The impact of the internet on the pricing strategies of the European low cost airlines

This study seeks to analyse the price determination of low cost airlines in Europe and the effect that Internet has on this strategy. The outcomes obtained reveal that both users and companies benefit from the use of ICTs in the purchase and sale of airline tickets: the Internet allows consumers to increase their bargaining power comparing different airlines and choosing the most competitive flight, while companies can easily check the behaviour of users to adapt their pricing strategies using internal information. More than 2500 flights of the largest European low cost airlines have been used to carry out the study. The study revealed that the most significant variables for understanding pricing strategies were the number of rivals, the behaviour of the demand and the associated costs. The results indicated that consumers should buy their tickets before 25 days prior to departure.

Adsorbent density impact on gas storage capacities

In the literature, different approaches, terminologies, concepts and equations are used for calculating gas storage capacities. Very often, these approaches are not well defined, used and/or determined, giving rise to significant misconceptions. Even more, some of these approaches, very much associated with the type of adsorbent material used (e.g., porous carbons or new materials such as COFs and MOFs), impede a suitable comparison of their performances for gas storage applications. We review and present the set of equations used to assess the total storage capacity for which, contrarily to the absolute adsorption assessment, all its experimental variables can be determined experimentally without assumptions, ensuring the comparison of different porous storage materials for practical application. These material-based total storage capacities are calculated by taking into account the excess adsorption, the bulk density (ρbulk) and the true density (ρtrue) of the adsorbent. The impact of the material densities on the results are investigated for an exemplary hydrogen isotherm obtained at room temperature and up to 20 MPa. It turns out that the total storage capacity on a volumetric basis, which increases with both, ρbulk and ρtrue, is the most appropriate tool for comparing the performance of storage materials. However, the use of the total storage capacities on a gravimetric basis cannot be recommended, because low material bulk densities could lead to unrealistically high gravimetric values.

Impact of economic crisis on mental health of migrant workers: what happened with migrants who came to Spain to work?

Objectives: To assess changes in mental health in a sample of migrant workers after the eruption of the economic crisis in Spain. Methods: 318 migrant workers were interviewed. Mental health, sociodemographic, and economic crisis related variables were obtained through face-to-face (2008) and phone (2011) interviews. Prevalence of poor mental health (PMH) was compared (2011–2008) and multivariate logistic regression models were fitted. Results: Change in prevalence of PMH was higher in men (aOR 4.63; 95 % CI 2.11–10.16). Subgroups of men showing the largest detrimental mental health effects were: unemployed, with low salaries (≤1,200 euros) and those reporting family burden. An increase of PMH was found in women, without significant associations. Conclusions: Mental health of migrant workers in Spain has worsened during the economic crisis.

Intimate partner violence among women in Spain: the impact of regional-level male unemployment and income inequality

Background: Intimate partner violence (IPV) against women is a complex worldwide public health problem. There is scarce research on the independent effect on IPV exerted by structural factors such as labour and economic policies, economic inequalities and gender inequality. Objective: To analyse the association, in Spain, between contextual variables of regional unemployment and income inequality and individual women’s likelihood of IPV, independently of the women’s characteristics. Method: We conducted multilevel logistic regression to analyse cross-sectional data from the 2011 Spanish Macrosurvey of Gender-based Violence which included 7898 adult women. The first level of analyses was the individual women’ characteristics and the second level was the region of residence. Results: Of the survey participants, 12.2% reported lifetime IPV. The region of residence accounted for 3.5% of the total variability in IPV prevalence. We determined a direct association between regional male long-term unemployment and IPV likelihood (P = 0.007) and between the Gini Index for the regional income inequality and IPV likelihood (P < 0.001). Women residing in a region with higher gender-based income discrimination are at a lower likelihood of IPV than those residing in a region with low gender-based income discrimination (odds ratio = 0.64, 95% confidence intervals: 0.55–0.75). Conclusions: Growing regional unemployment rates and income inequalities increase women’s likelihood of IPV. In times of economic downturn, like the current one in Spain, this association may translate into an increase in women’s vulnerability to IPV.

