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

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

The challenge of cultural gerontology

Over the last decade, Cultural Gerontology has emerged as one of the most vibrant elements of writing about age (Twigg, J., & Martin, W. (Eds.) (2015). The Routledge handbook of cultural gerontology. London: Routledge). Reflecting the wider Cultural Turn, it has expanded the field of gerontology beyond all recognition. No longer confined to frailty, or the dominance of medical and social welfare perspectives, cultural gerontology addresses the nature and experience of later years in the widest sense. In this review, we will explore how the Cultural Turn, which occurred across the social sciences and humanities in the late 20th century, came to influence age studies. We will analyze the impulses that led to the emergence of the field and the forces that have inhibited or delayed its development. We will explore how cultural gerontology has recast aging studies, widening its theoretical and substantive scope, taking it into new territory intellectually and politically, presenting this in terms of 4 broad themes that characterize the work: subjectivity and identity; the body and embodiment; representation and the visual; and time and space. Finally, we will briefly address whether there are problems in the approach

Localization-dependent charge separation efficiency at an organic/inorganic hybrid interface

By combining complementary optical techniques, photoluminescence and time-resolved excited state absorption, we achieve a comprehensive picture of the relaxation processes in the organic/inorganic hybrid system SP6/ZnO. We identify two long-lived excited states of the organic molecules of which only the lowest energy one, localized on the sexiphenyl backbone of the molecule, is found to efficiently charge separate to the ZnO conduction band or radiatively recombine. The other state, most likely localized on the spiro-linked biphenyl, relaxes only by intersystem crossing to a long-lived, probably triplet state, thus acting as a sink of the excitation and limiting the charge separation efficiency.Comment: 6 pages, 5 figure