Spectral splits of neutrinos as a BCS-BEC crossover type phenomenon

We show that the spectral split of a neutrino ensemble which initially consists of electron type neutrinos, is analogous to the BCS-BEC crossover already observed in ultra cold atomic gas experiments. Such a neutrino ensemble mimics the deleptonization burst of a core collapse supernova. Although these two phenomena belong to very different domains of physics, the propagation of neutrinos from highly interacting inner regions of the supernova to the vacuum is reminiscent of the evolution of Cooper pairs between weak and strong interaction regimes during the crossover. The Hamiltonians and the corresponding many-body states undergo very similar transformations if one replaces the pair quasispin of the latter with the neutrino isospin of the former.Comment: 9 pages, 5 figure

Design of a Reconfigurable Multi-Core Architecture for Streaming Applications

This thesis presents design of a reconfigurable multi-processor architecture.The architecture is composed of 9 nodes interconnected to each other through a 3x3 mesh-based Network-on-Chip. The central node of the architecture hosts a RISC processor. This node acts as master of the platform, taking care of the data and task scheduling. The surrounding nodes host a reconfigurable engine and do the actual processing. The system was prototyped on an Altera FPGA device and RTL simulations of the architecture were carried out to ensure the correct functionality of the system. The platform was designed to process streaming applications. As an example of these applications, a finite impulse response filter was mapped on the system. Simulation results showed a speed-up of 6.8x over the same FIR filter implemented on a COFFEE RISC core, while requiring a 20% less resources of similar architecture composed by a homogeneous mesh of COFFEE RISC cores

Antidiabetic potential of salvianolic acid B in multiple low-dose streptozotocin-induced diabetes

Context: Salvianolic acids are the most abundant water-soluble compounds extracted from the herb Salvia miltiorrhiza L. (Lamiaceae) with antioxidant and protective effects. Objective: This study evaluates the antidiabetic effect of salvianolic acid B (Sal B) in multiple low-dose streptozotocin (MLDS)-induced diabetes in rat. Materials and methods: Rats were divided into control, Sal B40-treated control, diabetic, Sal B20-, and Sal B40-treated diabetic groups. Sal B was daily administered at doses of 20 or 40 mg/kg (i.p.), started on third day post-STZ injection for 3 weeks. Serum glucose and insulin level and some oxidative stress markers in pancreas were measured in addition to the oral glucose tolerance test (OGTT), histological assessment, and apoptosis determination. Results: After 3 weeks, treatment of diabetic rats with Sal B20 and Sal B40 caused a significant decrease of the serum glucose (p<0.05-0.01) and improvement of OGTT. Meanwhile, serum insulin was significantly higher in Sal B20- and Sal B40-treated diabetics (p<0.01) and treatment of diabetics with Sal B40 significantly lowered malondialdehyde (MDA) (p<0.05), raised glutathione (GSH) (p<0.05), and activity of catalase (p<0.01) with no significant change of nitrite. Furthermore, the number of pancreatic islets (p<0.05) and their area (p<0.01) was significantly higher and apoptosis reactivity was significantly lower (p<0.05) in the Sal B40-treated diabetic group versus diabetics. Discussion and conclusion: Three-week treatment of diabetic rats with Sal B exhibited antidiabetic activity which is partly exerted via attenuation of oxidative stress and apoptosis and augmentation of antioxidant system. © 2015 Informa Healthcare USA, Inc

Heat transfer enhancement and pressure drop for fin-and-tube compact heat exchangers with delta winglet-type vortex generators

Heat transfer rate, pressure loss and efficiency are considered as the most important parameters in designing compact heat exchangers. Despite different types of heat exchangers, fin-and-tube compact heat exchangers are still common device in different industries due to the diversity of usage and the low space installation need. The efficiency of the compact heat exchanger can be increased by introducing the fins and increasing the heat transfer rate between the surface and the surroundings. Numerous modifications can be applied to the fin surface to increase heat transfer. Delta-winglet vortex generators (VGs) are known to enhance the heat transfer between the energy carrying fluid and the heat transfer surfaces in plate-fin-and-tube banks, but they have drawbacks as well. They increase the pressure loss and this should be considered. In this paper, the thermal efficiency of compact heat exchanger with VGs is investigated in different variations. The angle of attack, the length and horizontal and vertical position of winglet are the main parameters to consider. Numerical analyses are carried out to examine finned tube heat exchanger with winglets at the fin surface in a relatively low Reynolds number flow for the inline tube arrangements. The results showed that the length of the winglet significantly affects the improvement of heat transfer performance of the fin-and-tube compact heat exchangers with a moderate pressure loss penalty. In addition, the results show that the optimization cannot be performed for one criterion only. More parameters should be considered at the same time to run the process properly and improve the heat exchanger efficiency

Field-induced easy-axis softening of quantum ferromagnet with cubic anisotropy

In this work, we study the two-dimensional $S=2$ model that can lead to the well-known cubic single-ion anisotropy along with a ferromagnetic Heisenberg interaction under a perpendicular magnetic field. When the Heisenberg term ($J$) is ignored, this model can be exactly solved with a reshuffled local Hilbert space. A three-fold (two-fold) eigenstate degeneracy is found at $h=0$ ($h=2K$), where $h$ stands for the field strength and $K$ is the strength of cubic anisotropy. Around the second degeneracy point there is a huge gap that separates two low-energy states from the rest three. As we turn on the $J$ term, its leading-order contribution boils down to an effective hard-core bosonic model as $K,h\gg J$. By using the two-dimensional tensor network ansatz we reveal that indeed various ground-state ansatz with different magnetic easy axes possess competing energies. Our finding demonstrates that the easy axes can be "softened" as we turn on the magnetic field for such quantum model with cubic anisotropy, which goes beyond the mean-field analysis. Such easy-axis softening might provide a new measure to control the magnetic orientation for spinful semiconductors.Comment: 10 pages, 5 figures, 1 Tabl