Towards realistic implementations of a Majorana surface code

Surface codes have emerged as promising candidates for quantum information processing. Building on the previous idea to realize the physical qubits of such systems in terms of Majorana bound states supported by topological semiconductor nanowires, we show that the basic code operations, namely projective stabilizer measurements and qubit manipulations, can be implemented by conventional tunnel conductance probes and charge pumping via single-electron transistors, respectively. The simplicity of the access scheme suggests that a functional code might be in close experimental reach.Comment: 5 pages, 1 p. suppl.mat, PRL in pres

Roadmap to Majorana surface codes

Surface codes offer a very promising avenue towards fault-tolerant quantum computation. We argue that two-dimensional interacting networks of Majorana bound states in topological superconductor/semiconductor heterostructures hold several distinct advantages in that direction, both concerning the hardware realization and the actual operation of the code. We here discuss how topologically protected logical qubits in this Majorana surface code architecture can be defined, initialized, manipulated, and read out. All physical ingredients needed to implement these operations are routinely used in topologically trivial quantum devices. In particular, we show that by means of quantum interference terms in linear conductance measurements, composite single-electron pumping protocols, and gate-tunable tunnel barriers, the full set of quantum gates required for universal quantum computation can be implemented.Comment: 23 pages, 8 figure

Piezo-tolerant natural gas-producing microbes under accumulating pCO2

<p>Background: It is known that a part of natural gas is produced by biogenic degradation of organic matter, but the microbial pathways resulting in the formation of pressurized gas fields remain unknown. Autogeneration of biogas pressure of up to 20 bar has been shown to improve the quality of biogas to the level of biogenic natural gas as the fraction of CO2 decreased. Still, the pCO2 is higher compared to atmospheric digestion and this may affect the process in several ways. In this work, we investigated the effect of elevated pCO2 of up to 0.5 MPa on Gibbs free energy, microbial community composition and substrate utilization kinetics in autogenerative high-pressure digestion. Results: In this study, biogas pressure (up to 2.0 MPa) was batch-wise autogenerated for 268 days at 303 K in an 8-L bioreactor, resulting in a population dominated by archaeal Methanosaeta concilii, Methanobacterium formicicum and Mtb. beijingense and bacterial Kosmotoga-like (31% of total bacterial species), Propioniferax-like (25%) and Treponema-like (12%) species. Related microorganisms have also been detected in gas, oil and abandoned coal-bed reservoirs, where elevated pressure prevails. After 107 days autogeneration of biogas pressure up to 0.50 MPa of pCO2, propionate accumulated whilst CH4 formation declined. Alongside the Propioniferax-like organism, a putative propionate producer, increased in relative abundance in the period of propionate accumulation. Complementary experiments showed that specific propionate conversion rates decreased linearly from 30.3 mg g−1 VSadded day−1 by more than 90% to 2.2 mg g−1 VSadded day−1 after elevating pCO2 from 0.10 to 0.50 MPa. Neither thermodynamic limitations, especially due to elevated pH2, nor pH inhibition could sufficiently explain this phenomenon. The reduced propionate conversion could therefore be attributed to reversible CO2-toxicity. Conclusions: The results of this study suggest a generic role of the detected bacterial and archaeal species in biogenic methane formation at elevated pressure. The propionate conversion rate and subsequent methane production rate were inhibited by up to 90% by the accumulating pCO2 up to 0.5 MPa in the pressure reactor, which opens opportunities for steering carboxylate production using reversible CO2-toxicity in mixed-culture microbial electrosynthesis and fermentation.</p

Health-state utilities in a prisoner population : a cross-sectional survey

Background: Health-state utilities for prisoners have not been described. Methods: We used data from a 1996 cross-sectional survey of Australian prisoners (n = 734). Respondent-level SF-36 data was transformed into utility scores by both the SF-6D and Nichol's method. Socio-demographic and clinical predictors of SF-6D utility were assessed in univariate analyses and a multivariate general linear model. Results: The overall mean SF-6D utility was 0.725 (SD 0.119). When subdivided by various medical conditions, prisoner SF-6D utilities ranged from 0.620 for angina to 0.764 for those with none/mild depressive symptoms. Utilities derived by the Nichol's method were higher than SF-6D scores, often by more than 0.1. In multivariate analysis, significant independent predictors of worse utility included female gender, increasing age, increasing number of comorbidities and more severe depressive symptoms. Conclusion: The utilities presented may prove useful for future economic and decision models evaluating prison-based health programs

Exploring concepts of health with male prisoners in three category-C English prisons

