Landau level mixing by full spin-orbit interactions

We study a two-dimensional electron gas in a perpendicular magnetic field in the presence of both Rashba and Dresselhaus spin-orbit interactions. Using a Bogoliubov transformation we are able to write an approximate formula for the Landau levels, thanks to the simpler form of the resulting Hamiltonian. The exact numerical calculation of the energy levels, is also made simpler by our formulation. The approximate formula and the exact numerical results show excellent agreement for typical semiconductors, especially at high magnetic fields. We also show how effective Zeeman coupling is modified by spin-orbit interactions.Comment: 5 pages, 5 figure

Effects of different packaging methods on microbial, [chemical] and sensory properties of Nile tilapia (Oreochromis niloticus Linnaeus, 1758) fillets during refrigerator storage

The effect of three different packaging methods including Modified Atmosphere Packaging (MAP), Vacuum Packaging and normal Packaging was investigated on the quality of Nile tilapia fresh fillets stored in the refrigerator's temperature. The packaged samples were examined for 10 days with regard to the changes in chemical (TVN, PV, pH), microbial (total viable count) and sensory evaluations. The results indicated that the samples packed in MAP condition had higher quality than that of other methods at the end of the storage period. In addition, the slower destructive impacts and microbial growth was observed in MAP. The results of present study suggest that packaging tilapia under MAP conditions results in the increase in the durability, storing, and distribution period for fillets

Edge States of Monolayer and Bilayer Graphene Nanoribbons

On the basis of tight-binding lattice model, the edge states of monolayer and bilayer graphene nanoribbons (GNRs) with different edge terminations are studied. The effects of edge-hopping modulation, spin-orbital coupling (SOC), and bias voltage on bilayer GNRs are discussed. We observe the following: (i) Some new extra edge states can be created by edge-hopping modulation for monolayer GNRs. (ii) Intralayer Rashba SOC plays a role in depressing the band energy gap $E_g$ opened by intrinsic SOC for both monolayer and bilayer GNRs. An almost linear dependent relation, i.e., $E_g\sim \lambda_R$, is found. (iii) Although the bias voltage favors a bulk energy gap for bilayer graphene without intrinsic SOC, it tends to reduce the gap induced by intrinsic SOC. (iv) The topological phase of the quantum spin Hall effect can be destroyed completely by interlayer Rashba SOC for bilayer GNRs.Comment: 6 pages, 6 figure

Anisotropic superconductivity of niobium based on its response to non-magnetic disorder

Niobium is one of the most studied superconductors, both theoretically and experimentally. It is tremendously important for applications, and it has the highest superconducting transition temperature, $T_{c}=9.33$ K, of all pure metals. In addition to power applications in alloys, pure niobium is used for sensitive magneto-sensing, radio-frequency cavities, and, more recently, as circuit metallization layers in superconducting qubits. A detailed understanding of its electronic and superconducting structure, especially its normal and superconducting state anisotropies, is crucial for mitigating the loss of quantum coherence in such devices. Recently, a microscopic theory of the anisotropic properties of niobium with the disorder was put forward. To verify theoretical predictions, we studied the effect of disorder produced by 3.5 MeV proton irradiation of thin Nb films grown by the same team and using the same protocols as those used in transmon qubits. By measuring the superconducting transition temperature and upper critical fields, we show a clear suppression of $T_{c}$ by potential (non-magnetic) scattering, which is directly related to the anisotropic order parameter. We obtain a very close quantitative agreement between the theory and the experiment

Identification of Sand flies of the Subgenus Larroussius based on Molecular and Morphological Characters in North Western Iran

Background: The adult female sand flies (Diptera: Psychodidae) of the subgenus Larroussius are important vectors of Leishmania infantum (Kinetoplastida: Tripanosomatidae) in Meshkinshahr district, Northwest of Iran. Four Phle­boto­mus (Larroussius) species are present in this area, i.e. Phlebotomus (Larroussius) kandelakii, P. (La.) major, P. (La.) perfiliewi and P. (La.) tobbi. The objective of the present study was to identify and distinguish the females of P. per­filiewi, P. major and P. tobbi, in this district. Methods: Adult sand flies were collected with sticky papers, CDC light traps, and aspirator in 2006. Individual sand flies of this four species from thirty different locations were characterized morphologically and by comparative DNA se­quences analyses of a fragment of mitochondrial gene Cytochrome b (Cyt b) and nuclear gene Elongation Factor 1- al­pha (EF-1α). PCR amplification was carried out for all three species P. major, P. perfiliewi and P. tobbi in the sub­ge­nus Larroussius. Results: Phylogenetic analyses of P. major populations in this study displayed two different populations and genetic di­ver­sity. Spermathecal segment number, pharyngeal armature and other morphological characters of these three spe­cies were examined and found to present consistent interspecific differences. Conclusion: According to our findings, the phylogeny of Cyt b and EF-1α haplotypes confirms the relationships be­tween P. major, P. tobbi and P. perfiliewi as already defined by their morphological similarities