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  • Author or Editor: G. Bán x
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We investigated alfalfa and stinging nettle from the point of view of their potential to supply natural enemies of pests for protecting greenhouse cultures. We carried out a three year long study based on sweepnetting. The most frequent predatory insect was Orius niger (Wolff) in alfalfa and nettle. This species among others has an important potential in the biological control of thrips. Among ladybugs, the most important species in alfalfa and nettle were Propylea quatuordecimpunctata (Linnaeus), Coccinella septempunctata Linnaeus and Hippodamia variegata (Goeze), which consume significant amounts of aphids. The most frequent spider family in alfalfa and nettle was Thomisidae and Philodromidae. The dynamics of their prey composition suggests that these taxa present a significant suppressive force on pests. The predator thrips Aeolothrips intermedius Bagnall that feeds on phytophagous thrips, mites and other soft-bodied arthropods was also significant in the arthropod assemblage of alfalfa. Our three-year investigation showed that the abundance and the species richness of the natural enemies of greenhouse crops are suitably high in both alfalfa and nettle stands. The number of generalist predators, natural enemies of pests, the most versatile tools of pest management reached its peak between mid-May to late June in nettle whereas due to mowing, the highest values for alfalfa were recorded from June to mid-August.

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Recent years of studies have suggested that the common crab spider (Xysticus kochi) has a great potential against the western flower thrips (Frankliniella occidentalis) . The efficiency of applying a single predator against a pest however, is made uncertain by many different factors. Using a mixture of predators on the other hand, can overcome the difficulties of using a single-species agent, since different predators have different environmental demands and preying habits. Our experiments involved releasing a non-selected assemblage of arthropods, collected by sweep-net in alfalfa and stinging nettle, into greenhouse pepper stands. Interestingly, while there were twice as much thrips in the experimental greenhouses than in the control (mainly conventional) ones, crop yields were similar. The ratio of predators-preys in experimental greenhouses was not different from that in the control greenhouses, too. Probably the release of predators and lack of chemical treatments in experimental stands resulted in a 43% increase in the amount of Orius species. In search of a cost-effective, environment-friendly pest management method, the application of a mass-collected, non-selected assemblages of arthropods has a definite potential. Further investigations are needed to increase the efficiency and to monitor the potential drawbacks of this method.

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Effects of habitat characteristics and climatic factors on the occurrence of reed pathogens were investigated in a four-year survey. While diseases caused by Puccinia magnusiana, Polythrinciopsis phragmitis and Stago­no­spora sp. started to increase as early as in August, the other species caused severe infection in September (Deightoniella arundinacea, Puccinia phrag­mitis) or even later in the vegetation period (Deightoniella roumeguerei). For the distribution of some fungal pathogens (Puccinia phragmitis, Deighto­niella arundinacea, D. roumeguerei and Stagonospora sp.) weather conditions (especially precipitation) were profound, while the occurrence of others (Puccinia magnusiana and Polythrinciopsis phragmitis) depend­ed more on the characteristics of reed stands.

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Western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) is one of the most important pests of greenhouse pepper in Hungary. It has a hidden lifestyle, a short generation interval and a high reproductive rate. Due to these characteristics it is difficult to obtain an effective, environment-friendly and harmless control of the pest. Previous studies have shown that under caged plant conditions, the common crab spider, Xysticus kochi (Thorell) (Araneae: Thomisidae) is effective against western flower thrips. In this study, we examined some of the technological questions of the use of spider larvae.We investigated the necessary amount and number of applications of spider larvae under caged plant conditions. The efficiency of spiders at the whole greenhouse level was also studied. While the ratio of damaged surface of peppers treated with X . kochi was significantly lower than that of non-treated plants, increasing the amount of spider larvae did not improve the effectiveness of thrips control. Although whole greenhouse experiences showed a similar, significant decrease in the rate of damaged surface in the case of peppers treated with spider larvae, when compared to untreated control; the efficiency of spiders remained below the level of economic acceptance.

