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Abstract

The proposed compound sound sources for low-frequency noise control applications are composed of dipole sources. Their spatial radiation, which is critical in the modal field of small, closed spaces, is intended to be controlled with independent driving signals of each dipole. The need for small and efficient low-frequency elementary monopole sources led to the proposed vented sub-woofer loudspeaker design with low force factor (low-Bl) drivers. The investigated sources are set up in quadrupole configurations and measured in terms of polar near field response patterns to verify the theoretical predictions. The measurement results consist of the validation of the proposed compound sound sources on the implementation of active noise control problems in the low-frequency range. Also, their small size and modular construction make them interesting for use in other applications.
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Bibliography

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Authors and Affiliations

Marios Giouvanakis
1
Christos Sevastiadis
1
George Papanikolaou
1

  1. Department of Electrical and Computer Engineering, Aristotle University of Thessaloniki
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Abstract

Thirty four specimens of bony fishes (5 species) and four specimens of skates (2 species) were examined. Skates were infected with adult representatives of Phyllobothrium sp. (Tetraphyllidea) and Macrobothridium sp. (Diphyllidea). Bony fishes were infected with three morphological forms of tetraphyllidean cercoids (with mono- and bilocular bothridia, and bothridia undivided with hook-like projections), diphyllobothrid plerocercoids and one pseudophyllidean species, Bothriocephalus antarcticus sp.n. This species, as well as two species found in skates, seems to be endemic for the Kerguelen subregion.

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Authors and Affiliations

Anna Wojciechowska
Eva Pisano
Krzysztof Zdzitowiecki
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Abstract

In total, 8511 amphipods of 12 species caught in Admiralty Bay were examined for the presence of acanthocephalans using them as intermediate hosts. Only 27 specimens of eight species were infected (total prevalence 0.32%). Acanthellae and cystacanths of four species using fishes as either definitive or paratenic hosts were found. Normally, single parasites occurred; in one case two acanthocephalans were present in one specimen of Bovallia gigantea. This host species was the most strongly infected, with the prevalence 3.41%. Six other amphipod species were infected with the prevalence 0.08-0.66%. One of two Jassa ingens examined was also infected. Over 50% of acanthocephalans belonged to one echinorhynchid species maturing in fishes, Aspersentis megarhynchus, which occurred in five host species of four amphipod families, B. gigantea, Gondogeneia antarctica, J. ingens, Hippomedon kergueleni and Orchomenella rotundi-frons. Two polymorphid species maturing in seals, Corynosoma hamanni and C. pseudohamanni, were found in a single host species each, Prostebbingia brevicornis and Cheirimedon femoratus, respectively. Three parasite species mentioned occurred exclusively in sublittoral host species, at the depth 0-30 m. The third polymorphid species, C. bullosum, was the only species occurring in the amphipod, Waldeckia obesa, living in the deeper water (infected specimen was caught at the depth 60 m), but was found also in B. gigantea. Differences between infections of Amphipoda and fishes with echinorhynchids and polymorphids are discussed.

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Authors and Affiliations

Krzysztof Zdzitowiecki
Piotr Presler
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Abstract

One of the most serious seed-borne diseases of flax is anthracnose or seedling blight caused by Colletotrichum lini (West.) Toch. This disease affects flax seedlings, leaves, stems, and fruit bags. It causes reductions in linseed germination power, stand density, stem and linseed yield, fibre output and quality. During 1999-2001 experiments were carried out at the Lithuanian Institute ofAgriculture Upyte Experimental Station to test the efficacy of seven fungicides used for seed dressing against flax anthracnose and other seedborne diseases. Experimental findings indicated that 19.0% to 34.0% of flax seeds were annually infected with C. lini (West.) Toch. causing flax anthracnose. As the disease can spread through the soil, on control plots sown with untreated with fungicides seeds 33.0% to 79.5% of seedlings showed symptoms of anthracnose. Seed treatment with Sportak 45 EC used at the dose 0.8 l f1 and Maxim Star 025 FS used at the dose 1.51 t-1 gave the best control of seedling blight causal agents. Their biological efficacy was as follows: against seed anthracnose 97.3% and 96.3%, at seedling stage, 76.5% and 76.3%, at 'fir-tree' stage - 67.8% and 60.4%. Biological efficacy of the other seed treaters was lower. The highest straw yield increases resulted from seed treatment with the Maxim Star 025 FS and Sportak 45 EC - 0.5 and 0.3 t ha" or 11.0% and 6.2%, respectively. The effect of fungicides used for seed treatment on linseed yield was similar. Maxim Star 025 FS increased the yield on average by 22.1%, and Sportak 45 EC and Premis 25 FS by 13. 7% and 13.3%. The other fungicides, except for Raxil 2 WS and Rovral FLO, also had a positive effect on flax straw and linseed yield, however, in all experimental years the increases were not higher than the least significant difference.
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Authors and Affiliations

Elvyra Gruzdeviene
Zenonas Dabkevicius
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Abstract

Messina in the stories of Polish travelers over the course of centuries: the double face of the city – The article presents Messina’s ‘verbal postcards’ left by Polish participants in the Grand Tour and travelers who visited Sicily in later times. Travelers whose accounts are widely known, such as Anonymous (1595), Michał Borch, Julian Ursyn Niemcewicz, Chrystian Kamsetzer (XVIII c.), Zygmunt Krasiński (nineteenth century), but also less well-known ones such as writer Zofia Sokołowska, arriving in Sicily in the tragic year of the earthquake (1908), left descriptions from their stays in Messina about the emotional charge they felt, one closely related to the historical moment in which they arrived on the island. This will therefore be a thorough analysis of a fragment of the Sicilian journey concerning Messina left by some Polish travelers, taking into account their professions, areas of interest and the period in which they were in Sicily.

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Authors and Affiliations

Anna Tylusińska-Kowalska

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