Relative states, quantum axes and quantum references

We address the problem of measuring the relative angle between two "quantum axes" made out of N1 and N2 spins. Closed forms of our fidelity-like figure of merit are obtained for an arbitrary number of parallel spins. The asymptotic regimes of large N1 and/or N2 are discussed in detail. The extension of the concept "quantum axis" to more general situations is addressed. We give optimal strategies when the first quantum axis is made out of parallel spins whereas the second is a general state made out of two spins.Comment: 6 pages, no figure

Infra-Red Finite Charge Propagation

The Coulomb gauge has a long history and many uses. It is especially useful in bound state applications. An important feature of this gauge is that the matter fields have an infra-red finite propagator in an on-shell renormalisation scheme. This is, however, only the case if the renormalisation point is chosen to be the static point on the mass shell, p = (m, 0, 0, 0). In this letter we show how to extend this key property of the Coulomb gauge to an arbitrary relativistic renormalisation point. This is achieved through the introduction of a new class of gauges of which the Coulomb gauge is a limiting case. A physical explanation for this result is given.Comment: 8 pages, plain TeX, to appear in Modern Physics Letters

Supporting SMEs in designing sustainable business models for energy access for the BoP: a strategic design tool

About 1.4 billion people from the Bottom of the Pyramid (BoP) currently lack sustainable energy services. In these contexts, SMEs and practitioners need to combine feasible technical solutions and appropriate business models. Distributed Renewable Energy (DRE) systems emerge as possible solution to provide small-scale and locally based electricity. DRE can be implemented with sustainable business models (Product-Service Systems – PSS) that shift the business focus from selling products to providing a combination of products and services that are able to fulfil customers’ satisfaction. In this paper we explore the combination of DRE and PSS by presenting a strategic design tool that aims at supporting SMEs and practitioners in designing sustainable business models for energy in the BoP. The tool is presented to map companies operating in a selected context, to position a company’s offers and to explore new business opportunities. Following the testing activities in South Africa and Botswana, the tool finds applications to support idea-generation for designing business models for energy access for the BoP

Modelling international monthly tourism demand at the micro destination level with climate indicators and web-traffic data

We investigate if and how climate indicators and web-traffic data may improve the estimates of demand functions\u2019 parameters, considering specific origins and destinations. Overall, augmented demand functions show better fit and more reliable price and income elasticities whether the demand is measured with arrivals or with overnights. However, heterogeneity stemming from the main type of tourism (business vs. cultural vs. sea and sun) affects both the web-based and the climate indicators better describing tourists demand as well as their optimal lags. Our findings highlight the utility of such prompt and territorial detailed information for local policymakers, showing, however, how sensitive different demand segments are to policy intervention

Does urbanization matter in the expenditure-happiness nexus?

This study aims to improve the regional well-being literature on the so-called “reversal issue” of the expenditure-happiness nexus, accounting for two main sources of heterogeneity: degree of urbanization and individual spending habits. Moreover, we investigate the role of happiness across the entire expenditure distribution using a quantile modelling approach. The results show that satisfaction has a positive, significant and non-linear effect on total expenditure across different urbanization categories. To better investigate the multidimensional nature of happiness, analysis of the nexus is expounded to different satisfaction domains and related spending aggregates offering a comprehensive and complex behavioural profile of individuals

Poverty-happiness nexus: Does the use of regional poverty lines matter?

This analysis aims to provide a comprehensive representation of the role of regional disparities in the nexus between poverty and subjective well-being, by adding the territorial dimension to the definition of poverty conditions. We investigate the nexus using regional poverty lines, including different poverty measures and considering different life domains. The analysis focuses on Italy because of its strong regional socio-economic disparities. Results show that the relevance of being poor on the well-being of citizens is in general higher and significant; the intensity and severity of poverty also change for different life domains. Findings are fundamental in designing local policies against poverty

Optimal signal states for quantum detectors

Quantum detectors provide information about quantum systems by establishing correlations between certain properties of those systems and a set of macroscopically distinct states of the corresponding measurement devices. A natural question of fundamental significance is how much information a quantum detector can extract from the quantum system it is applied to. In the present paper we address this question within a precise framework: given a quantum detector implementing a specific generalized quantum measurement, what is the optimal performance achievable with it for a concrete information readout task, and what is the optimal way to encode information in the quantum system in order to achieve this performance? We consider some of the most common information transmission tasks - the Bayes cost problem (of which minimal error discrimination is a special case), unambiguous message discrimination, and the maximal mutual information. We provide general solutions to the Bayesian and unambiguous discrimination problems. We also show that the maximal mutual information has an interpretation of a capacity of the measurement, and derive various properties that it satisfies, including its relation to the accessible information of an ensemble of states, and its form in the case of a group-covariant measurement. We illustrate our results with the example of a noisy two-level symmetric informationally complete measurement, for whose capacity we give analytical proofs of optimality. The framework presented here provides a natural way to characterize generalized quantum measurements in terms of their information readout capabilities.Comment: 13 pages, 1 figure, example section extende

