Superfluidity in the interior-gap states

We investigate superfluidity in the interior-gap states proposed by Liu and Wilczek. At weak coupling, we find the {\em gapless} interior-gap state unstable in physically accessible regimes of the parameter space, where the superfluid density is shown to be always negative. We therefore conclude that the spatially-uniform interior-gap phase is extremely unstable unless it is fully gapped; in this case, however, the state is rather similar to conventional BCS states.Comment: To appear in Physical Review

Ferromagnetic/superconducting proximity effect in La0.7Ca0.3MnO3 / YBa2Cu3O7 superlattices

We study the interplay between magnetism and superconductivity in high quality YBa2Cu3O7 (YBCO) / La0.7Ca0.3MnO3(LCMO)superlattices. We find evidence for the YBCO superconductivity depression in presence of the LCMO layers. We show that due to its short coherence length superconductivity survives in the YBCO down to much smaller thickness in presence of the magnetic layer than in low Tc superconductors. We also find that for a fixed thickness of the superconducting layer, superconductivity is depressed over a thickness interval of the magnetic layer in the 100 nm range. This is a much longer length scale than that predicted by the theory of ferromagnetic/superconducting proximity effect.Comment: 10 pages + 5 figures, submitted to Phys. Rev.

Proximity effect, quasiparticle transport, and local magnetic moment in ferromagnet-d-wave superconductor junctions

The proximity effect, quasiparticle transport, and local magnetic moment in ferromagnet--d-wave superconductor junctions with {110}-oriented interface are studied by solving self-consistently the Bogoliubov-de Gennes equations within an extended Hubbard model. It is found that the proximity induced order parameter oscillates in the ferromagnetic region. The modulation period is shortened with the increased exchange field while the oscillation amplitude is depressed by the interfacial scattering. With the determined superconducting energy gap, a transfer matrix method is proposed to compute the subgap conductance within a scattering approach. Many novel features including the zero-bias conductance dip and splitting are exhibited with appropriate values of the exchange field and interfacial scattering strength. The conductance spectrum can be influenced seriously by the spin-flip interfacial scattering. In addition, a sizable local magnetic moment near the {110}-oriented surface of the d-wave superconductor is discussed.Comment: 10 pages, 16 ps-figures, to appear in Phys. Rev.

Dinâmica populacional de Pseudococcidae (hemiptera) em videiras no Vale do São Francisco.

O objetivo do trabalho foi estudar a dinâmica de cochonilhas farinhentas em videiras de diferentes áreas de cultivo em Petrolina-PE

Ticks on Didelphis albiventris from a Cerrado area in the Midwestern Brazil.

This experiment studied tick fauna associated to Didelphis albiventris Lund 1840 from a Cerrado area (Mato Grosso do Sul State, non-adjoining to Pantanal) inserted in a pasture and agricultural activities matrix, with few natural preserved forest patches. Authors also summarized data on ticks parasitizing Didelphis spp. in Brazil, and discussed infestation patterns in different biomes and locations. Study took place in Cervinho Farm, Bandeirantes Municipality. For captures, Tomahawk-like traps were distributed along two forest patches (30 each) during five nights. Captures occurred monthly (July/2013 to September/2014), sampling both fragments on alternate months. Animals were sedated and ticks were collected and stored in vials containing ethanol (70%) for identification. 51 D. albiventris were captured in 15 campaigns. Tick prevalence was 100%, and 49.5% of the animals were co-infested by two or more tick species. Four parasitizing species were found: Amblyomma sculptum Berlese, 1888 (78 nymphs), Ixodes loricatus Neumann, 1899 (56 adults), Amblyomma dubitatum Neumann, 1899 (45 nymphs), Amblyomma coelebs Neumann, 1899 (32 nymphs) and Amblyomma sp. (123 larvae). A. sculptum was the most abundant tick, but most frequent species were A. coelebs and A. dubitatum, followed by I. loricatus. Co-occurrences of more than two species were observed among all tick pairs. D. albiventris usually presents high prevalence of tick infestation. However, this study presented 100% prevalence. Knowledge of host-parasite relation and interactions between different ticks that coexist on a same host are essential, since such interaction may favor pathogen dissemination. This is of special relevance regarding D. albiventris, known for participating in maintenance of ecological cycles of Spotted Fever Group rickettsiae

Differences in genotype and virulence among four multidrug-resistant <i>Streptococcus pneumoniae</i> isolates belonging to the PMEN1 clone

We report on the comparative genomics and characterization of the virulence phenotypes of four &lt;i&gt;S. pneumoniae&lt;/i&gt; strains that belong to the multidrug resistant clone PMEN1 (Spain&lt;sup&gt;23F&lt;/sup&gt; ST81). Strains SV35-T23 and SV36-T3 were recovered in 1996 from the nasopharynx of patients at an AIDS hospice in New York. Strain SV36-T3 expressed capsule type 3 which is unusual for this clone and represents the product of an in vivo capsular switch event. A third PMEN1 isolate - PN4595-T23 - was recovered in 1996 from the nasopharynx of a child attending day care in Portugal, and a fourth strain - ATCC700669 - was originally isolated from a patient with pneumococcal disease in Spain in 1984. We compared the genomes among four PMEN1 strains and 47 previously sequenced pneumococcal isolates for gene possession differences and allelic variations within core genes. In contrast to the 47 strains - representing a variety of clonal types - the four PMEN1 strains grouped closely together, demonstrating high genomic conservation within this lineage relative to the rest of the species. In the four PMEN1 strains allelic and gene possession differences were clustered into 18 genomic regions including the capsule, the blp bacteriocins, erythromycin resistance, the MM1-2008 prophage and multiple cell wall anchored proteins. In spite of their genomic similarity, the high resolution chinchilla model was able to detect variations in virulence properties of the PMEN1 strains highlighting how small genic or allelic variation can lead to significant changes in pathogenicity and making this set of strains ideal for the identification of novel virulence determinant

Pseudogap and Superconducting Fluctuation in High-Tc Cuprates: Theory beyond 1-loop Approximation

The pseudogap phenomena induced by the SC fluctuation are investigated in details. We perform a calculation beyond the 1-loop approximation. The SC fluctuation is microscopically derived on the basis of the repulsive Hubbard model. The vertex corrections are collected in the infinite order with use of the quasi-static approximation. The single-particle excitations, NMR 1/T_{1}T, spin susceptibility and superconducting transition temperature are discussed. The important role of the vertex correction is pointed out for the single particle spectral function. On the other hand, the validity of the 1-loop order theory is confirmed for other quantities. We shed light on the essential nature of SC fluctuation leading to the pseudogap from the comparison with spin and charge fluctuations