Inverse spin-s portrait and representation of qudit states by single probability vectors

Using the tomographic probability representation of qudit states and the inverse spin-portrait method, we suggest a bijective map of the qudit density operator onto a single probability distribution. Within the framework of the approach proposed, any quantum spin-j state is associated with the (2j+1)(4j+1)-dimensional probability vector whose components are labeled by spin projections and points on the sphere. Such a vector has a clear physical meaning and can be relatively easily measured. Quantum states form a convex subset of the 2j(4j+3) simplex, with the boundary being illustrated for qubits (j=1/2) and qutrits (j=1). A relation to the (2j+1)^2- and (2j+1)(2j+2)-dimensional probability vectors is established in terms of spin-s portraits. We also address an auxiliary problem of the optimum reconstruction of qudit states, where the optimality implies a minimum relative error of the density matrix due to the errors in measured probabilities.Comment: 23 pages, 4 figures, PDF LaTeX, submitted to the Journal of Russian Laser Researc

Holocentric Chromosomes of Luzula elegans Are Characterized by a Longitudinal Centromere Groove, Chromosome Bending, and a Terminal Nucleolus Organizer Region

The structure of holocentric chromosomes was analyzed in mitotic cells of Luzula elegans. Light and scanning electron microscopy observations provided evidence for the existence of a longitudinal groove along each sister chromatid. The centromere-specific histone H3 variant, CENH3, colocalized with this groove and with microtubule attachment sites. The terminal chromosomal regions were CENH3-negative. During metaphase to anaphase transition, L. elegans chromosomes typically curved to a sickle-like shape, a process that is likely to be influenced by the pulling forces of microtubules along the holocentric axis towards the corresponding microtubule organizing regions. A single pair of 45S rDNA sites, situated distal to Arabidopsis-telomere repeats, was observed at the terminal region of one chromosome pair. We suggest that the 45S rDNA position in distal centromere-free regions could be required to ensure chromosome stability. Copyright (C) 2011 S. Karger AG, Base

Effect of nitrous oxide on cisatracurium infusion demands: a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Recent studies have questioned our previous understanding on the effect of nitrous oxide on muscle relaxants, since nitrous oxide has been shown to potentiate the action of bolus doses of mivacurium, rocuronium and vecuronium. This study was aimed to investigate the possible effect of nitrous oxide on the infusion requirements of cisatracurium.</p> <p>Methods</p> <p>70 ASA physical status I-III patients aged 18-75 years were enrolled in this randomized trial. The patients were undergoing elective surgery requiring general anesthesia with a duration of at least 90 minutes. Patients were randomized to receive propofol and remifentanil by target controlled infusion in combination with either a mixture of oxygen and nitrous oxide (Nitrous oxide/TIVA group) or oxygen in air (Air/TIVA group). A 0.1 mg/kg initial bolus of cisatracurium was administered before tracheal intubation, followed by a closed-loop computer controlled infusion of cisatracurium to produce and maintain a 90% neuromuscular block. Cumulative dose requirements of cisatracurium during the 90-min study period after bolus administration were measured and the asymptotic steady state rate of infusion to produce a constant 90% block was determined by applying nonlinear curve fitting to the data on the cumulative dose requirement during the study period.</p> <p>Results</p> <p>Controller performance, i.e. the ability of the controller to maintain neuromuscular block constant at the setpoint and patient characteristics were similar in both groups. The administration of nitrous oxide did not affect cisatracurium infusion requirements. The mean steady-state rates of infusion were 0.072 +/- 0.018 and 0.066 +/- 0.017 mg * kg-1 * h-1 in Air/TIVA and Nitrous oxide/TIVA groups, respectively.</p> <p>Conclusions</p> <p>Nitrous oxide does not affect the infusion requirements of cisatracurium.</p> <p>Trial registration</p> <p>ClinicalTrials.gov NCT01152905; European Clinical Trials Database at <url>http://eudract.emea.eu.int/2006-006037-41</url>.</p

Are ethnic disparities in HbA1c levels explained by mental wellbeing? Analysis of population-based data from the Health Survey for England

