Tri-Bimaximal Neutrino Mixing from Discrete Symmetry in Extra Dimensions

We discuss a particularly symmetric model of neutrino mixings where, with good accuracy, the atmospheric mixing angle theta_{23} is maximal, theta_{13}=0 and the solar angle satisfies sin^2(theta_{12})=1/3 (Harrison-Perkins-Scott (HPS) matrix). The discrete symmetry A_4 is a suitable symmetry group for the realization of this type of model. We construct a model where the HPS matrix is exactly obtained in a first approximation without imposing ad hoc relations among parameters. The crucial issue of the required VEV alignment in the scalar sector is discussed and we present a natural solution of this problem based on a formulation with extra dimensions. We study the corrections from higher dimensionality operators allowed by the symmetries of the model and discuss the conditions on the cut-off scales and the VEVs in order for these corrections to be completely under control. Finally, the observed hierarchy of charged lepton masses is obtained by assuming a larger flavour symmetry. We also show that, under general conditions, a maximal theta_{23} can never arise from an exact flavour symmetry.Comment: 24 pages, 1 figure, misprints corrected and references adde

Tensor products of subspace lattices and rank one density

We show that, if $M$ is a subspace lattice with the property that the rank one subspace of its operator algebra is weak* dense, $L$ is a commutative subspace lattice and $P$ is the lattice of all projections on a separable infinite dimensional Hilbert space, then the lattice $L\otimes M\otimes P$ is reflexive. If $M$ is moreover an atomic Boolean subspace lattice while $L$ is any subspace lattice, we provide a concrete lattice theoretic description of $L\otimes M$ in terms of projection valued functions defined on the set of atoms of $M$. As a consequence, we show that the Lattice Tensor Product Formula holds for \Alg M and any other reflexive operator algebra and give several further corollaries of these results.Comment: 15 page

Sonographers’ perspectives on research – A worldwide online questionnaire study

Introduction Research has been performed by sonographers (also known as ultrasound reporting radiographers) for many years for improving diagnosis of disease, developing new imaging approaches, and enhancing patient outcomes. Despite this, sonographers’ perspectives on research have not been well studied. To understand the views of sonographers is essential, as they have an important role in the successful implementation of research outcomes during their daily work. The study aimed to explore sonographers’ perspectives on research. Methods This cross-sectional online questionnaire was developed, and pilot tested, before distribution on social media platforms by the research group to sonographers or reporting radiographers in ultrasound worldwide. The questionnaire included 21-items. The link was open for 8 weeks in the spring of 2023. A mix of closed, open and scale questions were used. Informed consent was mandatory, and information about the study and anonymity was presented. Results A total of 165 sonographers participated in the questionnaire of which 66.1 % were from Europe (n = 109), 6.1 % from North America (n = 10), 0.6 % from South America (n = 1), 2.4 % from Asia (n = 4), 13.3 % from Africa (n = 22) and 11.5 % from Oceania (n = 19). A total of 32 % of the participants had performed research. Also, 68.5 % would like to become more involved in research. Conclusion Most sonographers work in large hospitals, and half of them have obtained academic level 7 education. A limited number of sonographers have published peer reviewed papers. Many sonographers expressed an interest in research. This suggests a potential for future development of the sonographers’ role in research. Implications for practice The findings for this study provide insight that could be used to improve research practice for sonographers

Theory and Phenomenology of Neutrino Mixing

We review some fundamental aspects of the theory of neutrino masses and mixing. The results of neutrino oscillation experiments are interpreted as evidence of three-neutrino mixing. Implications for the mixing parameters and the neutrino masses are discussed, with emphasis on the connection with the measurements of the absolute values of neutrino masses in beta decay and neutrinoless double-beta decay experiments and cosmological observations.Comment: 16 pages; talks presented at Tau06 (19-22 September 2006, Pisa, Italy) and HQL06 (16-20 October 2006, Munich, Germany

Yukawa Textures and Anomaly Mediated Supersymmetry Breaking

We present a detailed analysis of how a mixed-anomaly-free U(1) symmetry can be used to both resolve the slepton mass problem associated with Anomaly Mediated Supersymmetry Breaking and generate the fermion mass hierarchy via the Froggatt-Nielsen mechanism. Flavour changing neutral currents problems are evaded by a specific form of the Yukawa textures.Comment: 33 pages, TeX, Uses Harvmac (big) and epsf. Added references and minor changes and corrections. Improved texture discussio

Integration of Cost andWork Breakdown Structures in the Management of Construction Projects

