Spectral properties of incommensurate charge-density wave systems

The concept of frustrated phase separation is applied to investigate its consequences for the electronic structure of the high T_c cuprates. The resulting incommensurate charge density wave (CDW) scattering is most effective in creating local gaps in k-space when the scattering vector connects states with equal energy. Starting from an open Fermi surface we find that the resulting CDW is oriented along the (10)- and (or) (01)-direction which allows for a purely one-dimensional or a two-dimensional ``eggbox type'' charge modulation. In both cases the van Hove singularities are substantially enhanced, and the spectral weight of Fermi surface states near the M-points, tends to be suppressed. Remarkably, a leading edge gap arises near these points, which, in the eggbox case, leaves finite arcs of the Fermi surface gapless. We discuss our results with repect to possible consequences for photoemission experiments

Encoding algebraic power series

Algebraic power series are formal power series which satisfy a univariate polynomial equation over the polynomial ring in n variables. This relation determines the series only up to conjugacy. Via the Artin-Mazur theorem and the implicit function theorem it is possible to describe algebraic series completely by a vector of polynomials in n+p variables. This vector will be the code of the series. In the paper, it is then shown how to manipulate algebraic series through their code. In particular, the Weierstrass division and the Grauert-Hironaka-Galligo division will be performed on the level of codes, thus providing a finite algorithm to compute the quotients and the remainder of the division.Comment: 35 page

Restrictions on the coherence of the ultrafast optical emission from an electron-hole pairs condensate

We report on the transfer of coherence from a quantum-well electron-hole condensate to the light it emits. As a function of density, the coherence of the electron-hole pair system evolves from being full for the low density Bose-Einstein condensate to a chaotic behavior for a high density BCS-like state. This degree of coherence is transfered to the light emitted in a damped oscillatory way in the ultrafast regime. Additionally, the photon field exhibits squeezing properties during the transfer time. We analyze the effect of light frequency and separation between electron and hole layers on the optical coherence. Our results suggest new type of ultrafast experiments for detecting electron-hole pair condensation.Comment: 4 pages,3 figures, to be published in Physical Review Letters. Minor change

Challenging the status quo: women's experiences of opting for a home birth in Andalucia, Spain

Objective To explore the perceptions, beliefs and attitudes of women who opted for a home birth in Andalusia (Spain). Background Home birth is currently an unusual choice among Spanish women. It is not an option covered by the Spanish National Health Service and women who opt for a home birth have to pay for an independent midwife. Design A qualitative study with a phenomenological approach was adopted. All participants who took part in this study had chosen to have a home birth and given written consent to take part in the study. Methods Data collection was conducted in 2015–16. Face-to-face, semi-structured interviews were undertaken with women who chose a home birth in the last 5 years. Findings The sample consisted of thirteen women. Seven themes were created through analysis: 1. Getting informed about home birth; 2. Home birth as a choice, despite feeling unsupported; 3. The best way to have a personalized and a physiological birth; 4. Seeking a healing and empowering experience 5. The need for emotional safety, establishing a relationship and trusting the midwife; 6. Preparing for birth and working on fears; 7. Inequality of access (because of financial implications). Conclusions Women opted to plan birth at home because they wanted a personalised birth and control over their decision-making in labour, which they felt would not have been afforded to them in hospital settings. Andalusian maternity care leaders should strive to ensure that all pregnant women receive respectful and high-quality personalised care, by appropriately trained staff, both in the hospital and in the community

Comparative Genomics Analysis of a New Exiguobacterium Strain from Salar de Huasco Reveals a Repertoire of Stress-Related Genes and Arsenic Resistance

Indexación: Web of Science; Scopus.The Atacama Desert hosts diverse ecosystems including salt flats and shallow Andean lakes. Several heavy metals are found in the Atacama Desert, and microorganisms growing in this environment show varying levels of resistance/tolerance to copper, tellurium, and arsenic, among others. Herein, we report the genome sequence and comparative genomic analysis of a new Exiguobacterium strain, sp. SH31, isolated from an altiplanic shallow athalassohaline lake. Exiguobacterium sp. SH31 belongs to the phylogenetic Group II and its closest relative is Exiguobacterium sp. S17, isolated from the Argentinian Altiplano (95% average nucleotide identity). Strain SH31 encodes a wide repertoire of proteins required for cadmium, copper, mercury, tellurium, chromium, and arsenic resistance. Of the 34 Exiguobacterium genomes that were inspected, only isolates SH31 and S17 encode the arsenic efflux pump Acr3. Strain SH31 was able to grow in up to 10 mM arsenite and 100 mM arsenate, indicating that it is arsenic resistant. Further, expression of the ars operon and acr3 was strongly induced in response to both toxics, suggesting that the arsenic efflux pump Acr3 mediates arsenic resistance in Exiguobacterium sp. SH31.http://journal.frontiersin.org/article/10.3389/fmicb.2017.00456/ful