Levels of platinum group elements and rare-earth elements in wild mushroom species growing in Poland

Due to limited data-describing abilities of mushrooms to accumulate platinum group elements (PGEs) and rare-earth elements (REEs), the aim of this study was to determine, by inductively coupled plasma optical emission spectrometry followed by microwave-assisted sample digestion by nitric acid, the content of these elements in 20 mushroom species (10 above ground and 10 growing on wood), mostly edible, collected near a busy trunk road. The highest content of PGEs in above-ground mushroom species was observed in Lepista gilva and Suillus bovinus fruit bodies (0.38 ± 0.05 and 0.37 ± 0.03 mg kg^?1 DW, respectively), while in mushrooms growing on wood, the highest content was observed in Pleurotus ostreatus (0.35 ± 0.04 mg kg^?1 DW). The mean content of PGEs for both these groups was 0.23 ± 0.08 and 0.26 ± 0.07 mg kg^?1 DW, respectively. The highest content of REEs in Suillus luteus and Tricholoma equestra was 5.03 ± 0.50 and 2.18 ± 0.56 mg kg^?1 DW, respectively, but within mushrooms growing on wood in Ganoderma applanatum fruiting bodies it was 4.19 ± 0.78 mg kg^?1 DW. Mean contents of REEs were 1.39 ± 1.21 and 1.61 ± 0.97 mg kg^?1 DW in above-ground species and species growing on wood, respectively. Generally, the group of mushroom species growing on wood was capable of slightly higher accumulation of both REEs and PGEs. No limits have been established for both the groups until now.     

Repeated failure: A source of helplessness or a factor irrelevant to its emergence?

Tested the validity of the egotism model of human helplessness (HE). In contrast to the original theoretical approach of M. E. P. Seligman (1975) and his associates, which points to response–outcome noncontingency as the main source of HE, the egotism alternative proposes that repeated failure itself is the critical determinant of HE symptoms. Repeated failure threatens the self-esteem of the S, who supposedly engages in a least-effort strategy during the test phase of a typical learned HE study, which results in performance impairment. To examine the egotism explanation, we gave Ss noncontingent-feedback training with or without repeated failure on 5 consecutive discrimination problems. In 2 experiments, noncontingent-feedback preexposure produced HE deficits in performance on avoidance learning, whereas repeated failure appeared irrelevant to HE. This and our other findings from research are inconsistent with the egotism explanation and support instead Seligman's original proposal, in which HE is attributed to prolonged experience with noncontingency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Step-out group signatures

Group signature schemes enable to create digital signatures such that the signers are hidden in a group of potential signers. However, in a case of need it is possible to reveal the actual signer either by a group administrator or collectively by the group members. We design a new kind of signatures that we call step-out group signature where the situation is reversed: any member of the group except the signer may prove that he or she was not the signer. This is a dual solution that is useful in certain scenarios: in many cases it is unnecessary to find the signer, it suffices to eliminate some potential signers (e.g. during prosecutions and court procedures). Our solution is more convenient for implementing personal data protection rules: since the signer is not revealed, there is no need to protect this information. On the other hand, the traditional scheme may lead to serious legal problems: if the legal case is to find out whether Bob has created group signature s, it might be illegal to reveal that Alice has created s.     

Effects of changes in MOLB-type SOFC cell geometry on temperature distribution and heat transfer rate in interconnects

A numerical simulation tool for modeling MOLB-type solid oxide fuel cells was described. A mathematical model was developed and simulations were carried out to study the effect of cell geometry on the temperature distribution and heat transfer rate in interconnects. The simulations took into account the impact of co-flow and counter-flow patterns on the distribution of temperature. The results show that in counter-flow conditions there are lower temperature gradients and more uniform temperature distribution, which significantly affects conductive and corrosion properties and durability of the interconnect.