Number of hairs on abaxial leaf surface of 13 apple cultivars differed significantly. The most hairs per 1 cm² on abaxial surface were on cvs. Lodel (2,578.3) and Jonafree (2,462.2). Leaves of cultivars Antonówka and Novamac had the least number of hairs (1,054.4; 1,285.7; respectively). Correlation between number of hairs on abaxial leaf surface of investigated apple cultivars and Tetranychus urticae (Koch) female fecundity decreased during 10 first days of their lives. Along with increased number of hairs, the fecundity of this species declined.

The paper is a comment to the published in this yearbook of TEKA KOMISJI URBANISTYKI I ARCHITEKTURY memorial text „Żórawski’s School” by Janusz Ballenstedt written 50 years ago. The author confirms the actuality of Ballenstedt’s remarks on professor architect Juliusz Żórawski (1898–1967) as teacher of architectural design, and widens the argumentation quoting Żórawski’s proposal of the notion: “employment of space”, suggested by Żórawski for designers on the example of cinema waiting hall. Citation from the “Felieton” by Żórawski allows the reader better to understand the specificity of experiment which the architect performed when designing the apartment house at Aleja Przyjaciół in Warsaw, focused on providing comfort for the inhabitants.

In this article, a 3D printed rectangular dielectric resonator antenna which is capable of polarization reconfiguration has been designed. Dielectric resonator is composed of environment friendly and biodegradable material, which is Polylactic Acid. In the proposed model, the polarization can be switch from a linear to a circular by changing the state of a switch, electonically. The antenna switch between two different polarizations: Linear polarization during OFF STATE and Lefthand circular polarization during ON STATE. The proposed 3D printed dielectric resonator antenna is designed to operate in Cband of microwave spectrum, with a broad effective bandwidth (overlapped impedance bandwidths of both states) of 14.542% with centre frequency at 5.845GHz and peak gain 5.5dBi. Further, validated simulated results with experiment and both results are in good agreement.