3,759 research outputs found

    A comparison of an ATPase from the archaebacterium Halobacterium saccharovorum with the F1 moiety from the Escherichia coli ATP Synthase

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    A purified ATPase associated with membranes from Halobacterium saccharovorum was compared with the F sub 1 moiety from the Escherichia coli ATP Synthase. The halobacterial enzyme was composed of two major (I and II) and two minor subunits (III and IV), whose molecular masses were 87 kDa, 60 kDa, 29 kDa, and 20 kDa, respectively. The isoelectric points of these subunits ranged from 4.1 to 4.8, which in the case of the subunits I and II was consistent with the presence of an excess of acidic amino acids (20 to 22 Mol percent). Peptide mapping of sodium dodecylsulfate-denatured subunits I and II showed no relationship between the primary structures of the individual halobacterial subunits or similarities to the subunits of the F sub 1 ATPase (EC 3.6.1.34) from E. coli. Trypsin inactivation of the halobacterial ATPase was accompanied by the partial degradation of the major subunits. This observation, taken in conjunction with molecular masses of the subunits and the native enzyme, was consistent with the previously proposed stoichiometry of 2:2:1:1. These results suggest that H. saccharovorum, and possibly, Halobacteria in general, possess an ATPase which is unlike the ubiquitous F sub o F sub 1 - ATP Synthase

    A sharp interpolation between the H\"older and Gaussian Young inequalities

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    We prove a very general sharp inequality of the H\"older--Young--type for functions defined on infinite dimensional Gaussian spaces. We begin by considering a family of commutative products for functions which interpolates between the point--wise and Wick products; this family arises naturally in the context of stochastic differential equations, through Wong--Zakai--type approximation theorems, and plays a key role in some generalizations of the Beckner--type Poincar\'e inequality. We then obtain a crucial integral representation for that family of products which is employed, together with a generalization of the classic Young inequality due to Lieb, to prove our main theorem. We stress that our main inequality contains as particular cases the H\"older inequality and Nelson's hyper-contractive estimate, thus providing a unified framework for two fundamental results of the Gaussian analysis

    The Marangoni effect and translation of free non-deformable drops

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    A model is presented for flow caused by interface tension gradients, the so called Marangoni effect, on a free, nondeformable drop. A free drop, initially at rest, undergoes a translation motion upon the action of surface flow. The experiments carried out by injecting a drop with surfactants, which induce an interface tension gradient, are in good agreement with the theoretical model proposed

    PAC commutators and the R-transform

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    Discretised Non-Linear Filtering for Dynamic Latent Variable Models: with Application to Stochastic Volatility

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    Filtering techniques are often applied to the estimation of dynamic latent variable models. However, these techniques are often based on a set assumptions which restrict models to be specified in a linear state-space form. Numerical filtering techniques have been propsed that avoid invoking such restrictive assumptions, thus permitting a wider class of latent variable models to be considered. This paper proposes an accurate yet computationally efficient numerical filtering algorithm (based on a discretisation of the state space) for estimating the general class of dynamic latent variable models. The empirical performance of this algorithm is considered within the context of the stochastic volatility model. It is found that the proposed algorithm outperforms a number of accepted procedures in terms of volatility forecastiNon-linear filtering, latent variable models, stochastic volatility, volatilitry forecasting

    MONITORING THE ATTACK PRODUCED BY THE SPECIES CAMERARIA OHRIDELLA DESCHKA-DIMIĆ IN CRAIOVA AREA

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    Cameraria ohridella Deschka-Dimić is an invasive, monophagous species, extremely dangerous for the ornamental chestnut trees.Following the observations we made, it can be concluded that the southern exhibition is preferred by the larvae of the species Cameraria ohridella Deschka-Dimić, so for observation made in July 2019 the values were 3.6 mines/leaf and 8.7 mines/leaf in August, and this year it was 3.9 mines/leaf for July, reaching 8.9 mines/leaf in August, an indicator that increased rapidly over the time between the two observations and  followed by the leaves with eastern exposure and western.We also noticed that the lowest values of the average number of mines/leaf/foliole were reached on the leaves with northern exposure
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