Forty male wistar rats weighing 180–250 g were induced with diabetes by intraperitoneal injection of streptozotocin (STZ). The animals were divided into 5 groups of 8. Rats in group 1 (non-diabetic control) and group 2 (diabetic control) were treated with distilled water, and the rats in the treated groups, group 3 (T250), group 4 (T500), and group 5 (T750) were treated with stevia, gavaged every day at 9 a.m. in doses of 250, 500, and 750 mg/kg, respectively. At the end of the study significant reductions in fasting blood sugar (FBS), the homeostasis model assessment insulin resistance (HOMA-IR), triglyceride (TG), alkaline phosphatase (ALP), and Omentin level were found in groups 3 and 4 in comparison with group 2. Pancreatic histopathology slides demonstrated that stevia extract did not induce any increase in the number of β-cells. The conclusion is that prescription of stevia in the doses of 250 and 500 mg/kg/d decreases the omentin level indirectly via activating insulin sensitivity and lowering blood glucose in STZ-induced diabetic rats. KEYWORDS. Diabetes, omentin, stevia, visfati

Muslims in Australia

Assaults on Muslims in Australia in the wake of the September 11 terrorist attacks have brought the vexed issue of identity in a multicultural society to the fore. Being Muslim in Australia has not been easy, but before the recent events there was a sense among Australian Muslims that the two objects of loyalty could stand side by side. This was clearly evident among a growing number of Australian-born Muslims who knew no other homeland than Australia. That belief is now placed under enormous strain as racist attacks on Mosques and Islamic schools question the 'Australianness' of Muslims

Convection of heat and thermodynamic irreversibilities in two-phase, turbulent nanofluid flows in solar heaters by corrugated absorber plates

The effects of simultaneous implementation of corrugated walls and nanoparticles upon the performance of solar heaters are investigated. Triangular and sinusoidal wall profiles along with varying concentration of nanoparticles are analyzed. The multi-phase mixture and the SST κ-ω models are used to simulate turbulent nanofluid flows inside the corrugated channels. The staggered computational grid is employed for storing the velocity and pressure terms at cell faces and cell center, respectively. The governing equations are first discretized by employing a second-order upwind differencing technique and are then solved by means of pressure-based finite volume approach. The convergence criterion is also presented for the validation of obtained results. The effects of wall profiles and nanoparticle concentration on the pertinent parameters including Nusselt number, pressure drop, performance evaluation criterion (PEC), and thermal and frictional irreversibilities are studied. This reveals that, in general, the triangular duct features superior heat transfer and inferior hydraulic characteristics in comparison with the sinusoidal duct. It is demonstrated that as long as the base fluid (water) is used the highest value of PEC corresponds to the straight duct. Yet, by introducing nanofluids the PEC values of the corrugated ducts exceed those of the straight duct. The analysis further shows that on the basis of the performance evaluation criterion, the sinusoidal duct appears to be a better choice in comparison with the triangular duct. However, the situation is reversed when thermodynamic irreversibilities are considered. It is argued that vortex formation in the two investigated wavy walls and shear layer developed in the triangular case are the essential physical reasons for the observed thermal, hydraulic and entropic behaviors