Supersymmetric quantum cosmology for Bianchi class A models

The canonical theory of (N=1) supergravity, with a matrix representation for the gravitino covector-spinor, is applied to the Bianchi class A spatially homogeneous cosmologies. The full Lorentz constraint and its implications for the wave function of the universe are analyzed in detail. We found that in this model no physical states other than the trivial "rest frame" type occur.Comment: 10 pages, Revte

Semiclassical approximation to supersymmetric quantum gravity

We develop a semiclassical approximation scheme for the constraint equations of supersymmetric canonical quantum gravity. This is achieved by a Born-Oppenheimer type of expansion, in analogy to the case of the usual Wheeler-DeWitt equation. The formalism is only consistent if the states at each order depend on the gravitino field. We recover at consecutive orders the Hamilton-Jacobi equation, the functional Schrodinger equation, and quantum gravitational correction terms to this Schrodinger equation. In particular, the following consequences are found: (i) the Hamilton-Jacobi equation and therefore the background spacetime must involve the gravitino, (ii) a (many fingered) local time parameter has to be present on $SuperRiem \Sigma$ (the space of all possible tetrad and gravitino fields), (iii) quantum supersymmetric gravitational corrections affect the evolution of the very early universe. The physical meaning of these equations and results, in particular the similarities to and differences from the pure bosonic case, are discussed.Comment: 34 pages, clarifications added, typos correcte

Heats of Mixing Using an Isothermal Titration Calorimeter: Associated Thermal Effects

The correct determination of the energy generated or absorbed in the sample cell of an Isothermal Titration Calorimeter (ITC) requires a thorough analysis of the calorimetric signal. This means the identification and quantification of any thermal effect inherent to the working method. In this work, it is carried out a review on several thermal effects, studied by us in previous work, and which appear when an ITC is used for measuring the heats of mixing of liquids in a continuous mode. These effects are due to: (i) the difference between the temperature of the injected liquid and the temperature of the mixture during the mixing process, (ii) the increase of the liquid volume located in the mixing cell and (iii) the stirring velocity. Besides, methods for the identification and quantification of the mentioned effects are suggested

LiCo1−yMyO2 positive electrodes for rechargeable lithium batteries: II. Nickel substituted materials grown by the citrate method

[Abstract] The layered LiCo1−yNiyO2 microcrystalline powders were synthesized by a sol–gel method using citric acid as a chelating agent in the range 0.2 ≤ y ≤ 0.8. Submicron-sized particles of the precursor were obtained at temperature below 400 °C and microcrystalline powders were grown by thermal treatment at 700 °C for 5 h in air. The carboxylic-based acid functioned such as a fuel, decomposed the homogeneous precipitate of metal complexes at low temperature, and yielded the free impurity LiCo1−yNiyO2 single-phases suitable for electrochemical applications. The synthesized products were characterized by structural, spectroscopic and thermal analyses. FT-IR measurements provide information on the growth process and the final local environment in the cationic sublattice of LiCo1−yNiyO2 solid solution. The electrochemical performance of the synthesized products in rechargeable Li cells was evaluated using non-aqueous solution 1 M LiPF6 in EC-DMC as electrolyte. The electrochemical features of a series of LiCo1−yNiyO2 compounds (0.2 ≤ y ≤ 1.0) are discussed in relation with their synthesis procedure and substitutive amount. The substitution of Ni3+ for Co3+ in LiCo1−yNiyO2 for y = 0.75 shows improvement of the specific capacity at ca. 187 mAh/g upon 32 cycles

On the Effects of a Workplace Fitness Program upon Pain Perception: a Case Study Encompassing Office Workers in a Portuguese Context

INTRODUCTION Office workers share several behavioural patterns: they work seated without moving for long times, they use only a few specific muscles of their arms, wrists and hands, and they keep an overall poor body posture. These working patterns generate musculoskeletal disorders, and produce discomfort or pain. Implementation of a work fitness program is thus a low-cost strategy to reduce/prevent body pain derived from work. The aim of this study was to test the benefits of a workplace fitness program, specifically applied to an administrative department of a Portuguese enterprise. Recall that this type of primary prevention level of musculoskeletal disorders has been seldom applied in Portugal, so this research effort materialized an important contribution to overcome such a gap. METHODS The participants in this study were office workers (n = 29 in the study group, and n = 21 in the control group)-who consistently had reported pain mostly on their back side (neck, posterior back, and dorsal and lumbar zones), wrists and posterior legs. The workplace fitness program consisted of three sessions per week during an 8-month period, with 15 min per session; emphasis was on stretching exercises for the body regions most affected by workers' pain perception. Each participant was requested to point out the injured region, as well as the intensity of pain felt, by using a visual analogue scale. Statistical analyses of the perceived pain data from control and study groups resort to non-parametric hypothesis tests. RESULTS There was a strong evidence that the workplace fitness program applied was effective in reducing workers' pain perception for their posterior back, dorsal and lumbar zones, and for their right wrist (P < 0.05). CONCLUSIONS These results generated are rather promising, so they may efficiently serve as an example for other enterprises in that country-while raising awareness on the important issue of quality of life at the workplace.info:eu-repo/semantics/publishedVersio