Aims: It is unclear how ethnic differences in HbA1c levels are affected by individual variations in mental wellbeing. Thus, the aim of this study was to assess the extent to which HbA1c disparities between Caucasian and South Asian adults are mediated by various aspects of positive psychological functioning. Methods: Data from the 2014 Health Survey for England was analysed using bootstrapping methods. A total of 3894 UK residents with HbA1c data were eligible to participate. Mental wellbeing was assessed using the Warwick-Edinburgh Mental Well-Being Scale. To reduce bias BMI, blood pressure, diabetes status, and other factors were treated as covariates. Results: Ethnicity directly predicted blood sugar control (unadjusted coefficient -2.15; 95% CI -3.64, -0.67), with Caucasians generating lower average HbA1c levels (37.68 mmol/mol (5.6%)) compared to South Asians (39.87 mmol/mol (5.8%)). This association was mediated by positive mental wellbeing, specifically concerning perceived vigour (unadjusted effect 0.30; 95% CI 0.13, 0.58): South Asians felt more energetic than Caucasians (unadjusted coefficient -0.32; 95% CI -0.49, -0.16), and greater perceived energy predicted lower HbA1c levels (unadjusted coefficient -0.92; 95% CI -1.29, -0.55). This mediator effect accounted for just over 14% of the HbA1c variance, and was negated after adjusting for BMI. Conclusions: Caucasian experience better HbA1c levels compared with their South Asian counterparts. However, this association is partly confounded by individual differences in perceived energy levels, which is implicated in better glycaemic control, and appears to serve a protective function in South Asians

Axial and Radial Forces of Cross-Bridges Depend on Lattice Spacing

Nearly all mechanochemical models of the cross-bridge treat myosin as a simple linear spring arranged parallel to the contractile filaments. These single-spring models cannot account for the radial force that muscle generates (orthogonal to the long axis of the myofilaments) or the effects of changes in filament lattice spacing. We describe a more complex myosin cross-bridge model that uses multiple springs to replicate myosin's force-generating power stroke and account for the effects of lattice spacing and radial force. The four springs which comprise this model (the 4sXB) correspond to the mechanically relevant portions of myosin's structure. As occurs in vivo, the 4sXB's state-transition kinetics and force-production dynamics vary with lattice spacing. Additionally, we describe a simpler two-spring cross-bridge (2sXB) model which produces results similar to those of the 4sXB model. Unlike the 4sXB model, the 2sXB model requires no iterative techniques, making it more computationally efficient. The rate at which both multi-spring cross-bridges bind and generate force decreases as lattice spacing grows. The axial force generated by each cross-bridge as it undergoes a power stroke increases as lattice spacing grows. The radial force that a cross-bridge produces as it undergoes a power stroke varies from expansive to compressive as lattice spacing increases. Importantly, these results mirror those for intact, contracting muscle force production

Unexpectedly high pressure for molecular dissociation in liquid hydrogen by electronic simulation

The study of the high pressure phase diagram of hydrogen has continued with renewed effort for about one century as it remains a fundamental challenge for experimental and theoretical techniques. Here we employ an efficient molecular dynamics based on the quantum Monte Carlo method, which can describe accurately the electronic correlation and treat a large number of hydrogen atoms, allowing a realistic and reliable prediction of thermodynamic properties. We find that the molecular liquid phase is unexpectedly stable, and the transition towards a fully atomic liquid phase occurs at much higher pressure than previously believed. The old standing problem of low-temperature atomization is, therefore, still far from experimental reach

Effect of Virulence Factors on the Photodynamic Inactivation of Cryptococcus neoformans

Opportunistic fungal pathogens may cause an array of superficial infections or serious invasive infections, especially in immunocompromised patients. Cryptococcus neoformans is a pathogen causing cryptococcosis in HIV/AIDS patients, but treatment is limited due to the relative lack of potent antifungal agents. Photodynamic inactivation (PDI) uses the combination of non-toxic dyes called photosensitizers and harmless visible light, which produces singlet oxygen and other reactive oxygen species that produce cell inactivation and death. We report the use of five structurally unrelated photosensitizers (methylene blue, Rose Bengal, selenium derivative of a Nile blue dye, a cationic fullerene and a conjugate between poly-L-lysine and chlorin(e6)) combined with appropriate wavelengths of light to inactivate C. neoformans. Mutants lacking capsule and laccase, and culture conditions that favoured melanin production were used to probe the mechanisms of PDI and the effect of virulence factors. The presence of cell wall, laccase and melanin tended to protect against PDI, but the choice of the appropriate photosensitizers and dosimetry was able to overcome this resistance.Fundação de Amparo à Pesquisa do Estado de São Paulo (2010/13313–9