27,870 research outputs found
Search for Lorentz Violation in a Short-Range Gravity Experiment
An experimental test of the Newtonian inverse square law at short range has
been used to set limits on Lorentz violation in the pure gravity sector of the
Standard-Model Extension. On account of the planar test mass geometry,
nominally null with respect to inverse square forces, the limits derived for
the SME coefficients of Lorentz violation are on the order s ~ 10000.Comment: Presented at the Fifth Meeting on CPT and Lorentz Symmetry,
Bloomington, Indiana, June 28-July 2, 201
The 3-3-1 model with A_4 flavor symmetry
We argue that the A_4 symmetry as required by three flavors of fermions may
well-embed in the SU(3)_C X SU(3)_L X U(1)_X gauge model. The new neutral
fermion singlets as introduced in a canonical seesaw mechanism can be combined
with the standard model lepton doublets to perform SU(3)_L triplets. Various
leptoscalar multiplets such as singlets, doublets, and triplets as played in
the models of A_4 are unified in single SU(3)_L antisextets. As a result,
naturally light neutrinos with various kinds of mass hierarchies are obtained
as a combination of type I and type II seesaw contributions. The observed
neutrino mixing pattern in terms of the Harrison-Perkins-Scott proposal is
obtained by enforcing of the A_4 group. The quark masses and
Cabibbo-Kobayashi-Maskawa mixing matrix are also discussed. By virtue of very
heavy antisextets the nature of the vacuum alignments of scalar fields can be
given.Comment: Version published by PR
Single Z' production at CLIC based on e^- gamma collisions
We analyze the potential of CLIC based on e- gamma collisions to search for
new gauge boson. Single Z' production at e-gamma colliders in two SU(3)_C
X SU(3)_L X U(1)_N models: the minimal model and the model with right-handed
(RH) neutrinos is studied in detail. Results show that new Z' gauge bosons can
be observed at the CLIC, and the cross sections in the model with RH neutrinos
are bigger than those in the minimal one.Comment: 11 pages, 4 figures, To appear in JET
Eimeria tenella protein trafficking: differential regulation of secretion versus surface tethering during the life cycle
Eimeria spp. are intracellular parasites that have a major impact on poultry. Effective live vaccines are available and the development of reverse genetic technologies has raised the prospect of using Eimeria spp. as recombinant vectors to express additional immunoprotective antigens. To study the ability of Eimeria to secrete foreign antigens or display them on the surface of the sporozoite, transiently transfected populations of E. tenella expressing the fluorescent protein mCherry, linked to endogenous signal peptide (SP) and glycophosphatidylinositol-anchor (GPI) sequences, were examined. The SP from microneme protein EtMIC2 (SP2) allowed efficient trafficking of mCherry to cytoplasmic vesicles and following the C-terminal addition of a GPI-anchor (from surface antigen EtSAG1) mCherry was expressed on the sporozoite surface. In stable transgenic populations, mCherry fused to SP2 was secreted into the sporocyst cavity of the oocysts and after excystation, secretion was detected in culture supernatants but not into the parasitophorous vacuole after invasion. When the GPI was incorporated, mCherry was observed on the sporozites surface and in the supernatant of invading sporozoites. The proven secretion and surface exposure of mCherry suggests that antigen fusions with SP2 and GPI of EtSAG1 may be promising candidates to examine induction of protective immunity against heterologous pathogens
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