309 research outputs found
CKM and Tri-bimaximal MNS Matrices in a SU(5) x (d)T Model
We propose a model based on SU(5) x {}^{(d)}T which successfully gives rise
to near tri-bimaximal leptonic mixing as well as realistic CKM matrix elements
for the quarks. The Georgi-Jarlskog relations for three generations are also
obtained. Due to the {}^{(d)}T transformation property of the matter fields,
the b-quark mass can be generated only when the {}^{(d)}T symmetry is broken,
giving a dynamical origin for the hierarchy between m_{b} and m_{t}. There are
only nine operators allowed in the Yukawa sector up to at least mass dimension
seven due to an additional Z_{12} x Z'_{12} symmetry, which also forbids, up to
some high orders, operators that lead to proton decay. The resulting model has
a total of nine parameters in the charged fermion and neutrino sectors, and
hence is very predictive. In addition to the prediction for \theta_{13} \simeq
\theta_{c}/3 \sqrt{2}, the model gives rise to a sum rule,
\tan^{2}\theta_{\odot} \simeq \tan^{2} \theta_{\odot, \mathrm{TBM}} - {1/2}
\theta_{c} \cos\beta, which is a consequence of the Georgi-Jarlskog relations
in the quark sector. This deviation could account for the difference between
the experimental best fit value for the solar mixing angle and the value
predicted by the tri-bimaximal mixing matrix.Comment: 11 pages; v2: additional references added; minor modifications made;
conclusion unchanged; v3: version to appear in Phys. Lett.
parity violation from discrete symmetries
We consider supersymmetric extensions of the standard model in which the
usual or matter parity gets replaced by another or non- discrete
symmetry that explains the observed longevity of the nucleon and solves the
problem of MSSM. In order to identify suitable symmetries, we develop a
novel method of deriving the maximal symmetry that
satisfies a given set of constraints. We identify parity violating (RPV)
and conserving models that are consistent with precision gauge unification and
also comment on their compatibility with a unified gauge symmetry such as the
Pati-Salam group. Finally, we provide a counter-example to the statement found
in the recent literature that the lepton number violating RPV scenarios must
have term and the bilinear operator of comparable
magnitude.Comment: v2: references added, minor corrections; matches published version in
Nucl. Phys.
Resonant leptogenesis in a predictive SO(10) grand unified model
An SO(10) grand unified model considered previously by the authors featuring
lopsided down quark and charged lepton mass matrices is successfully predictive
and requires that the lightest two right-handed Majorana neutrinons be nearly
degenerate in order to obtain the LMA solar neutrino solution. Here we use this
model to test its predictions for baryogenesis through resonant-enhanced
leptogenesis. With the conventional type I seesaw mechanism, the best
predictions for baryogenesis appear to fall a factor of three short of the
observed value. However, with a proposed type III seesaw mechanism leading to
three pairs of massive pseudo-Dirac neutrinos, resonant leptogenesis is
decoupled from the neutrino mass and mixing issues with successful baryogenesis
easily obtained.Comment: 22 pages including 1 figure; published version with reference adde
Neutrino Mass Models: circa 2008
We review recent developments in theoretical models for neutrino masses and
mixing. Emphases are given to models based on finite group family symmetries.
In particular, we describe one recent model based on SU(5), in which both the
tri-bimaximal neutrino mixing and realistic CKM matrix are generated. We also
discuss two models based on a non-anomalous U(1)_F family symmetry in which the
gauge anomalies are cancelled due to the presence of the right-handed
neutrinos. In one of these models, the seesaw scale can be as low as a TeV; in
the other model, which is based on SUSY SU(5), the U(1)_F symmetry forbids
Higgs-mediated proton decays.Comment: Based on Plenary Talk presented at the Neutrino Oscillation Workshop
(NOW2008), Conca Specchiulla, Italy, September 6-13, 2008; 6 page
Group Theoretical Origin of CP Violation
We propose the complex group theoretical Clebsch-Gordon coefficients as a
novel origin of CP violation. This is manifest in our model based on SU(5)
combined with the T' group as the family symmetry. The complex CG coefficients
in T' lead to explicit CP violation which is thus geometrical in origin. The
predicted CP violation measures in the quark sector are consistent with the
current experimental data. The corrections due to leptonic Dirac CP violating
phase gives the experimental best fit value for the solar mixing angle, and we
also gets the right amount of the baryonic asymmetry.Comment: v1: 4 pages; v2: RGE corrections included giving better agreement
with experiments, abstract shortened; v3: Title of the paper has been
changed, references added, version to appear in Phys. Lett.
Soy protein–gum karaya conjugate: emulsifying activity and rheological behavior in aqueous system and oil in water emulsion
The main objective of this study is to investigate the effects of mixing and conjugation of soy protein isolate (SPI) with gum karaya on the characteristics of the hybrid polymer (protein–gum) in both aqueous systems and oil-in-water (O/W) emulsions. It was hypothesized that the covalent linkage of gum karaya with SPI would improve the emulsifying activity and rheological properties of both polymers. Conjugation occurred under controlled conditions (i.e., 60 °C and 75 % relative humidity, 3 days). The conjugated hybrid polymer produced smaller droplet with better uniformity, higher viscosity and stronger emulsifying activity than native gum karaya, suggesting the conjugated polymer provided a bulkier secondary layer with more efficient coverage around oil droplets, thereby inducing stronger resistance against droplet aggregation and flocculation. Emulsions containing the native gum karaya produced the largest droplet size among all prepared emulsions (D 3,2 = 8.6 μm; D 4,3 = 22.4 μm); while the emulsion containing protein–gum conjugate (1:1 g/g) had the smallest droplet size (D 3,2 = 0.2 μm; D 4,3 = 0.7 μm) with lower polydispersity. The protein–gum conjugate (1:1 g/g) also showed the highest elastic and viscous modulus, the lowest polydispersity (span) and the highest emulsifying activity among all native, mixed and conjugated polymers. Therefore, the percentage of gum karaya used for production of O/W emulsion can be decreased by partially replacing it with the conjugated gum
A multi-targeted approach to suppress tumor-promoting inflammation
Cancers harbor significant genetic heterogeneity and patterns of relapse following many therapies are due to evolved resistance to treatment. While efforts have been made to combine targeted therapies, significant levels of toxicity have stymied efforts to effectively treat cancer with multi-drug combinations using currently approved therapeutics. We discuss the relationship between tumor-promoting inflammation and cancer as part of a larger effort to develop a broad-spectrum therapeutic approach aimed at a wide range of targets to address this heterogeneity. Specifically, macrophage migration inhibitory factor, cyclooxygenase-2, transcription factor nuclear factor-κB, tumor necrosis factor alpha, inducible nitric oxide synthase, protein kinase B, and CXC chemokines are reviewed as important antiinflammatory targets while curcumin, resveratrol, epigallocatechin gallate, genistein, lycopene, and anthocyanins are reviewed as low-cost, low toxicity means by which these targets might all be reached simultaneously. Future translational work will need to assess the resulting synergies of rationally designed antiinflammatory mixtures (employing low-toxicity constituents), and then combine this with similar approaches targeting the most important pathways across the range of cancer hallmark phenotypes
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