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A b s t r a c t Offering more floral resources for urban bees can be achieved by growing ornamental bee plants. The aim of the present study was to evaluate selected Asteraceae (Calendula officinalis 'Persimmon Beauty' and 'Santana', Centaurea macrocephala, Cosmos sulphureus, Dahlia pinnata, Tagetes patula, Tithonia rotundifolia, and Zinnia elegans) as pollen sources for pollinators. Under urban conditions in Lublin, SE Poland, the investigated plants flowered from late June to the end of October. The mass of pollen produced in florets and capitula was found to be species-related. The highest pollen amounts per 10 florets (10.1 mg) as well as per capitulum (249.7 mg) were found for C. macrocephala. The mass of pollen yielded by a single plant depended on both the pollen mass delivered per disk florets and the proportion of disk florets in capitulum, and the flowering abundance of the plants. A single plant of D. pinnata and a single plant of T. rotundifolia each produced the largest pollen mass. Mean pollen yield per 1m 2 of a plot ranged from 6.2 g (Z. elegans) to 60.7 g (D. pinnata). Pollen grains are tricolporate, with echinate exine, medium or small in size. They can be categorised as oblatespherical, spherical, and prolatespherical. The principal visitors to C. macrocephala, C. sulphureus, and C. officinalis were honey bees, whereas bumble bees dominated on T. rotundifolia and D. pinnata. A magnet plant for butterflies was Z. elegans. Among the investigated species, D. pinnata, C. macrocephala, and T. rotundifolia were found to be the most valuable sources of pollen flow for managed and wild bees.

Funkcjonalność zgrzewarek jako jeden z czynników decydujących o jakości połączeń zgrzewanych rur i kształtek z polietylenu Na podstawie dostępnej literatury, obowiązujących aktów normatywnych i instrukcji oraz własnych doświadczeń zostały opracowane wytyczne do oceny funkcjonalności zgrzewarek doczołowych i elektrooporowych stosowanych do łącze-nia rur i kształtek z tworzyw sztucznych. Jednolite wytyczne mogą przyczynić się do poprawy jakości połączeń zgrzewanych, a tym samym do zwiększenia niezawodności pracy sieci gazowych.Słowa kluczowe: gazociąg, rury polietylenowe, zgrzewanie. The functionality of a welding machine, as one of the factors determining the quality of welded polyethylene pipes and fittingsOn the basis of the available literature, normative acts, instructions and own experiences, guidelines have been developed to assess the functionality of butt and electrofusion welding used to connect plastic pipes. Uniform guidelines can help to improve the quality of welded joints and thus increase the reliability of gas networks.

Traditional methods of economic evaluation of projects in the field of environmental protection do not reflect the full value of these projects. In particular, it doesn’t take into account non-market effects that have an impact on the level of social welfare. The issue of valuation of natural resources and related services is also related to this problem. The evaluations and valuations of areas generally ignored the value of natural resources or take into account only the part which has the market value. The article presents the results of study the economy of non-market goods using contingent valuation method. The first part of the results concerns the willingness to pay for improvement of safety sense from flood risk. The second part concerns willingness to pay for the use of municipal sewage treatment plants. The population living of the area of the Żuławy of Vistula delta valued their improvement of safety sense from flood risk of at more than twice the value of the compared to current expenditures incurred flood protection. The vast majority of respondents considered it reasonable protection of polder areas. Indicating simultaneously that in the reduction of flood risk allows possible resettlement and restoration polder parts. The majority of residents (98%) agreed to the construction of wastewater treatment plants and were willing to pay for its construction and operation. The majority of respondents (especially those in middle age and older) found that the collective sewage development would contribute to improving the environment quality and thus the residents living standard. However, not all were willing to pay for the use of collective sewage collection and treatment. 18% of respondents did not want to pay an amount greater than the current charges for the sewage removal and treatment. In addition, the residents of the municipality cannot afford to pay, or believe that water supply and sanitation services should be free.

a b s t r a c t a study on the flowering biology and pollen production of the common laburnum (laburnum anagyroides med.) was conducted under the conditions of lublin during the period 2004 -2006. the flowering of this species began in the second 10-day period of may and lasted for 2.5 -4 weeks. the flowers of common laburnum are borne in showy golden-yellow pendulous racemes. they develop successively, starting from the base and moving to the tip of an inflorescence. during the growing season, one shrub produces 800 to 3200 racemes, with 14 to 35 flowers in a single raceme. on average, the flowering duration for a raceme was 12.8 days and 8.7 days for a single flower. throughout the study years, the shrubs proved to be most attractive in the third 10-day period of may when they reached full bloom. the average weight of pollen produced was 6.08 mg per 10 flowers of laburnum anagyroides, 14.02 mg per raceme, and 26.0 g per shrub. pollen grains reached average dimensions of 24.01 µm × 24.26 µm.