Lay understandings of health and illness have a well established track record and a plethora of research now exists which has examined these issues. However, there is a dearth of research which has examined the perspectives of those who are imprisoned. This paper attempts to address this research gap. The paper is timely given that calls have been made to examine lay perspectives in different geographical locations and a need to re-examine health promotion approaches in prison settings. Qualitative data from thirty-six male sentenced prisoners from three prisons in England were collected. The data was analysed in accordance with Attride-Stirling's (2001) thematic network approach. Although the men's perceptions of health were broadly similar to the general population, some interesting findings emerged which were directly related to prison life and its associated structures. These included access to the outdoors and time out of their prison cell, as well as maintaining relationships with family members through visits. The paper proposes that prisoners' lay views should be given higher priority given that prison health has traditionally been associated with medical treatment and the bio-medical paradigm more generally. It also suggests that in order to fulfil the World Health Organization's (WHO) vision of viewing prisons as health promoting settings, lay views should be recognised to shape future health promotion policy and practice

Sodium lauryl ether sulfate (SLES) degradation by nitrate-reducing bacteria

The online version of this article (doi:10.1007/s00253-017-8212-x) contains supplementary material, which is available to authorized users.The surfactant sodium lauryl ether sulfate (SLES) is widely used in the composition of detergents and frequently ends up in wastewater treatment plants (WWTPs). While aerobic SLES degradation is well studied, little is known about the fate of this compound in anoxic environments, such as denitrification tanks of WWTPs, nor about the bacteria involved in the anoxic biodegradation. Here, we used SLES as sole carbon and energy source, at concentrations ranging from 50 to 1000 mg L1, to enrich and isolate nitrate-reducing bacteria from activated sludge of a WWTP with the anaerobic-anoxic-oxic (A2/O) concept. In the 50 mg L1 enrichment, Comamonas (50%), Pseudomonas (24%), and Alicycliphilus (12%) were present at higher relative abundance, while Pseudomonas (53%) became dominant in the 1000 mg L1 enrichment. Aeromonas hydrophila strain S7, Pseudomonas stutzeri strain S8, and Pseudomonas nitroreducens strain S11 were isolated from the enriched cultures. Under denitrifying conditions, strains S8 and S11 degraded 500 mg L1 SLES in less than 1 day, while strain S7 required more than 6 days. Strains S8 and S11 also showed a remarkable resistance to SLES, being able to grow and reduce nitrate with SLES concentrations up to 40 g L1. Strain S11 turned out to be the best anoxic SLES degrader, degrading up to 41% of 500 mg L1. The comparison between SLES anoxic and oxic degradation by strain S11 revealed differences in SLES cleavage, degradation, and sulfate accumulation; both ester and ether cleavage were probably employed in SLES anoxic degradation by strain S11.This research was supported by the Spanish Ministry of Education and Science (contract project CTQ2007-64324 and 447 CONSOLIDER-CSD 2007-00055). The Regional Government of Castilla y Leon (Ref. GR76) is also gratefully acknowledged. MRD is supported by the WIMEK graduate school (project BAdaptive capacity and functionality of multi-trophic aquatic ecosystems^). AJMS is supported by the Gravitation grant (project 024.002.002) of the Netherlands Ministry of Education, Culture and Science and the Netherlands Science Foundation (NWO). AJMS and AJC are supported by an European ResearchCouncil (ERC) Grant (Project 323009).Thisstudywassupported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. This study was alsosupportedbythePortugueseFoundationforScienceandTechnology (FCT) under the scope of the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462). Joana Alves from University of Minho (Portugal) is acknowledged for support with the molecular techniques.info:eu-repo/semantics/publishedVersio

Moving prison health promotion along: Towards an integrative framework for action to develop health promotion and tackle the social determinants of health

The majority of prisoners are drawn from deprived circumstances with a range of health and social needs. The current focus within ‘prison health’ does not, and cannot, given its predominant medical model, adequately address the current health and well-being needs of offenders. Adopting a social model of health is more likely to address the wide range of health issues faced by offenders and thus lead to better rehabilitation outcomes. At the same time, broader action at governmental level is required to address the social determinants of health (poverty, unemployment and educational attainment) that marginalise populations and increase the likelihood of criminal activities. Within prison, there is more that can be done to promote prisoners’ health if a move away from a solely curative, medical model is facilitated, towards a preventive perspective designed to promote positive health. Here, we use the Ottawa Charter for health promotion to frame public health and health promotion within prisons and to set out a challenging agenda that would make health a priority for everyone, not just ‘health’ staff, within the prison setting. A series of outcomes under each of the five action areas of the Charter offers a plan of action, showing how each can improve health. We also go further than the Ottawa Charter, to comment on how the values of emancipatory health promotion need to permeate prison health discourse, along with the concept of salutogenesis