The needs to change EMC standards with respect to mining equipment

W artykule zwrócono uwagę na potrzebę wprowadzenia zmiany wymagań z zakresu kompatybilności elektromagnetycznej, wynikającej ze specyfiki środowiska podziemnych wyrobisk górniczych. Przedstawiono najważniejsze zjawiska elektromagnetyczne występujące w kopalniach, które mogą nie być w wystarczającym stopniu odzwierciedlone w wymaganiach wynikających z obecnego stanu normalizacji. Zaznaczono, że poruszone zagadnienia są jedynie zarysem problemu, mającym na celu zwrócenie uwagi na skalę zjawisk elektromagnetycznych (EM), występujących w podziemnych wyrobiskach kopalni.The article points at the need to change the EMC requirements due to the specifics of underground mining excavations. The most important electromagnetic phenomena in mines were presented. These phenomena may not be reflected properly in the requirements of valid standards. It was stressed that the issues mentioned in the article are only an outline of the problem. The objective is to draw attention to the scale of electromagnetic phenomena occurring in underground mining excavations

Wpływ jonów miedzi na fizjologiczne i biochemiczne zmiany w materiale roślinnym regenerowanym z zarodków androgennych marchwi

Androgenic embryos of 3 different carrot genotypes were cultivated on the medium containing different Cu2+ concentrations: 0.1 uM (control), l uM, 10 uM and 100 uM. Carrot sensitivity to Cu2+was evaluated on the basis of growth inhibition, changes in peroxidation of membranes and proline content. The cultivation on the medium supplemented with Cu2+ resulted in dose-dependent inhibition of the growth and organogenic ability of Narbonne carrot embryos, while in the genotype 1014 treated with 10 uM Cu2+ the significant regeneration ability was obseryed. The same Cu2+ concentration greatly increased the level of free proline in the genotype 1014 which was accompanied by relatively low TBARS content. In the genotype Feria 100 uM Cu2+ concentration triggered large increase in proline content associated with high regeneration capacity of carrot embryos.Zarodki androgenne 3 różnych odmian marchwi hodowano na pożywce z dodatkiem Cu2+ w 4 stężeniach: 0,1 uM (kontr.), l uM, 10 uM, i 100 uM. Wrażliwość marchwi na Cu2+oceniano na podstawie zahamowania wzrostu, zmian w utlenianiu lipidów błonowych oraz zawartości wolnej proliny. Hodowla na pożywce wzbogaconej w Cu2+ spowodowała stopniowe zahamowanie wzrostu oraz zdolności regeneracyjnych zarodków marchwi odm. Narbonne, podczas gdy ilość prawidłowych rozet genotypu 1014 traktowanych 10 uM Cu2+ była największa. Badany metal w tym samym stężeniu znacząco zwiększył zawartość wolnej proliny w rozetach genotypu 1014, co było skorelowane ze stosunkowo niskim poziomem TBARS. Natomiast, w przypadku genotypu Feria, wzrost zawartości proliny skojarzonej z dużymi zdolnościami regeneracyjnymi zarodków zaobserwowano w rozetach traktowanych Cu2+ o stężeniu 100 uM

Trade-offs between activity and thermoregulation in a small carnivore, the least weasel Mustela nivalis

We studied factors influencing daily energy expenditures (DEE) of male least weasels (Mustela nivalis) using the doubly labelled water technique. The relationship between ambient temperature and DEE formed a triangular pattern, characterized by invariance of the maximum DEE and an inverse relationship between minimum DEE and temperature. A simple energetic model relating the DEE of male weasels to activity time (AT) and ambient temperature predicted that, across seasons, less than 10 per cent of measurements approach the upper bound of observed DEE. Male weasels were able to maintain a relatively constant maximum energy output across varying temperatures by adjusting their AT to changes in temperature. They achieved maximum energy expenditures in winter due to high thermoregulatory costs, and in spring and summer due to high levels of physical activity. This pattern exemplifies a ‘metabolic niche’ of a small mammal having extremely high energy expenditures primarily driven by ambient temperature

Energy allocation shifts from sperm production to self-maintenance at low temperatures in male bats

The ability of animals to produce endogenous heat provides a buffer against environmental changes but also incurs high energetic costs. Especially small endothermic mammals have high energy demands. Some temperate-zone species (heterotherms) regularly use torpor, which slows down their entire metabolism but also potentially delays reproduction, to compensate for this. We used a unique experimental approach to test the consequences of extended low and high ambient temperatures on the trade-off in energy allocation to body mass maintenance, thermoregulation effort and seasonal sexual maturation in temperate zone male bats. We showed that long exposure to low ambient temperature shifts energy allocation away from sexual maturation to self-maintenance and results in a delay of sperm maturation by as much as an entire month. This effect was partially buffered by higher body mass. Heavier bats were able to afford more intensive thermoregulation and consequently speed up maturation. Interestingly, bats at constant high temperatures avoided deep torpor and matured faster than those at low temperatures, but sperm production was also slower than under natural conditions. Our results show that not only low, but also constant high ambient temperatures are detrimental during seasonal sexual maturation and the trade-off between investing into self-maintenance and fitness is a finely tuned compromise.publishe