Neutrino Mass Sum Rules and Symmetries of the Mass Matrix

Neutrino mass sum rules have recently gained again more attention as a powerful tool to discriminate and test various flavour models in the near future. A related question which was not yet discussed fully satisfactorily was the origin of these sum rules and if they are related to any residual or accidental symmetry. We will address this open issue here systematically and find previous statements confirmed. Namely, that the sum rules are not related to any enhanced symmetry of the Lagrangian after family symmetry breaking but that they are simply the result of a reduction of free parameters due to skillful model building.Comment: 10 pages, no figures, accepted for publication in European Physical Journal

Terahertz conductivity of the heavy-fermion compound UNi2Al3

We have studied the optical properties of the heavy-fermion compound UNi2Al3 at frequencies between 100 GHz and 1 THz (3 cm^-1 and 35 cm^-1), temperatures between 2 K and 300 K, and magnetic fields up to 7 T. From the measured transmission and phaseshift of radiation passing through a thin film of UNi2Al3, we have directly determined the frequency dependence of the real and imaginary parts of the optical conductivity (or permittivity, respectively). At low temperatures the anisotropy of the optical conductivity along the a- and c-axes is about 1.5. The frequency dependence of the real part of the optical conductivity shows a maximum at low temperatures, around 3 cm^-1 for the a-axis and around 4.5 cm^-1 for the c-axis. This feature is visible already at 30 K, much higher than the Neel temperature of 4.6 K, and it does not depend on external magnetic fields as high as 7 T. We conclude that this feature is independent of the antiferromagnetic order for UNi2Al3, and this might also be the case for UPd2Al3 and UPt3, where a similar maximum in the optical conductivity was observed previously.Comment: 7 pages, 9 figure

Incorporating Problem-Based Learning Strategies to Develop Learner Autonomy and Employability Skills in Sports Science Undergraduates

This study investigated the impact of a 12-week problem-based learning (PBL) intervention on three psychological constructs (motivation, locus of control and self-esteem) linked to learner autonomy. Results indicated that there was a significant increase in the students’ intrinsic motivation (P<0.05) and a non-significant shift towards an internal locus of control after the intervention period. Students perceived the benefits of PBL to be the opportunity to work in teams and to consider a wider knowledge base. A short course of PBL was successful in developing learner autonomy and other key employability skills alongside the application of content knowledge

Renormalisation Group Corrections to Neutrino Mass Sum Rules

Neutrino mass sum rules are an important class of predictions in flavour models relating the Majorana phases to the neutrino masses. This leads, for instance, to enormous restrictions on the effective mass as probed in experiments on neutrinoless double beta decay. While up to now these sum rules have in practically all cases been taken to hold exactly, we will go here beyond that. After a discussion of the types of corrections that could possibly appear and elucidating on the theory behind neutrino mass sum rules, we estimate and explicitly compute the impact of radiative corrections, as these appear in general and thus hold for whole groups of models. We discuss all neutrino mass sum rules currently present in the literature, which together have realisations in more than 50 explicit neutrino flavour models. We find that, while the effect of the renormalisation group running can be visible, the qualitative features do not change. This finding strongly backs up the solidity of the predictions derived in the literature, and it thus marks a very important step in deriving testable and reliable predictions from neutrino flavour models.Comment: 25 pages, 3 figures, 39 additional plots; version published in JHE

Environmental Concerns in Water Pricing Policy:Â Â an Application of Data Envelopment Analysis (DEA)

Water management is subject to conflicting economic and environmental objectives, and policymakers require a clear overview of the different outcomes derived from different water management options. The aim of this paper is to assess the efficiency of several irrigation water pricing policies with a special focus on their environmental implications. Irrigation is chosen here as a crucial sector of water use in large parts of southern Europe, where pressure on the resource is expected to increase due to climate change. A novel methodological approach for performing an ex ante analysis of alternative water pricing policies is proposed here, where environmental and technical performance are simultaneously considered. This approach takes place in two steps: the first is a simulation of alternative water policies through a mathematical programming model, and the second is the analysis of results by using the Data Envelopment Analysis (DEA) technique. A case study is applied in Puglia (southern Italy), where irrigation is the primary factor of strategic relevance for policymakers regarding water management. Our results show that on the one hand alternative pricing policies perform similarly in terms of technical efficiency and environmental efficiency. On the other hand, inefficiency appears to depend mainly on technical rather than environmental concerns. According to the assigned weights, through the DEA technique, the highest improvement for inefficient options may be obtained by better labour use. We conclude that the proposed approach may be a comprehensive and versatile framework for water policy analysis, offering a tool for supporting the decision-making process.Irrigation, Policy assessment, Efficiency, Data Envelopment Analysis, Linear Programming

The Costs of Drought: the Exceptional 2007-2008 Case of Barcelona

The drought affecting Catalonia between 2007 and 2008 was the most severe of the last century and serves as a case study for the assessment of the economic costs of such an event. The main focus is the drought affecting the so-called Ter-Llobregat system which serves the Metropolitan area of Barcelona, where most of the population is concentrated (approximately 5.5 million people). The 2007-2008 drought is a good illustrative case study due to its extreme severity and the availability of economic information both on the impacts (damages) and the measures taken. Moreover, important communication campaigns were put into place and led to significant reduction of the demand and the set up of mechanisms for public participation for future water management. Direct costs of the affected sectors, indirect costs of the Catalan economy and non-market welfare losses due to the worsening of the environmental quality and restrictions on water supply to households due to scarcity conditions are reported here. The total losses are estimated at 1,661,000,000 Euros (for a one year period), almost 1% of Catalonian´s GDP. The results of this study point out the need for further research on the estimation of the costs of drought (especially at European level) that needs to be embedded into the assessment of the costs of adaptation to climate change.drought, direct costs, indirect costs, non-market welfare losses, Barcelona

Interplay of Aharonov-Bohm and Berry phases in gate-defined graphene quantum dots

We study the influence of a magnetic flux tube on the possibility to electrostatically confine electrons in a graphene quantum dot. Without magnetic flux tube, the graphene pseudospin is responsible for a quantization of the total angular momentum to half-integer values. On the other hand, with a flux tube containing half a flux quantum, the Aharonov-Bohm phase and Berry phase precisely cancel, and we find a state at zero angular momentum that cannot be confined electrostatically. In this case, true bound states only exist in regular geometries for which states without zero-angular-momentum component exist, while non-integrable geometries lack confinement. We support these arguments with a calculation of the two-terminal conductance of a gate-defined graphene quantum dot, which shows resonances for a disc-shaped geometry and for a stadium-shaped geometry without flux tube, but no resonances for a stadium-shaped quantum dot with a $\pi$-flux tube.Comment: 7 pages, 5 figure