Frasnian bryozoans (Late Devonian) from the Khoshyeilagh Section,Alborz Mountains (northern Iran)

A bryozoan fauna containing seven species is described from the Upper Frasnian (Upper Devonian) rocks in the Khoshyeilagh Section, Alborz Mountains (northern Iran). The studied bryozoan assemblage includes one new trepostome species, Eridotrypella alborzensis sp. nov., an additional four species identified at species level: two trepostomes, Minussina akkayaensis Volkova, 1974 and Leptotrypella inaudita Morozova, 1961, and two rhabdomesine cryptostomes, Bigeyella mariae (Morozova, 1961) and Saffordotaxis multispinata (Morozova, 1955). Furthermore, two species are described in open nomenclature: the trepostome Schulgina sp. and the rhabdomesine cryptostome Nicklesopora sp. The studied fauna shows a close similarity at the species level between northern Iran and the Altai-Sayan Folded Belt (Russia), south China, and Transcaucasia.     

Environmental Factors Affecting the Compressive Strength of Microbiologically Induced Calcite Precipitation-Treated Soil

Some microorganisms such as Sporoscarcina pasteurii precipitate calcium carbonate and are suitable for biocementation. This study aimed to investigate the effects of several factors including concentration of bacteria, chemical reactants, temperature, and pH on precipitation of calcium carbonate. The results showed that after 7 and 14 days of curing, the compressive strength of silty clay soil samples increased steadily as pH increased from 5 to 9. It was observed that pH plays an important role in biocementation. The highest compressive strength (i.e. 92 kPa) was observed when the soil was treated with 50 ml of bacterial solution after 14 days of curing. In addition, it was observed that the highest compressive strength of samples was achieved when the temperature was 40°C.     

The Effect of Transthylakoid Proton Uptake on Cytosolic pH and the Imbalance of ATP and NAPDH/H+ Production as Measured by CO2- and Light-Induced Depolarisation of the Plasmalemma

The light-induced changes of plasmalemma potential and of chlorophyllfluorescence were compared with changes induced by the modulationof O₂- or CO₂-concentration. The fast depolarisation of plasmalemmapotential upon illumination as labeled by the time-constant