616 research outputs found
Strong-coupling Analysis of Parity Phase Structure in Staggered-Wilson Fermions
We study strong-coupling lattice QCD with staggered-Wilson fermions, with
emphasis on discrete symmetries and possibility of their spontaneous breaking.
We perform hopping parameter expansion and effective potential analyses in the
strong-coupling limit. From gap equations we find nonzero pion condensate in
some range of a mass parameter, which indicates existence of the parity-broken
phase in lattice QCD with staggered-Wilson fermions. We also find massless
pions and PCAC relations around second-order phase boundary. These results
suggest that we can take a chiral limit by tuning a mass parameter in lattice
QCD with staggered-Wilson fermions as with the Wilson fermion.Comment: 37 pages, 9 figure
Index Theorem and Overlap Formalism with Naive and Minimally Doubled Fermions
We present a theoretical foundation for the Index theorem in naive and
minimally doubled lattice fermions by studying the spectral flow of a Hermitean
version of Dirac operators. We utilize the point splitting method to implement
flavored mass terms, which play an important role in constructing proper
Hermitean operators. We show the spectral flow correctly detects the index of
the would-be zero modes which is determined by gauge field topology. Using the
flavored mass terms, we present new types of overlap fermions from the naive
fermion kernels, with a number of flavors that depends on the choice of the
mass terms. We succeed to obtain a single-flavor naive overlap fermion which
maintains hypercubic symmetry.Comment: 27 pages, 17 figures; references added, version accepted in JHE
Change in Localization of Alkaline Phosphatase and Mannosidase II by Colchicine Treatment of Primary Cultures of Fetal Rat Hepatocytes
We examined the changes in localization of alkaline phosphatase (ALP) and mannosidase II (man II), a Golgi marker, after colchicine treatment of primary cultures of fetal rat hepatocytes, using double immunofluorescence staining and confocal laser microscopy. In hepatocytes cultured in basal medium, ALP was localized in the perinuclear cytoplasm, and man II was observed in the Golgi region of the cytoplasm. When hepatocytes were cultured in dexamethasone-supplemented medium, ALP was also localized in the plasma membrane surrounding the bile canaliculus-like structure that was formed between adjacent cells. In hepatocytes cultured in the same medium containing colchicine, the structure of microtubules in the cytoplasm was lost, man II exhibited granular distribution scattering throughout the cytoplasm, and ALP was localized in coarse granular sites of the cytoplasm. However, ALP was not colocalized at the same sites as man II. The present study indicated that colchicine inhibits the dexamethasone-promoted translocation of ALP to the plasma membrane surrounding the bile canaliculus-like structure in primary cultures of fetal rat hepatocytes by disassembling microtubules and discomposing the Golgi complex
The Conformal Transformation in General Single Field Inflation with Non-Minimal Coupling
The method of a conformal transformation is applied to a general class of
single field inflation models with non-minimal coupling to gravity and
non-standard kinetic terms, in order to reduce the cosmological perturbative
calculation to the conventional minimal coupling case to all orders in
perturbation theory. Our analysis is made simple by the fact that all
perturbation variables in the comoving gauge are conformally invariant to all
orders. The structure of the vacuum, on which cosmological correlation
functions are evaluated, is also discussed. We show how quantization in the
Jordan frame for non-minimally coupled inflation models can be equivalently
implemented in the Einstein frame. It is thereafter argued that the general
N-point cosmological correlation functions (of the curvature perturbation) are
independent of the conformal frame.Comment: 15 pages, no figure, references adde
Ecto-5ā-nucleotidase: Structure function relationships
Ecto-5ā-nucleotidase (ecto-5ā-NT) is attached via a GPI anchor to the extracellular membrane, where it hydrolyses AMP to adenosine and phosphate. Related 5ā-nucleotidases exist in bacteria, where they are exported into the periplasmic space. X-ray structures of the 5ā-nucleotidase from E. coli showed that the enzyme consists of two domains. The N-terminal domain coordinates two catalytic divalent metal ions, whereas the C-terminal domain provides the substrate specificity pocket for the nucleotides. Thus, the substrate binds at the interface of the two domains. Here, the currently available structural information on ecto-5āNT is reviewed in relation to the catalytic properties and enzyme function
Mechanisms of organelle division and inheritance and their implications regarding the origin of eukaryotic cells
Mitochondria and plastids have their own DNAs and are regarded as descendants of endosymbiotic prokaryotes. Organellar DNAs are not naked in vivo but are associated with basic proteins to form DNA-protein complexes (called organelle nuclei). The concept of organelle nuclei provides a new approach to explain the origin, division, and inheritance of organelles. Organelles divide using organelle division rings (machineries) after organelle-nuclear division. Organelle division machineries are a chimera of the FtsZ (filamentous temperature sensitive Z) ring of bacterial origin and the eukaryotic mechanochemical dynamin ring. Thus, organelle division machineries contain a key to solve the origin of organelles (eukaryotes). The maternal inheritance of organelles developed during sexual reproduction and it is also probably intimately related to the origin of organelles. The aims of this review are to describe the strategies used to reveal the dynamics of organelle division machineries, and the significance of the division machineries and maternal inheritance in the origin and evolution of eukaryotes
- ā¦