Magnetic field induced singlet - triplet phase transition in quasi one-dimensional organic superconductors

We propose a theoretical model of quasi-one-dimensional superconductors, with attractive electron-electron interactions dominant in the singlet d-wave channel and sub-dominant in the p-wave channel. We discuss, in the mean field approximation, the effect of a magnetic field applied perpendicularly to the direction of the lowest conductivity. The lowest free energy phase corresponds to a singlet d-wave symmetry in low fields, but to a triplet symmetry in high fields. A first order singlet-triplet phase transition is expected at moderate applied fields of a few teslas. We propose to ascribe the recent critical field and NMR experimental data, observed in superconducting (TMTSF)2ClO4 to such an effect.Comment: 6 pages, 2 figures, accepted in EP

Coexistence of Superconductivity and Spin Density Wave orderings in the organic superconductor (TMTSF)_2PF_6

The phase diagram of the organic superconductor (TMTSF)_2PF_6 has been revisited using transport measurements with an improved control of the applied pressure. We have found a 0.8 kbar wide pressure domain below the critical point (9.43 kbar, 1.2 K) for the stabilisation of the superconducting ground state featuring a coexistence regime between spin density wave (SDW) and superconductivity (SC). The inhomogeneous character of the said pressure domain is supported by the analysis of the resistivity between T_SDW and T_SC and the superconducting critical current. The onset temperature T_SC is practically constant (1.20+-0.01 K) in this region where only the SC/SDW domain proportion below T_SC is increasing under pressure. An homogeneous superconducting state is recovered above the critical pressure with T_SC falling at increasing pressure. We propose a model comparing the free energy of a phase exhibiting a segregation between SDW and SC domains and the free energy of homogeneous phases which explains fairly well our experimental findings.Comment: 13 pages, 10 figures, revised v: fig.9 added, section 4.2 rewritten, accepted v: sections 4&5 improve

Solving the Richardson equations for Fermions

Forty years ago Richardson showed that the eigenstates of the pairing Hamiltonian with constant interaction strength can be calculated by solving a set of non-linear coupled equations. However, in the case of Fermions these equations lead to singularities which made them very hard to solve. This letter explains how these singularities can be avoided through a change of variables making the Fermionic pairing problem numerically solvable for arbitrary single particle energies and degeneracies.Comment: 5 pages, 4 figures, submitted to Phys.Rev.

Soliton Wall Superlattice in Quasi-One-Dimensional Conductor (Per)2Pt(mnt)2

We suggest a model to explain the appearance of a high resistance high magnetic field charge-density-wave (CDW) phase, discovered by D. Graf et al. [Phys. Rev. Lett. v. 93, 076406 (2004)] in (Per)2Pt(mnt)2. In particular, we show that the Pauli spin-splitting effects improve the nesting properties of a realistic quasi-one-dimensional electron spectrum and, therefore, a high resistance Peierls CDW phase is stabilized in high magnetic fields. In low and very high magnetic fields, a periodic soliton wall superlattice (SWS) phase is found to be a ground state. We suggest experimental studies of the predicted phase transitions between the Peierls and SWS CDW phases in (Per)2Pt(mnt)2 to discover a unique SWS phase.Comment: 10 pages, 3 figures. Submitted to Physical Review Letters (February 19, 2007

Quantum Limit in a Parallel Magnetic Field in Layered Conductors

We show that electron wave functions in a quasi-two-dimensional conductor in a parallel magnetic field are always localized on conducting layers. Wave functions and electron spectrum in a quantum limit, where the "sizes" of quasi-classical electron orbits are of the order of nano-scale distances between the layers, are determined. AC infrared measurements to investigate Fermi surfaces and to test Fermi liquid theory in Q2D organic and high-Tc materials in high magnetic fields, H = 10-45 T, are suggested.Comment: 9 pages, 2 figures; Submitted to Physical Review Letter

A multifaceted strategy using mobile technology to assist rural primary healthcare doctors and frontline health workers in cardiovascular disease risk management: protocol for the SMARTHealth India cluster randomised controlled trial

BACKGROUND: Blood Pressure related disease affected 118 million people in India in the year 2000; this figure will double by 2025. Around one in four adults in rural India have hypertension, and of those, only a minority are accessing appropriate care. Health systems in India face substantial challenges to meet these gaps in care, and innovative solutions are needed. METHODS: We hypothesise that a multifaceted intervention involving capacity strengthening of primary healthcare doctors and non-physician healthcare workers through use of a mobile device-based clinical decision support system will result in improved blood pressure control for individuals at high risk of a cardiovascular disease event when compared with usual healthcare. This intervention will be implemented as a stepped wedge, cluster randomised controlled trial in 18 primary health centres and 54 villages in rural Andhra Pradesh involving adults aged ≥40 years at high cardiovascular disease event risk (approximately 15,000 people). Cardiovascular disease event risk will be calculated based on World Health Organisation/International Society of Hypertension's region-specific risk charts. Cluster randomisation will occur at the level of the primary health centres. Outcome analyses will be conducted blinded to intervention allocation. EXPECTED OUTCOMES: The primary study outcome is the difference in the proportion of people meeting guideline-recommended blood pressure targets in the intervention period vs. the control period. Secondary outcomes include mean reduction in blood pressure levels; change in other cardiovascular disease risk factors, including body mass index, current smoking, reported healthy eating habits, and reported physical activity levels; self-reported use of blood pressure and other cardiovascular medicines; quality of life (using the EQ-5D); and cardiovascular disease events (using hospitalisation data). Trial outcomes will be accompanied by detailed process and economic evaluations. SIGNIFICANCE: The findings are likely to inform policy on a scalable strategy to overcome entrenched inequities in access to effective healthcare for under-served populations in low and middle income country settings. TRIAL REGISTRATION: Clinical Trial Registry India CTRI/2013/06/003753

