Quantum Superposition Principle and Geometry

If one takes seriously the postulate of quantum mechanics in which physical states are rays in the standard Hilbert space of the theory, one is naturally lead to a geometric formulation of the theory. Within this formulation of quantum mechanics, the resulting description is very elegant from the geometrical viewpoint, since it allows to cast the main postulates of the theory in terms of two geometric structures, namely a symplectic structure and a Riemannian metric. However, the usual superposition principle of quantum mechanics is not naturally incorporated, since the quantum state space is non-linear. In this note we offer some steps to incorporate the superposition principle within the geometric description. In this respect, we argue that it is necessary to make the distinction between a 'projective superposition principle' and a 'decomposition principle' that extend the standard superposition principle. We illustrate our proposal with two very well known examples, namely the spin 1/2 system and the two slit experiment, where the distinction is clear from the physical perspective. We show that the two principles have also a different mathematical origin within the geometrical formulation of the theory.Comment: 10 pages, no figures. References added. V3 discussion expanded and new results added, 14 pages. Dedicated to Michael P. Ryan on the occasion of his sixtieth bithda

Usefulness of gold nanoparticles as labels for the determination of gliadins by immunoaffinity chromatography with light scattering detection

III Encuentro sobre Nanociencia y Nanotecnología de Investigadores y Tecnólogos Andaluce

A study of the Gribov copies in linear covariant gauges in Euclidean Yang-Mills theories

The Gribov copies and their consequences on the infrared behavior of the gluon propagator are investigated in Euclidean Yang-Mills theories quantized in linear covariant gauges. Considering small values of the gauge parameter, it turns out that the transverse component of the gluon propagator is suppressed, while its longitudinal part is left unchanged. A Green function, G_{tr}, which displays infrared enhancement and which reduces to the ghost propagator in the Landau gauge is identified. The inclusion of the dimension two gluon condensate is also considered. In this case, the transverse component of the gluon propagator and the Green function G_{tr} remain suppressed and enhanced, respectively. Moreover, the longitudinal part of the gluon propagator becomes suppressed. A comparison with the results obtained from the studies of the Schwinger-Dyson equations and from lattice simulations is provided.Comment: 20 page

Effectiveness of a recent topical sialogogue in the management of drug-induced xerostomia

Objectives: Use of certain drugs is the most common aetiology of xerostomia. Systemic sialogogues provide a longer effect than topic ones, but also induce relevant side effects. Topical sialogogues, as malic acid, allow a safe use as they induce no systemic side-effects or pharmacological interactions, being especially interesting in cases of mild hyposalivation and oral dryness, mainly the chronic use of xerostomizing drugs. The aim of this study was to evaluate the clinical effect of 1% malic acid in patients affected by xerostomia due to antihypertensives or antidepressants. Study Design: 10 patients with drug-induced xerostomia were prospectively evaluated before and after using malic acid spray during three weeks. Xerostomia Inventory (XI) was used to evaluate subjective improvement. Unstimulated and stimulated salivary flow rates were determinated. Results: Severity significantly decreased, from 38.22 to 31.00 points (p = 0.011) after using the product. 77.8% of subjects did not complain about xerostomia at the end and 66.6% achieved an improvement > 6 points. Unstimulated flow rate singnificantly increased, from 0.163 to 0.226 mL/min (p = 0.021) at the third week. Conclusions: 1% malic acid spray induces some improvement in the management of mild and reversible xerostomia. Carrying out of randomized controlled trials is justified according to this study

Time to ride : time as central to the creation and maintenance of shaded organizations

This study takes a grounded theory approach and examines how time takes on constitutive qualities in a mildly hidden organization or what Scott (2013) categorizes as a shaded organization. The organization is a voluntary recreational cycling group, the Thursday Night Social Ride, lacks clearly identifiable leadership and readily available textual elements. 19 participants of the Thursday Night Social Ride were interviewed for this study. The themes that emerged from the data were time, level of hiddenness of the organization, and the relationship among organizational identification, time and hiddenness. This study proposes that in shaded organizations one of the four flows of CCO, activity coordination or time, plays a larger role in creating and maintaining organization while simultaneously acting as an anchor with which members identify.Communication Studie

The exergy costs of electrical power, cooling, and waste heat from a hybrid system based on a solid oxide fuel cell and an absorption refrigeration system

This paper applies the Exergy Cost Theory (ECT) to a hybrid system based on a 500 kWe solid oxide fuel cell (SOFC) stack and on a vapor-absorption refrigeration (VAR) system. To achieve this, a model comprised of chemical, electrochemical, thermodynamic, and thermoeconomic equations is developed using the software, Engineering Equation Solver (EES). The model is validated against previous works. This approach enables the unit exergy costs (electricity, cooling, and residues) to be computed by a productive structure defined by components, resources, products, and residues. Most importantly, it allows us to know the contribution of the environment and of the residues to the unit exergy cost of the product of the components. Finally, the simulation of different scenarios makes it possible to analyze the impact of stack current density, fuel use, temperature across the stack, and anode gas recirculation on the unit exergy costs of electrical power, cooling, and residues