1,079 research outputs found

    REACTIVITY OF CHLOROPHYLL a/b-PROTEINS AND MICELLAR TRITON X-100 COMPLEXES OF CHLOROPHYLLS a OR b WITH BOROHYDRIDE

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    The reaction of several plant chlorophyll-protein complexes with NaBH4 has been studied by absorption spectroscopy. In all the complexes studied, chlorophyll b is more reactive than Chi a, due to preferential reaction of its formyl substituent at C-7. The complexes also show large variations in reactivity towards NaBH4 and the order of reactivity is: LHCI > PSII complex > LHCII > PSI > P700 (investigated as a component of PSI). Differential pools of the same type of chlorophyll have been observed in several complexes. Parallel work was undertaken on the reactivity of micellar complexes of chlorophyll a and of chlorophyll b with NaBH4 to study the effect of aggregation state on this reactivity. In these complexes, both chlorophyll a and b show large variations in reactivity in the order monomer > oligomer > polymer with chlorophyll b generally being more reactive than chlorophyll a. It is concluded that aggregation decreases the reactivity of chlorophylls towards NaBH4 in vitro, and may similarly decrease reactivity in naturally-occurring chlorophyll-protein complexes

    Nitrogen Budgets on a Pasture under Combined Utilization of Grazing and Cutting

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    Nitrogen budgets on a pasture being utilized for both grazing and cutting were investigated. A pasture containing tallfescue, orchard grass and white clover was divided into two areas: initially grazed (IA, 0.41ha) and grazed after cutting for hay (BA, 0.49ha). A herd of 4-5 cattle (heifers or steers of Japanese Black or Holstein) grazed at IA from 22 Apr. to 2 Jul. and grazed at both IA and BA from 3 Jul. to 21 Oct. 1999. The amount of N grazed from IA was 3 times higher than the sum of N of grazed herbage and harvested hay from BA. The amount of N inflow to soil as fertilizer or animal excreta seemed to relate to the difference in herbage production between IA and BA. The value of N surplus for the whole pasture was very similar to the value of the difference between inflow to soil and the sum of grazed herbage and harvested hay. N surplus in the pasture seemed to relate closely to soil N balance

    Search for the decay KL0→3γK_L^0 \rightarrow 3\gamma

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    We performed a search for the decay KL0→3γK_L^0 \rightarrow 3\gamma with the E391a detector at KEK. In the data accumulated in 2005, no event was observed in the signal region. Based on the assumption of KL0→3γK_L^0 \rightarrow 3\gamma proceeding via parity-violation, we obtained the single event sensitivity to be (3.23±0.14)×10−8(3.23\pm0.14)\times10^{-8}, and set an upper limit on the branching ratio to be 7.4×10−87.4\times10^{-8} at the 90% confidence level. This is a factor of 3.2 improvement compared to the previous results. The results of KL0→3γK_L^0 \rightarrow 3\gamma proceeding via parity-conservation were also presented in this paper

    Experimental study of the decay KL0→π0ννˉK_L^0\to\pi^0\nu\bar{\nu}

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    The first dedicated search for the rare neutral-kaon decay KL0→π0ννˉK_L^0\to\pi^0\nu\bar{\nu} has been carried out in the E391a experiment at the KEK 12-GeV proton synchrotron. The final upper limit of 2.6 ×10−8\times 10^{-8} at the 90% confidence level was set on the branching ratio for the decay.Comment: 23 pages, 27 figures, accepted for publication as a regular article in Physical Review
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