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  • Author or Editor: K. Kovács x
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We try to characterize the number of di .erent elements in A = {a 1, a 2 a n}j n such that {a 1 +a 2, a 2 +a 3a n +a 1}=Z n or {a 2 -a 1, a 3 -a 2a 1 -a n}=Z n .Partial results are proved.E.g.,in the second case for odd n all the integers in ((3 n +1)/4, n) occur.

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Growth characteristics, such as basal stem diameter, total length of wooded branches and root/shoot ratios in different ecological populations of Fumana procumbenswere studied in the perennial open sand grassland Festucetum vaginataeunder different climatic conditions in Hungary. The age of individual plants was determined by counting the annual rings in the basal section of stems. Basal stem diameters and their average yearly increment as well as the total length of wooded branches with individuals of the same age were significantly higher under wet conditions. The close relation of basal stem diameters and branch length with age could be described by linear regression both under wet and dry conditions. There was no significant differences in the root/shoot ratios between the dry and wet sites. Having established a reliable relation between basal stem diameter and age of Fumanaindividuals, authors developed a simple, quick and non-destructive field method for age determination of Fumana.

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The compounds of interest in the present study were the natural compounds rutin and quercetin, which are strong antioxidants and have beneficial effects on human health (Myake & Shibamoto, 1997). They are present in everyday foods and beverages and in this way they are used as an integral part of human diet. Therefore, it seemed interesting to investigate the influence of these valuable natural compounds on corrosion processes of aluminium, an ambalage material often used in food industry (Jovanovic et al., 1994). All the investigations were performed in 3% solution of sodium chloride, in aqueous rutin and quercetin solutions as well as in rutin and quercetin solutions in 3% sodium chloride solution. Concentrations of rutin and quercetin solutions used ranged from 10-2 to 10-5 mol dm-3, and investigations involved electrochemical methods. The results obtained showed that rutin and quercetin previously dissolved in 0.1 M NaOH and added to the 3% sodium chloride solution at concentrations of 10-4 and 10-5 mol dm-3 acted as aluminium corrosion inhibitors, while at higher concentrations (10-2 and 10-3 mol dm-3) their effects were opposite. The efficiency of the corrosion inhibition of aluminium by rutin and quercetin solutions was the result of forming protective film on the metal surface. Therefore, the diluted rutin and quercetin solutions could be used as corrosion inhibitors of aluminium.

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A tanulmány - Arthur Jensen munkásságát középpontba helyezve - áttekinti az IQ-vita elmúlt 30 évének történetét. Bemutatja az általános intelligencia klasszikus, örökléselvű koncepcióját, valamint az azzal szembeni legfontosabb kihívásokat. Külön hangsúlyozza a koncepció társadalmi vonatkozásait és jelentőségét, valamint a biológiai orientációjú intelligenciakutatás helyét a pszichológiában. Végül bemutatja a közelmúltban újra fellángoló IQ-vitában elhangzott fontosabb érveket.

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