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Circumferential variation in heartwood in stands of black locust (Robinia pseudoacacia L.)

Klisz M, Wojda T., Jastrzębowski S., Ukalska J.

Drewno : prace naukowe, doniesienia, komunikaty

2015

vol. 58, nr 195

31--44

Within the framework of work on the anatomical structure and durability features of wood, as well as analyses of radial growth, a preliminary analysis was carried out in regard to variation in the heartwood within Black locust trees. The research was carried out in three stands of straight-stemmed trees in western Poland. The variation displayed by the heartwood around its circumference and the eccentricity of the trunks was characterised with reference to: the heartwood radial index (HRI), the cross-sectional shape factor for heartwood (CSsf) and the pith eccentricity index (PEcc). The results confirmed a relationship between the degree of variation around the circumference of the heartwood and the mean age of the stands, while at the same time making clear the high level of differentiation in radial variation at the level of the individual tree. The findings suggest that the fertility of the habitat does not exert much of an influence on the generation of heartwood in Black locust trees. No statistically significant relationship was obtained when the circumferential variation of the heartwood was set against the total height or diameter at breast-height. Only in the case of crown length, and then only at the Wołów site, was there a moderate negative correlation with the coefficients of circumferential variation.

Comparative analysis of database access technology

Barczak A., Zacharczuk D., Jastrzębowski S.

Studia Informatica : systems and information technology

2009

Vol. 1(12)

15--31

The paper’s subject is comparative analysis of database access technologies. It presents the evolution of the discussed technologies, which are divided into the following categories: single-platform and multi-platform technologies. Sample programs showing the use of programming interfaces, used for initiating and establishing connections with databases and performing simple operations on them. A database diagram, which was used for measuring efficiency of selected technologies as well as testing plan and concept, system and hardware parameters, tested queries and the program skeleton that was used for measuring the efficiency of selected technologies, were presented. The results were grouped according to 4 query types and 3 operating systems. A description was attached to each graph. Conclusions were provided for query tests for each of the operating systems. Finally, the most efficient technologies were discussed, potential causes of increase or decrease in efficiency were presented, and the results were summarized.