21 research outputs found

    Azimuthal correlation between the (pl,pXb)(\vec{p}_l,\vec{p}_{X_b}) and (pl,Pt)(\vec{p}_l,\vec{P}_t) planes in the semileptonic rest frame decay of a polarized top quark: An O(αs)O(\alpha_s) effect

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    The azimuthal correlation between the planes formed by the vectors (p,pXb)(\vec{p}_\ell,\vec{p}_{X_b}) and (p,Pt)(\vec{p}_\ell,\vec{P}_t) in the semileptonic rest frame decay of a polarized top quark t()Xb+l++νt(\uparrow) \to X_b + l^+ + \nu_\ell belongs to a class of polarization observables involving the top quark which vanish at the Born term level in the standard model. We determine the next--to--leading order QCD corrections to the afore-mentioned azimuthal correlation and compare the result to the corresponding contribution of a non--standard--model right--chiral quark current.Comment: latex, 12 pages with 2 figures in the text, typos removed,comment and references added, replaced with published versio

    Supercomplex-Associated Cox26 Protein Binds to Cytochrome \u3cem\u3ec\u3c/em\u3e Oxidase

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    Here we identified a hydrophobic 6.4 kDa protein, Cox26, as a novel component of yeast mitochondrial supercomplex comprising respiratory complexes III and IV. Multi-dimensional native and denaturing electrophoretic techniques were used to identify proteins interacting with Cox26. The majority of the Cox26 protein was found non-covalently bound to the complex IV moiety of the III–IV supercomplexes. A population of Cox26 was observed to exist in a disulfide bond partnership with the Cox2 subunit of complex IV. No pronounced growth phenotype for Cox26 deficiency was observed, indicating that Cox26 may not play a critical role in the COX enzymology, and we speculate that Cox26 may serve to regulate or support the Cox2 protein. Respiratory supercomplexes are assembled in the absence of the Cox26 protein, however their pattern slightly differs to the wild type III–IV supercomplex appearance. The catalytic activities of complexes III and IV were observed to be normal and respiration was comparable to wild type as long as cells were cultivated under normal growth conditions. Stress conditions, such as elevated temperatures resulted in mild decrease of respiration in non-fermentative media when the Cox26 protein was absent

    O(αs) O(\alpha_s) corrections to polarized top decay into a charged Higgs t()H++b t(\uparrow) \to H^+ + b

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    We calculate the O(αs) O(\alpha_s) radiative corrections to polarized top quark decay into a charged Higgs boson and a massive bottom quark in two variants of the two-Higgs-doublet model. The radiative corrections to the polarization asymmetry of the decay may become as large as 25 25 % . We provide analytical formulae for the unpolarized and polarized rates for mb0 m_b \neq 0 and for mb=0 m_b = 0 . For mb=0 m_b = 0 our closed-form expressions for the unpolarized and polarized rates become rather compact.Comment: 24 pages, 5 figures in the text, content modified, comments added, appendices added, references updated, replaced with published versio

    The use of Arabidopsis thaliana model system for testing oil palm promoter: case study on oil palm MT3-A promote

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    A previous study on transient expression of oil palm tissues has shown that the oil palm metallothionein-like type 3 (MT3-A) gene promoter is specifically expressed in the mesocarp and not in other tissues. This study was conducted to determine whether or not Arabidopsis can be used as a model system to study oil palm promoter. Functional characterisation of the oil palm MT3-A promoter was performed using promoter::GUS fusion analysis in transgenic Arabidopsis. The localisation of β-glucuronidase (GUS) expression in several different tissues of transgenic Arabidopsis homozygous lines driven by the oil palm MT3-A promoter was determined. Histochemical GUS analysis in transgenic Arabidopsis revealed the highest expression in the cotyledon and hypocotyls as well as at the early stage of plant development and gradually decreased as the plant grew. Lower expression was detected in organs of mature plant and no expression was observed in reproductive tissues. This observation may suggest that MT3-A promoter might be involved during early stage of plant development. Since we use Arabidopsis which is neither a fruit nor mesocarp plant to check mesocarp-specific promoter it might not give a faithful pattern of expression but it may be suited to study oil palm specific promoter derived from other tissues
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