A new bridge between leptonic CP violation and leptogenesis

Flavor effects due to lepton interactions in the early Universe may have played an important role in the generation of the cosmological baryon asymmetry through leptogenesis. If the only source of high-energy CP violation comes from the left-handed leptonic sector, then it is possible to establish a bridge between flavored leptogenesis and low-energy leptonic CP violation. We explore this connection taking into account our present knowledge about low-energy neutrino parameters and the matter-antimatter asymmetry observed in the Universe. In this framework, we find that leptogenesis favors a hierarchical light neutrino mass spectrum, while for quasi-degenerate and inverted hierarchical neutrino masses there is a very narrow allowed window. The absolute neutrino mass scale turns out to be m < 0.1 eV.Comment: 10 pages, 3 figure

Spontaneous leptonic CP violation and nonzero θ13\theta_{13}

We consider a simple extension of the Standard Model by adding two Higgs triplets and a complex scalar singlet to its particle content. In this framework, the CP symmetry is spontaneously broken at high energies by the complex vacuum expectation value of the scalar singlet. Such a breaking leads to leptonic CP violation at low energies. The model also exhibits an $A_4\times Z_4$ flavour symmetry which, after being spontaneously broken at a high-energy scale, yields a tribimaximal pattern in the lepton sector. We consider small perturbations around the tribimaximal vacuum alignment condition in order to generate nonzero values of $\theta_{13}$, as required by the latest neutrino oscillation data. It is shown that the value of $\theta_{13}$ recently measured by the Daya Bay Reactor Neutrino Experiment can be accommodated in our framework together with large Dirac-type CP violation. We also address the viability of leptogenesis in our model through the out-of-equilibrium decays of the Higgs triplets. In particular, the CP asymmetries in the triplet decays into two leptons are computed and it is shown that the effective leptogenesis and low-energy CP-violating phases are directly linked.Comment: 17 pages; 6 figures; references added and typos corrected. Final version to appear in PR

D-string on near horizon geometries and infinite conformal symmetry

We show that the symmetries of effective D-string actions in constant dilaton backgrounds are directly related to homothetic motions of the background metric. In presence of such motions, there are infinitely many nonlinearly realized rigid symmetries forming a loop (or loop like) algebra. Near horizon (AdS) D3 and D1+D5 backgrounds are discussed in detail and shown to provide 2d interacting field theories with infinite conformal symmetry.Comment: 5 pages, revtex, no figures; symmetry transformations for BI action added, coupling of D-string to RR 2-form in D1-D5 background corrected; final version, to appear in Phys. Rev. Let

Effect of electroacupuncture (EA) on gastrointestinal peristaltism in dogs

The article has no abstract

Rossby wave breaking, the upper level jet, and serial clustering of extratropical cyclones in western Europe

Winter 2013/14 was the stormiest on record for the UK and was characterized by recurrent clustering of extratropical cyclones. This clustering was associated with a strong, straight and persistent North Atlantic jet and was also associated with Rossby wave breaking (RWB) on both flanks, pinning the jet in place. The occurrence of RWB and cyclone clustering is further studied in 36 years of the ERA-Interim Reanalysis. Clustering at 55°N is associated with an extended and anomalously strong eddy-driven jet flanked on both sides by RWB. However, clustering at 65(45)°N has a dominance of RWB to the south (north) of the jet, deflecting the jet northward (southward). A positive correlation was found between clustering and RWB occurrence to the north and south of the jet. However, there is considerable spread in these relationships

Observable Electron EDM and Leptogenesis

In the context of the minimal supersymmetric seesaw model, the CP-violating neutrino Yukawa couplings might induce an electron EDM. The same interactions may also be responsible for the generation of the observed baryon asymmetry of the Universe via leptogenesis. We identify in a model-independent way those patterns within the seesaw models which predict an electron EDM at a level probed by planned laboratory experiments and show that negative searches on \tau-> e \gamma decay may provide the strongest upper bound on the electron EDM. We also conclude that a possible future detection of the electron EDM is incompatible with thermal leptogenesis, even when flavour effects are accounted for.Comment: 26 pages, 6 figure

Carbon dots from tryptophan doped glucose for peroxynitrite sensing

Tryptophan doped carbon dots (Trp-CD) were microwave synthesized. The optimum conditions of synthesizing of the Trp-CD were established by response surface multivariate optimization methodologies and were the following: 2.5 g of glucose and 300 mg of tryptophan diluted in 15 mL of water exposed for 5 min to a microwave radiation of 700 W. Trp-CD have an average size of 20 nm, were fluorescent with a quantum yield of 12.4% and the presence of peroxynitrite anion (ONOO−) provokes quenching of the fluorescence. The evaluated analytical methodology for ONOO− detection shows a linear response range from 5 to 25 μM with a limit of detection of 1.5 μM and quantification of 4.9 μM. The capability of the ONOO− quantification was evaluated in standard solutions and in fortified serum samples