Convergence analysis and validation of low cost distance metrics for computational cost reduction of the Iterative Closest Point algorithm

The Iterative Closest Point algorithm (ICP) is commonly used in engineering applications to solve the rigid registration problem of partially overlapped point sets which are pre-aligned with a coarse estimate of their relative positions. This iterative algorithm is applied in many areas such as the medicine for volumetric reconstruction of tomography data, in robotics to reconstruct surfaces or scenes using range sensor information, in industrial systems for quality control of manufactured objects or even in biology to study the structure and folding of proteins. One of the algorithm’s main problems is its high computational complexity (quadratic in the number of points with the non-optimized original variant) in a context where high density point sets, acquired by high resolution scanners, are processed. Many variants have been proposed in the literature whose goal is the performance improvement either by reducing the number of points or the required iterations or even enhancing the complexity of the most expensive phase: the closest neighbor search. In spite of decreasing its complexity, some of the variants tend to have a negative impact on the final registration precision or the convergence domain thus limiting the possible application scenarios. The goal of this work is the improvement of the algorithm’s computational cost so that a wider range of computationally demanding problems from among the ones described before can be addressed. For that purpose, an experimental and mathematical convergence analysis and validation of point-to-point distance metrics has been performed taking into account those distances with lower computational cost than the Euclidean one, which is used as the de facto standard for the algorithm’s implementations in the literature. In that analysis, the functioning of the algorithm in diverse topological spaces, characterized by different metrics, has been studied to check the convergence, efficacy and cost of the method in order to determine the one which offers the best results. Given that the distance calculation represents a significant part of the whole set of computations performed by the algorithm, it is expected that any reduction of that operation affects significantly and positively the overall performance of the method. As a result, a performance improvement has been achieved by the application of those reduced cost metrics whose quality in terms of convergence and error has been analyzed and validated experimentally as comparable with respect to the Euclidean distance using a heterogeneous set of objects, scenarios and initial situations.

Implementation of non-local boundary layer schemes in the Regional Atmospheric Modeling System and its impact on simulated mesoscale circulations

This paper proposes the implementation of different non-local Planetary Boundary Layer schemes within the Regional Atmospheric Modeling System (RAMS) model. The two selected PBL parameterizations are the Medium-Range Forecast (MRF) PBL and its updated version, known as the Yonsei University (YSU) PBL. YSU is a first-order scheme that uses non-local eddy diffusivity coefficients to compute turbulent fluxes. It is based on the MRF, and improves it with an explicit treatment of the entrainment. With the aim of evaluating the RAMS results for these PBL parameterizations, a series of numerical simulations have been performed and contrasted with the results obtained using the Mellor and Yamada (MY) scheme, also widely used, and the standard PBL scheme in the RAMS model. The numerical study carried out here is focused on mesoscale circulation events during the summer, as these meteorological situations dominate this season of the year in the Western Mediterranean coast. In addition, the sensitivity of these PBL parameterizations to the initial soil moisture content is also evaluated. The results show a warmer and moister PBL for the YSU scheme compared to both MRF and MY. The model presents as well a tendency to overestimate the observed temperature and to underestimate the observed humidity, considering all PBL schemes and a low initial soil moisture content. In addition, the bias between the model and the observations is significantly reduced moistening the initial soil moisture of the corresponding run. Thus, varying this parameter has a positive effect and improves the simulated results in relation to the observations. However, there is still a significant overestimation of the wind speed over flatter terrain, independently of the PBL scheme and the initial soil moisture used, even though a different degree of accuracy is reproduced by RAMS taking into account the different sensitivity tests.

Theoretical Rationalization of the Singlet–Triplet Gap in OLEDs Materials: Impact of Charge-Transfer Character

New materials for OLED applications with low singlet–triplet energy splitting have been recently synthesized in order to allow for the conversion of triplet into singlet excitons (emitting light) via a Thermally Activated Delayed Fluorescence (TADF) process, which involves excited-states with a non-negligible amount of Charge-Transfer (CT). The accurate modeling of these states with Time-Dependent Density Functional Theory (TD-DFT), the most used method so far because of the favorable trade-off between accuracy and computational cost, is however particularly challenging. We carefully address this issue here by considering materials with small (high) singlet–triplet gap acting as emitter (host) in OLEDs and by comparing the accuracy of TD-DFT and the corresponding Tamm-Dancoff Approximation (TDA), which is found to greatly reduce error bars with respect to experiments thanks to better estimates for the lowest singlet–triplet transition. Finally, we quantitatively correlate the singlet–triplet splitting values with the extent of CT, using for it a simple metric extracted from calculations with double-hybrid functionals, that might be applied in further molecular engineering studies.