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  • Author or Editor: P. Horváth x
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Until recently the etiology of bovine spongiform encephalopathy (BSE) was considered uniform. The infectious agent was thought to be a single strain of prion (posttranslationally altered form of normal prion protein: PrPSc) retaining its biochemical and biological characteristics during interspecies transmission. However, alternate PrPSc signatures through large-scale screening have recently been detected. In addition, genetic alterations governing susceptibility to prion infection and a mutation (E211K) capable of eliciting spontaneous BSE have been demonstrated. Thus, the spectrum of BSEs have broadened and three PrPSc variants (BSE-C, BSE-H and BSE-L) are now defined. Moreover, a new condition resembling BSE, idiopathic brainstem neuronal chromatolysis (IBNC), has been described that may also turn out to be a prion disease. Since one of the new BSE variants, L-type BSE, proved highly pathogenic detection and further characterization of the new conditions are essential.

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Authors provide a 6-year study about aspects of development of Cameraria ohridella and its parasitoids in different leaf types of horse-chestnut trees. Investigations were carried out near Hédervár, North-West Hungary between 1999 and 2004.It was ascertained that in large leaves at low foliage levels as well as in large leaves exposed to direct sunlight developed more moths than in other leaf types of equal quantity (i.e. equal number of leaflets). On the other hand, there were not considerable differences between shaded and sun-exposed leaves in this regard if their quantity is measured in grams. Moreover, comparing the numbers of hatched moths per unit leaf weight, the values for minute leaves were the highest. The differences were explained on the basis of diverse microclimatic conditions in the mines, height preference of the moth or variations in dry weights per unit leaf area.Parasitism of Cameraria ohridella showed significant yearly differences between canopy levels and a tendency of changes during the years. Parasitism was higher in shaded than in sun-exposed leaves. Lowest values were found in minute leaves among all leaf types investigated what was explained with a presumed foraging behaviour of the parasitoids.Structure and species constitution of the parasitoid community and its changes in time are discussed in different leaf types. Temporal changes of several characteristics found in different leaf types refer to an adaptation process of the horse-chestnut leafminer.

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The horse-chestnut leafminer is a new pest which was established in North-West Hungary ca. 10 years prior to these investigations. Due to the very limited time, there are relatively few studies on the parasitoid community of the moth and its connection with the leafminer host. Authors used twig-isolators to find out which larval/pupal instars are mostly parasitized and by which chalcidoid species. They also made an attempt to calculate density curves of different developmental stages of the moth and to compare them with flight curves of the parasitoids. Experiences indicated that 4-week-old larval (pupal) instars were parasitized to the highest degree. The most frequent parasitoids were Pediobius saulius and Pnigalio agraules . Statements about a poor synchronization between moth and parasitoids were confirmed but possibility of a shift in swarming times on location was suggested. Different methods to calculate rate of parasitism were compared and evaluated.

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Abstract

In a Freud-type weighted (w) space, introducing another weight (v) with infinitely many roots, we give a complete and minimal system with respect to vw, by deleting infinitely many elements from the original orthonormal system with respect to w. The construction of the conjugate system implies an interpolation problem at infinitely many nodes. Besides the existence, we give some convergence properties of the solution.

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A new equipment based on the inverse-die method

Application of a twin-calorimeter in agricultural industry I

Journal of Thermal Analysis and Calorimetry
Authors: J. Horváth, P. Prommer and P. Marik-Korda

An automated twin-calorimeter has been developed for the analysis of relatively small sample series which is suitable for the simple and fast analysis of fertilizers. The apparatus was given the name AGROTHERM

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The aim of our study was to investigate the susceptibility of some Chenopodium species (Chenopodium album, C. glaucum, C. berlandieri, C. ugandae) to six viruses (Alfalfa mosaic virus, Cucumber mosaic virus, Obuda pepper virus, Potato virus Y, Sowbane mosaic virus, Zucchini yellow mosaic virus). Fourteen plants of each species were mechanically inoculated and virus susceptibility was evaluated on the basis of symptoms and back inoculation. A series of new host-virus relations were determined.

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In this review results are summarized regarding the effect of virus infection on the physiological processes of weeds. Through several host-virus model relations the biomass and seed production, seed viability and germination, nutrient uptake, drought-resistance and photosynthetic pigment content of healthy and virus infected plants were compared. Because of their broad host range and high genetic variability viruses cannot be used for biological weed control. It was concluded that viruses unfavourably can influence physiological processes of weeds. Therefore, they may contribute indirectly to the reduction of competitive ability and population of weeds.

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Periodica Mathematica Hungarica
Authors: P. Erdős, R. Farzan and Gy. Horváth
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