Combined assimilation of IASI and MLS observations to constrain tropospheric and stratospheric ozone in a global chemical transport model

Accurate and temporally resolved fields of free-troposphere ozone are of major importance to quantify the intercontinental transport of pollution and the ozone radiative forcing. We consider a global chemical transport model (MOdèle de Chimie Atmosphérique à Grande Échelle, MOCAGE) in combination with a linear ozone chemistry scheme to examine the impact of assimilating observations from the Microwave Limb Sounder (MLS) and the Infrared Atmospheric Sounding Interferometer (IASI). The assimilation of the two instruments is performed by means of a variational algorithm (4D-VAR) and allows to constrain stratospheric and tropospheric ozone simultaneously. The analysis is first computed for the months of August and November 2008 and validated against ozonesonde measurements to verify the presence of observations and model biases. Furthermore, a longer analysis of 6 months (July–December 2008) showed that the combined assimilation of MLS and IASI is able to globally reduce the uncertainty (root mean square error, RMSE) of the modeled ozone columns from 30 to 15% in the upper troposphere/lower stratosphere (UTLS, 70–225 hPa). The assimilation of IASI tropospheric ozone observations (1000–225 hPa columns, TOC – tropospheric O₃ column) decreases the RMSE of the model from 40 to 20% in the tropics (30° S–30° N), whereas it is not effective at higher latitudes. Results are confirmed by a comparison with additional ozone data sets like the Measurements of OZone and wAter vapour by aIrbus in-service airCraft (MOZAIC) data, the Ozone Monitoring Instrument (OMI) total ozone columns and several high-altitude surface measurements. Finally, the analysis is found to be insensitive to the assimilation parameters. We conclude that the combination of a simplified ozone chemistry scheme with frequent satellite observations is a valuable tool for the long-term analysis of stratospheric and free-tropospheric ozone

Effect of inhaled bronchodilators on inspiratory capacity and dyspnoea at rest in COPD

It has been shown that patients with chronic obstructive pulmonary disease (COPD) develop dynamic hyperinflation (DH), which contributes to dyspnoea and exercise intolerance. Formoterol, salmeterol and oxitropium have been recommended for maintenance therapy in COPD patients, but their effect on DH has only been assessed for salmeterol. The aim of the present study was to compare the acute effect of four inhaled bronchodilators (salbutamol, formoterol, salmeterol and oxitropium) and placebo on forced expiratory volume in one second, inspiratory capacity, forced vital capacity and dyspnoea in COPD patients. A cross-over, randomised, double-blind, placebo-controlled study was carried out on 20 COPD patients. Patients underwent pulmonary function testing and dyspnoea evaluation, in basal condition and 5, 15, 30, 60 and 120 min after bronchodilator or placebo administration. The results indicate that in chronic obstructive pulmonary disease patients with decreased baseline inspiratory capacity, there was a much greater increase of inspiratory capacity after bronchodilator administration, which correlated closely with the improvement of dyspnoea sensation at rest. For all bronchodilators used, inspiratory capacity reversibility should be tested at 30 min following the bronchodilator. On average, formoterol elicited the greatest increase in inspiratory capacity than the other bronchodilators used, though the difference was significant only with salmeterol and oxitropium. The potential advantage of formoterol needs to be tested in a larger patient population

Mmokolodi solar PV project – Demonstrating sustainable renewable energy system design and potential for Botswana rural electrification

The aim of this paper is to introduce the AU-funded distributed solar photovoltaic (PV) research project currently being implemented at the Mmokolodi Village in Botswana. The paper shall outline the potential of the project for rural electrification and assess system design considerations guaranteeing its sustainability. A descriptive methodology is considered sufficient to capture the complexity of the project's design goal and its sustenance beyond the project time. The inherent complexity cited underlines the need for a holistic system design view embracing technical, social, economical, environmental, and ownership dimensions. These dimensions are substantiated in the paper applying suitable frameworks. Within one of the frameworks, an overview of possible business models is explored, in particular looking at Product-Service Systems and related ownership models as promising approach for project sustainability. The current status of this ongoing research work limits definitive commentary about the expected final result. Whereas valid business case statements for sustaining the Mmokolodi project can already be made, the other sustainability metrics namely feasibility, viability and desirability remain projected goals. The results of this research exemplify the need for interdisciplinary collaboration in sustainable energy research undertakings. The assessments made will help future project implementers to anticipate implementation hurdles proactively. The results will help energy end-users at the Mmokolodi community to access affordable modern energy and assess its desirability. For policy planners these results may shape energy planning to embrace the complexity inherent in the energy planning process