Neutrino masses and mixing in A4 models with three Higgs doublets

We study neutrino masses and mixing in the context of flavor models with A4 symmetry, three scalar doublets in the triplet representation, and three lepton families. We show that there is no representation assignment that yields a dimension-five mass operator consistent with experiment. We then consider a type-I seesaw with three heavy right-handed neutrinos, explaining in detail why it fails, and showing with a numerical example that agreement with the present neutrino oscillation data can be recovered with the inclusion of dimension-three heavy neutrino mass terms that break softly the A4 symmetry.Comment: 10 pages, RevTex, 3 figures. v2: much expanded section on softly broken A4; refs adde

Models with three Higgs doublets in the triplet representations of A(4) or S-4

We consider the quark sector of theories containing three scalar SU(2)(L) doublets in the triplet representation of A(4) (or S-4) and three generations of quarks in arbitrary A(4) (or S-4) representations. We show that for all possible choices of quark field representations and for all possible alignments of the Higgs vacuum expectation values that can constitute global minima of the scalar potential, it is not possible to obtain simultaneously nonvanishing quark masses and a nonvanishing CP-violating phase in the Cabibbo-Kobayashi-Maskawa quark mixing matrix. As a result, in this minimal form, models with three scalar fields in the triplet representation of A(4) or S-4 cannot be extended to the quark sector in a way consistent with experiment

Constraining multi-Higgs flavour models

To study a flavour model with a non-minimal Higgs sector one must first define the symmetries of the fields; then identify what types of vacua exist and how they may break the symmetries; and finally determine whether the remnant symmetries are compatible with the experimental data. Here we address all these issues in the context of flavour models with any number of Higgs doublets. We stress the importance of analysing the Higgs vacuum expectation values that are pseudo-invariant under the generators of all subgroups. It is shown that the only way of obtaining a physical CKM mixing matrix and, simultaneously, non-degenerate and non-zero quark masses is requiring the vacuum expectation values of the Higgs fields to break completely the full flavour group, except possibly for some symmetry belonging to baryon number. The application of this technique to some illustrative examples, such as the flavour groups Delta(27), A4 and S3, is also presented.Comment: 13 pages, 3 figures, title and abstract changed, comments and references added; matches version to appear in The European Physical Journal

A Rare Case of Bilateral Proptosis

A 65-year-old man presented with a 2-year history of severe bilateral proptosis, palpable lymphadenopathy and moderate hepatosplenomegaly. A blood test was positive for hepatitis C infection. CT showed palpebral infiltrative lesions with regional progression through the temporal and masticatory spaces to the pharynx and hypopharynx causing almost complete airway obstruction. A palpebral biopsy was consistent with low-grade Bcl-2+ extra-nodal MALT non-Hodgkin B-cell lymphoma. The patient received six cycles of rituximab-based chemotherapy with clinical remission at 9-month follow-up. Bilateral proptosis is a rare presentation of several diseases. When brain CT excludes cavernous sinus pathology, thyroid ophthalmopathy or haematological malignancy should be considered

The effect of Water in Diesel Nanoemulsion on Light-Duty Diesel Vehicle

Exploratory data analysis (EDA) was performed to determine the effect of a mass fraction of 8% (W8) and 16% (W16) water in diesel nanoemulsions (WiDE) at 0.375:1 formulation to water mass ratio (Fn:W) over diesel EN590 (MD). Tests were executed on a Jaguar X-Type 2.2D Sport, using an Inertia 400 chassis dynamometer, at engine loads (%Load) from 9.02% to 66.67%. Vehicle tests were characterized by changes in indicated air to fuel ratio (AFRIND) due to changes in oxygen level (%O2) found in WiDE; constant air to fuel ratio (AFR) on all vehicle test range (VTR) due to vehicle error; changes in WiDE operational temperature (WOT) to match diesel density and viscosity; and changes in intake air temperature (IAT) due to changes in ambient conditions. The results showed that thermal efficiency changes (%ΔTE) are directly proportional to engine load changes to absolute throttle position changes ratio (Δ[Load:ATP]) and intake air temperature changes (%ΔIAT), and inversely proportional to fuel rate mass changes (%ΔFRm). The Δ[Load:ATP] of the technical correct data (TCD) means (x̅) for W8 and W16 over MD were 2.0149:1 and 2.1318:1, while for the adjusted TCD (TCDADJ) were 2.0706:1 and 2.5075:1 meaning that WiDE had better combustion efficiency than MD. %ΔTE (TCDADJ) means (x̅) at engine loads (%Load) from 12.294% to 55.686%, for W8 and W16 over MD, were 5.351% and 7.209%, at lower WOT than MD, i.e., at %ΔFRm of 2.327% and 5.018%, for %ΔLoad of 4.437% and 7.498%, %ΔIAT of 4.796% and 14.010%, and fuel rail pressure changes (%ΔFRP) of 1.418% and 2.532%, respectively. The TCDADJ means (x̅) changes of nitrogen oxide (NOx), carbon dioxide (%CO2), carbon monoxide (CO) and particulate matter (PM) for W8 over MD were -9.036%, -3.829%, -33.896%, and -73.337%, and for W16 over MD were -10.530%, -3.937%, -80.191%, and -90.778%, respectively. Model C-2 (loess regression method) shows that the %TE means (x̅) and probability (95% CI), at the same %Load and FRm, for MD, W8 and W16 were 13.210% ±0.165%, 13.518% ±0.132% and 13.569% ±0.144%, meaning there is a significant difference between WiDE and MD, but no significant difference between both WiDE. The research shows a positive effect of WiDE over MD on light-duty diesel vehicles (LDDV), but further work needs to be performed to determine, with high level of confidence, the adjusted TCD changes of other engine perfomance variables, fuel rate (FR) costs, FR savings, and exhaust gas emissions (EGE)

Data on kleptoplast light-response curves

<p>Data on kleptoplast light-response curves</p

The Photoprotective Behavior of a Motile Benthic Diatom as Elucidated from the Interplay Between Cell Motility and Physiological Responses to a Light Microgradient Using a Novel Experimental Setup

It has long been hypothesized that benthic motile pennate diatoms use phototaxis to optimize photosynthesis and minimize photoinhibitory damage by adjusting their position within vertical light gradients in coastal benthic sediments. However, experimental evidence to test this hypothesis remains inconclusive, mainly due to methodological difficulties in studying cell behavior and photosynthesis over realistic spatial microscale gradients of irradiance and cell position. In this study, a novel experimental approach was developed and used to test the hypothesis of photosynthesis optimization through motility, based on the combination of single-cell in vivo chlorophyll fluorometry and microfluidic chips. The approach allows the concurrent study of behavior and photosynthetic activity of individual cells of the epipelic diatom species Craspedostauros britannicus exposed to a light microgradient of realistic dimensions, simulating the irradiance and distance scales of light microgradients in benthic sediments. Following exposure to light, (i) cells explored their light environment before initiating light-directed motility; (ii) cells used motility to lower their light dose, when exposed to the highest light intensities; and (iii) motility was combined with reversible non-photochemical quenching, to allow cells to avoid photoinhibition. The results of this proof-of-concept study not only strongly support the photoprotective nature of photobehavior in the studied species but also revealed considerable variability in how individual cells reacted to a light microgradient. The experimental setup can be readily applied to study motility and photosynthetic light responses of other diatom species or natural assemblages, as well as other photoautotrophic motile microorganisms, broadening the toolset for experimental microbial ecology research