Machine learning algorithms distinguish discrete digital emotional fingerprints for web pages related to back pain

Back pain is the leading cause of disability worldwide. Its emergence relates not only to the musculoskeletal degeneration biological substrate but also to psychosocial factors; emotional components play a pivotal role. In modern society, people are significantly informed by the Internet; in turn, they contribute social validation to a “successful” digital information subset in a dynamic interplay. The Affective component of medical pages has not been previously investigated, a significant gap in knowledge since they represent a critical biopsychosocial feature. We tested the hypothesis that successful pages related to spine pathology embed a consistent emotional pattern, allowing discrimination from a control group. The pool of web pages related to spine or hip/knee pathology was automatically selected by relevance and popularity and submitted to automated sentiment analysis to generate emotional patterns. Machine Learning (ML) algorithms were trained to predict page original topics from patterns with binary classification. ML showed high discrimination accuracy; disgust emerged as a discriminating emotion. The findings suggest that the digital affective “successful content” (collective consciousness) integrates patients’ biopsychosocial ecosystem, with potential implications for the emergence of chronic pain, and the endorsement of health-relevant specific behaviors. Awareness of such effects raises practical and ethical issues for health information providers

Novel Phases in the Field Induced Spin Density Wave State in (TMTSF)_2PF_6

Magnetoresistance measurements on the quasi one-dimensional organic conductor (TMTSF)_2PF_6 performed in magnetic fields B up to 16T, temperatures T down to 0.12K and under pressures P up to 14kbar have revealed new phases on its P-B-T phase diagram. We found a new boundary which subdivides the field induced spin density wave (FISDW) phase diagram into two regions. We showed that a low-temperature region of the FISDW diagram is characterized by a hysteresis behavior typical for the first order transitions, as observed in a number of studies. In contrast to the common believe, in high temperature region of the FISDW phase diagram, the hysteresis and, hence, the first order transitions were found to disappear. Nevertheless, sharp changes in the resistivity slope are observed both in the low and high temperature domains indicating that the cascade of transitions between different subphases exists over all range of the FISDW state. We also found that the temperature dependence of the resistance (at a constant B) changes sign at about the same boundary. We compare these results with recent theoretical models.Comment: LaTex, 4 pages, 4 figure

VIM-1 Metallo-β-lactamase in Acinetobacter baumannii

In 2004 and 2005, 5 metallo-β-lactamase (MBL)-positive Acinetobacter baumannii isolates were found in 2 Greek hospitals. Isolates were unrelated and carried blaVIM-1 in a class 1 integron; blaOXA-51- and blaOXA-58-like carbapenemase genes were also detected. VIM-1 MBL in Acinetobacter spp. causes concern, given the increasing resistance of this species

Impact of age at type 2 diabetes mellitus diagnosis on mortality and vascular complications: systematic review and meta-analyses

AIMS/HYPOTHESIS: Few studies examine the association between age at diagnosis and subsequent complications from type 2 diabetes. This paper aims to summarise the risk of mortality, macrovascular complications and microvascular complications associated with age at diagnosis of type 2 diabetes. METHODS: Data were sourced from MEDLINE and All EBM (Evidence Based Medicine) databases from inception to July 2018. Observational studies, investigating the effect of age at diabetes diagnosis on macrovascular and microvascular diabetes complications in adults with type 2 diabetes were selected according to pre-specified criteria. Two investigators independently extracted data and evaluated all studies. If data were not reported in a comparable format, data were obtained from authors, presented as minimally adjusted ORs (and 95% CIs) per 1 year increase in age at diabetes diagnosis, adjusted for current age for each outcome of interest. The study protocol was recorded with PROSPERO International Prospective Register of Systematic Reviews (CRD42016043593). RESULTS: Data from 26 observational studies comprising 1,325,493 individuals from 30 countries were included. Random-effects meta-analyses with inverse variance weighting were used to obtain the pooled ORs. Age at diabetes diagnosis was inversely associated with risk of all-cause mortality and macrovascular and microvascular disease (all p < 0.001). Each 1 year increase in age at diabetes diagnosis was associated with a 4%, 3% and 5% decreased risk of all-cause mortality, macrovascular disease and microvascular disease, respectively, adjusted for current age. The effects were consistent for the individual components of the composite outcomes (all p < 0.001). CONCLUSIONS/INTERPRETATION: Younger, rather than older, age at diabetes diagnosis was associated with higher risk of mortality and vascular disease. Early and sustained interventions to delay type 2 diabetes onset and improve blood glucose levels and cardiovascular risk profiles of those already diagnosed are essential to reduce morbidity and mortality. Graphical abstract