37 research outputs found

    The cosmological origin of Higgs particles

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    A proposal of the cosmological origin of Higgs particles is given. We show, that the Higgs field could be created from the vacuum quantum conformal fluctuation of Anti-de Sitter space-time, the spontaneous breaking of vacuum symmetry, and the mass of Higgs particle are related to the cosmological constant of our universe,especially the theoretical estimated mass mH_{H} of Higgs particles is mH=2μ2_{H}=\sqrt{-2\mu ^{2}} =Λ/π\sqrt{|\Lambda /\pi}.Comment: 7 pages,no figure

    Staggering of the Nuclear Charge Radii in a Superfluid Model with Good Particle Number

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    A simple superfluid model with an effective four body interaction of monopole pairing type is used to explain the staggering of the charge radii in the isotope chains. The contribution of deformation and of the particle number projection are analyzed for the Sn isotopes. Good results are obtained for the staggering parameters and neutron pairing energies.Comment: RevTex, 19 pages and 4 postscript figures uuencoded and attached. To appear in Phys. Rev.

    Dicationic Alkylammonium Bromide Gemini Surfactants. Membrane Perturbation and Skin Irritation

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    Dicationic alkylammonium bromide gemini surfactants represent a class of amphiphiles potentially effective as skin permeation enhancers. However, only a limited number of studies has been dedicated to the evaluation of the respective cytotoxicity, and none directed to skin irritation endpoints. Supported on a cell viability study, the cytotoxicity of gemini surfactants of variable tail and spacer length was assessed. For this purpose, keratinocyte cells from human skin (NCTC 2544 cell line), frequently used as a model for skin irritation, were employed. The impact of the different gemini surfactants on the permeability and morphology of model vesicles was additionally investigated by measuring the leakage of calcein fluorescent dye and analyzing the NMR spectra of 31P, respectively. Detail on the interaction of gemini molecules with model membranes was also provided by a systematic differential scanning calorimetry (DSC) and molecular dynamics (MD) simulation. An irreversible impact on the viability of the NCTC 2544 cell line was observed for gemini concentrations higher than 25 mM, while no cytotoxicity was found for any of the surfactants in a concentration range up to 10 mM. A higher cytotoxicity was also found for gemini surfactants presenting longer spacer and shorter tails. The same trend was obtained in the calorimetric and permeability studies, with the gemini of longest spacer promoting the highest degree of membrane destabilization. Additional structural and dynamical characterization of the various systems, obtained by 31P NMR and MD, provide some insight on the relationship between the architecture of gemini surfactants and the respective perturbation mechanism

    The Commonwealth Caribbean and Europe: The End of the Affair?

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    © 2015 The Round Table Ltd. Abstract: The institutional relationship between the Commonwealth Caribbean and the European Union (EU) dates back to the mid-1970s, when the Lomé Convention was signed. The agreement was seen as a high water mark in First–Third World relations. However, since then the bond has come under concerted pressure. The consequence is that today the particularism that underpinned relations for so long has almost vanished and the EU is beginning to treat the Caribbean like any other relatively marginal region of the world. The article evaluates the reasons for this change, in particular: the scrapping of the trade protocols; the erosion of African, Caribbean and Pacific (ACP) preference due to free trade agreements signed by the EU; the refocusing of EU development policy towards the least developed countries; and the split in the ACP group with the creation of an ill-designed regional Economic Partnership Agreement. The article places these changes into starker relief by assessing briefly the deepening links between the United Kingdom Overseas Territories and the EU. However, as the article highlights, this link will neither reboot nor sustain the more important Commonwealth Caribbean–EU relationship
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