Electronic properties of emergent topological defects in chiral pp-wave superconductivity

Chiral $p$-wave superconductors in applied magnetic field can exhibit more complex topological defects than just conventional superconducting vortices, due to the two-component order parameter (OP) and the broken time-reversal symmetry. We investigate the electronic properties of those exotic states, some of which contain clusters of one-component vortices in chiral components of the OP and/or exhibit skyrmionic character in the \textit{relative} OP space, all obtained as a self-consistent solution of the microscopic Bogoliubov-de Gennes equations. We reveal the link between the local density of states (LDOS) of the novel topological states and the behavior of the chiral domain wall between the OP components, enabling direct identification of those states in scanning tunneling microscopy. For example, a skyrmion always contains a closed chiral domain wall, which is found to be mapped exactly by zero-bias peaks in LDOS. Moreover, the LDOS exhibits electron-hole asymmetry, which is different from the LDOS of conventional vortex states with the same vorticity. Finally, we present the magnetic field and temperature dependence of the properties of a skyrmion, indicating that this topological defect can be surprisingly large in size, and can be pinned by an artificially indented non-superconducting closed path in the sample. These features are expected to facilitate the experimental observation of skyrmionic states, thereby enabling experimental verification of chirality in emerging superconducting materials

Hydrothermal alteration of the Kemi layered intrusion

Abstract. The Kemi chromite deposit is located near the towns of Kemi and Tornio (northern Finland). The mineralization is hosted within the mafic-ultramafic Kemi intrusion (~2.4 Ga) that is part of the Tornio–Näränkävaara belt. The main chromite zone is located in the basal part of the intrusion and is enveloped and intercalated by peridotites and bronzites. Hydrothermal alteration has pervasively affected the intrusion mainly in the lower and upper segments, leaving the middle part relatively unaltered. These lithologies can still be identified due to the preservation of their primary textures. The altered ultramafic lithologies had been previously catalogued as cumulate, chlorite, amphibole, serpentine and pyroxene peridotites, amphibole and talc pyroxenites, and serpentinites. Further petrographic observations suggest that the ultramafic rocks experienced at least six episodes of hydrothermal alteration that lead to the replacement of primary minerals to assemblages of serpentine, chlorite, amphibole, carbonate and talc. Evidences in the petrography and mineral chemistry suggests the alteration fluid evolve towards more silica rich compositions. The hydrothermal fluids responsible for Kemi intrusion alterations can be related to the metamorphism of the footwall rocks during the Svecofennian Orogeny. Variations in alteration patterns and mineralogy as well as variations in the mineral chemistry do not correlate with the proximity to the chromitite ore zone

Genetic variability and heterogeneity of venezuelan equine encephalitis virus vector Ochlerotatus taeniorhynchus (Diptera : Culicidae) populations of the Colombian Atlantic coast, based on microsatellite loci

In Colombia, the mosquito Ochlerotatus taeniorhynchus has been identified as an efficient vector of the epidemic-epi-zootic Venezuelan equine encephalitis virus. We evaluated the genetic variability and heterogeneity of this mosquito in Colombian populations using eight microsatellite DNA loci. Two hundred and ten mosquito specimens collected from seven populations of the Colombian Atlantic coast (San Bernardo del Viento, Coveñas, Carta-gena, Barranquilla, Ciénaga, Dibulla, and Riohacha) were analyzed. We found five polymorphic microsatellite loci, with 19 alleles giving 62.5% polymorphism; the mean number of alleles per locus was 3.8. The mean expected heterogeneity ranged from 0.568 to 0.660. Most of the polymorphic microsatellite loci were in Hardy-Wein-berg disequilibrium, due to both deficit and excess of heterozygotes. The Fst statistic gave a total value of 0.0369, reflecting low genetic differentiation among the populations and, as a consequence, a low degree of structuring among them, while gene flow was high (Nm = 6.52); these findings point to genetic homogeneity among these populations. There was no significant linkage disequilibrium between genotype pairs of the various populations. We concluded that this mosquito is distributed in local populations along the Colombian Atlantic coast; these findings will be useful for developing strategies for controlling this vector. © FUNPEC-RP

Design issues and experimental characterization of a continuously-tuned adaptive CMOS LNA

This paper presents the design implementation and experimental characterization of an adaptive Low Noise Amplifier (LNA) intended for multi-standard Radio Frequency (RF) wireless transceivers. The circuit —fabricated in a 90-nm CMOS technology— is a two-stage inductively degenerated common-source topology that combines PMOS varactors with programmable load to make the operation of the circuit continuously tunable. Practical design issues are analyzed, considering the effect of circuit parasitics associated to the chip package and integrated inductors, capacitors and varactors. Experimental measurements show a continuous tuning of NF and Sparameters within the 1.75-2.23GHz band, featuring NF19.6dB and IIP3> −9.8dBm, with a power dissipation < 23mW from a 1-V supply voltage.Ministerio de Ciencia e Innovación (FEDER) TEC2007-67247-C02-01/MICJunta de Andalucía, Consejo Regional de Innovación, ciencia y empresa TIC-253