Flavored Gauge-Mediation

The messengers of Gauge-Mediation Models can couple to standard-model matter fields through renormalizable superpotential couplings. These matter-messenger couplings generate generation-dependent sfermion masses and are therefore usually forbidden by discrete symmetries. However, the non-trivial structure of the standard-model Yukawa couplings hints at some underlying flavor theory, which would necessarily control the sizes of the matter-messenger couplings as well. Thus for example, if the doublet messenger and the Higgs have the same properties under the flavor theory, the resulting messenger-lepton couplings are parametrically of the same order as the lepton Yukawas, so that slepton mass-splittings are similar to those of minimally-flavor-violating models and therefore satisfy bounds on flavor-violation, with, however, slepton mixings that are potentially large. Assuming that fermion masses are explained by a flavor symmetry, we construct viable and natural models with messenger-lepton couplings controlled by the flavor symmetry. The resulting slepton spectra are unusual and interesting, with slepton mass-splittings and mixings that may be probed at the LHC. In particular, since the new contributions are typically negative, and since they are often larger for the first- and second-generation sleptons, some of these examples have the selectron or the smuon as the lightest slepton, with mass splittings of a few to tens of GeV.Comment: 16 pages v2: Explicit expressions (which are not needed in the analysis) for the pure Yukawa contributions removed. There was an error in some of these expressions in v1. References adde

Evaluation of different formulations of gellan gum-based hydrogels for tissue engineering of intervertebral disc

Gellan gum based-hydrogels present advantageous features for application as acellular and cellular nucleus pulposus (NP) substitutes due to the possibility of fine-tuning its physico-chemical and biological properties. In this study, ionic-crosslinked hydrogel discs were produced by means of mixing a raw and chemically modified material, i.e., high acyl gellan gum (HAGG) and methacrylated low acyl gellan gum (GG-MA), respectively. The hydrogel discs were characterized in terms of its mechanical properties and degradation/swelling ability. The biocompatibility of the different hydrogel formulations was assessed in vitro using NP rabbit cells isolated from the intervertebral disc. The biological performance of the developed gellan gum-based hydrogels formulations was evaluated by: (i) culturing of NP cells in the presence of the hydrogel leachables, and (ii) seeding or encapsulation of the NP cells within the hydrogels. The present work demonstrated that as HAGG content increases, the modulus of the hydrogels decreases. Moreover, the increase of the HAGG content induces a higher weight loss of the GG-MA/HA-GG formulation as compared to GG-MA hydrogel. The in vitro study revealed that hydrogels are non-cytotoxic and support the encapsulation of rabbit NP cells. The methacrylated gellan gum and formulations possessing high acyl gellan gum present tunable properties that may be interesting for application as NP substitutes

Macro/microporous silk fibroin scaffolds with potential for articular cartilage and meniscus tissue engineering applications

This study describes the developmental physicochemical properties of silk fibroin scaffolds derived from high concentration aqueous silk fibroin solutions. The silk fibroin scaffolds were prepared with different initial concentrations (8%, 10%, 12% and 16% (wt%)) and obtained by combining the salt-leaching and freeze-drying methodologies. The results indicated that the antiparallel β-pleated sheet (silk-II) conformation was present in the silk fibroin scaffolds. All the scaffolds possessed macro/micro porous structure. Homogeneous porosity distribution was achieved in all the groups of samples. As the silk fibroin concentration increased from 8% to 16%, the mean porosity decreased from 90.8±0.9% to 79.8±0.3%, and the mean interconnectivity decreased from 97.4±0.5% to 92.3±1.3%. The mechanical properties of the scaffolds exhibited a concentration dependence. The dry state compressive modulus increased from 0.81±0.29 MPa to 15.14±1.70 MPa, and the wet state dynamic storage modulus increased around 20-30 folds at each testing frequencies when the silk fibroin concentration increased from 8% to 16%. The water-uptake ratio decreased by means of increasing silk fibroin concentration. The scaffolds present favorable stability as their structure integrity, morphology and mechanical properties were maintained after in vitro degradation for 30 days. Based on these results, the scaffolds developed in this study are herein proposed to be used in meniscus and cartilage tissue engineering scaffolding.Tissue2Tissue project (PTDC/CTM/105703/2008