Scope management allows project managers to react when a project underperforms regarding schedule, budget, and/or quality at the execution stage. Scope management can also minimize project changes and budget omissions, as well as improve the accuracy of project cost estimates and risk responses. For scope management to be effective, though, it needs to rely on a robust work breakdown structure (WBS). A robust WBS hierarchically and faithfully reflects all project tasks and work packages so that projects are easier to manage. If done properly, the WBS also allows meeting the project objectives while delivering the project on time, on budget, and with the required quality. This paper analyzes whether the integration of a cost breakdown structure (CBS) can lead to the generation of more robust WBSs in construction projects. Over the last years, some international organizations have standardized and harmonized different cost classification systems (e.g., ISO 12006-2, ISO 81346-12, OmniClass, CoClass, UniClass). These cost databases have also been introduced into building information modeling (BIM) frameworks. We hypothesize that in BIM environments, if these CBSs are used to generate the project WBS, several advantages are gained such as sharper project definition. This enhanced project definition reduces project contradictions at both planning and execution stages, anticipates potential schedule and budget deviations, improves resource allocation, and overall it allows a better response to potential project risks. The hypothesis that the use of CBSs can generate more robust WBSs is tested by the response analysis of a questionnaire survey distributed among construction practitioners and project managers. By means of structural equation modeling (SEM), the correlation (agreement) and perception differences between two 250-respondent subsamples (technical project staff vs. project management staff) are also discussed. Results of this research support the use of CBSs by construction professionals as a basis to generate WBSs for enhanced project management (PM)

Deviation from Bimaximality due to Planck scale effects

We consider the effect of Planck scale operators on neutrino mixing. We assume that GUT scale operators give rise to degenerate neutrino masses with bimaximal mixing. Quantum gravity (Planck scale) effects lead to an effective SU(2)L*U(1) invariant dimension-5 Lagrangian involving neutrino and Higgs fields. This gives rise to additional terms in the neutrino mass matrix on electroweak symmetry breaking. These additional terms can be considered as a perturbation to the GUT scale bi-maximal neutrino mass matrix. We assume that the gravitational interaction is flavour blind and compute the deviations of the three neutrino mixing angles due to the Planck scale effects. We find that the changes in theta13, and theta23 are very small but the change in solar mixing angle theta12 can be as large as 3.5 degrees.Comment: 12 pages and 2 figure

Neutrino Mass Sum-rules in Flavor Symmetry Models

Four different neutrino mass sum-rules have been analyzed: these frequently arise in flavor symmetry models based on the groups A_4, S_4 or T', which are often constructed to generate tri-bimaximal mixing. In general, neutrino mass can be probed in three different ways, using beta decay, neutrino-less double beta decay and cosmology. The general relations between the corresponding three neutrino mass observables are well known. The sum-rules lead to relations between the observables that are different from the general case and therefore only certain regions in parameter space are allowed. Plots of the neutrino mass observables are given for the sum-rules, and analytical expressions for the observables are provided. The case of deviations from the exact sum-rules is also discussed, which can introduce new features. The sum-rules could be used to distinguish some of the many models in the literature, which all lead to the same neutrino oscillation results.Comment: 22 pages, 10 figures; matches the version published in Nuclear Physics

Charged Higgs production from SUSY particle cascade decays at the LHC

We analyze the cascade decays of the scalar quarks and gluinos of the Minimal Supersymmetric extension of the Standard Model, which are abundantly produced at the Large Hadron Collider, into heavier charginos and neutralinos which then decay into the lighter ones and charged Higgs particles, and show that they can have substantial branching fractions. The production rates of these Higgs bosons can be much larger than those from the direct production mechanisms, in particular for intermediate values of the parameter $\tan \beta$, and could therefore allow for the detection of these particles. We also discuss charged Higgs boson production from direct two-body top and bottom squark decays as well as from two- and three-body gluino decays.Comment: 30 pages with 10 figures, latex. Uses axodraw.sty and epsfig.st

SUSTAINABLE LOW ENERGY DESALINATION OF ROAD SALT RUNOFF USING ION EXCHANGE RESINS

Gemstone Team MELTSNaCl is used to deice roads during winter storms, but the resulting salty runoff has detrimental environmental effects. A novel low-energy approach for desalinating snowmelt runoff using ion exchange resins was explored. Strong-acid cation and strong-base anion resins were tested in parallel gravity flow columns to determine their efficacy in removing Na+ and Cl− from saline solutions of varying concentrations (0%, 1%, 5%, 10% w/w). Ion exchange was quantified via pH measurements of column effluent samples. Cation resin capacity was positively correlated with influent Na+ concentration, while removal efficiency was negatively correlated with Na+ concentration. Neither the anion resins’ capacity nor removal efficiency followed any correlation with Cl− concentrations. More 1% influent solution compared to 5% or 10% was required to exhaust both resins. Future research should confirm current findings, test resins in realistic field conditions, explore resin regeneration, and examine engineering efficacy in a field setting