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Summary Oxide materials belonging to the Sn-Ce-O system are very interesting due to their use as solid electrolytes in fuel cells, catalysts, sensors and photoanodes in solar cells. The aim of the present work is to investigate the thermal behaviour of some tin and cerium salt mixtures. Mixtures with different representative Sn:Ce atomic ratio were prepared by classical ceramic method using SnC2O4, Ce(SO4)2·4H2O and (NH4)2Ce(NO3)6 as starting compounds. The samples were investigated by means of TG/DTA methods in flowing and static air atmosphere. SnO2 and/or CeO2 were identified by X-ray diffraction and IR spectroscopy in the final decomposition products, depending on the initial composition of the both series. A different crystallinity degree of the solid products was observed depending on the Ce precursor.

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Abstract  

Composition and structure of crystals of unknown origin, crystallizing spontaneously from ethylenediamine on standing, has been determined by elemental analysis, FTIR, 1H and 13C NMR spectroscopy and X-ray diffraction. The crystal with molecular formula C6H14N4 has been found to be a highly symmetric saturated imino compound with double-ring structure, and unambiguously identified as trans-1,4,5,8-tetraazodecalin by 1H NMR and powder X-ray diffraction based on both its specific AA'BB' spin coupling system and simulated XRD pattern calculated from available data of previous single crystal structure determination, respectively. Simultaneous TG/DTA measurement shows one-step degradation of this compound. The volatile decomposition products have been followed by both TG/DTA-MS and TG-FTIR. Group of the largest fragments (m/z=80, 81 and 82) observed by TG/DTA-MS corresponds to an aromatic 1,4-diazine (pyrazine). In the EGA-FTIR spectrum of released gaseous species measured at the highest evolution rate by TG-FTIR, ethylenediamine can be identified as another decomposition product.

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Abstract  

Thermal stability and structural features of three newly synthesized 1:1 lattice compounds of theophylline (th) with ethylenediamine carbamate (enCO 2), 1,10-phenanthroline (phen), and 5-sulfosalicylic acid (sa-5-SO 3 H) have been studied in comparison with those of the theophylline compounds with ethanolamine (ea) and salicylic acid (sa). Simultaneous TG-DTA measurements, FTIR spectroscopy and X-ray diffraction have been carried out to get information on the various structural units of these solid inclusions, especially on the actual form (molecule, anion or cation) of theophylline moieties built in. Theophyllinate and theophyllinium ions have been found in the ethanolammonium-theophyllinate (1:1) (1, eaH + th -) and the theophyllinium salicylic acid 5-sulfonate monohydrate (1:1:1), (5, thH + saSO 3 H 2 O), respectively. Whilst the 1:1 complexes with 1,10-phenanthroline (2, thphen), ethylenediamine carbamate (3, thenCO 2), and salicylic acid (4, thsa) contain neutral theophylline moieties associated with H-bonds. In compound (3) the zwitterion of N-(2-ammonium-ethyl)carbamate (NH3 +-CH2-CH2-NH-CO- 2) is present.

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Abstract  

Neutron activation analysis (NAA) remains an excellent technique to introduce undergraduate students to nuclear science and engineering coming from different academic areas. The NAA methods encompass an appreciation of basic reactor engineering concepts, radiation safety, nuclear instrumentation and data analysis. At the Nuclear Engineering Teaching Lab at the University of Texas at Austin we have continued to provide opportunities through outreach programs to Huston-Tillotson University in Austin and Florida Memorial University in Miami Gardens, both Historically Black Colleges and Universities, and Southwestern University in Georgetown, Texas. Furthermore, in the past four years we have established a strong educational collaboration with the École Nationale Supérieure d’Ingénieurs de Caen (ENSICAEN), France. Undergraduate students at ENSICAEN are required to have an internship outside of France. While many of the students stay in neighboring European countries others have chosen the United States. The cornerstone of these programs is to secure a relationship with each institution through clear educational and research objectives and goals.

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