we proposed to use artificial channels in laboratory assays to expose periphyton to substancesreleased in rural environments in order to test the following hypotheses 1) a high concentration of humicsubstances decreases the biofilm biomass and alters its metabolism; 2) periphyton biomass and metabolism increase in response to nutrient addition in spite of the previous high nutrient concentratio...

Potassium is a major nutrient which may play an important role in many processes such as ion homeostasis in plant cells and osmotic adjustment of guard cells during stomatal opening and closing. Pathumthani 1 (PT1) rice has been reported as being a salt sensitive cultivar and has been selected as a model plant in this study to investigate the possibility of improving the osmotic potential, pigm...

Little attention has been paid to the diagnosis of deficiencies of micronutrients such as zinc (Zn) and boron (B) and secondary nutrient such as sulphur (S) in rainfed systems. We evaluated Zn, B and S status of 1617 farmers’ fields in 14 districts of the semi-arid tropical India. Results showed that most of the soil samples were low to medium in organic carbon contents. Results also revealed t...

background and objectives: the quefts model is using for optimizing fertilizer managements in crops, but it has not been used in iran yet. quefts accounts for interactions among npk affecting the ie of n, p and k and allows differentiation according to different yield levels targeted. it is necessary to determine crops parameters before application the model in the studying area. the first step...

abstract date palm, phoenix dactylifera, is one of the most important horticultural crops in iran. the most soils in iran, especially those cultivated with palm, are calcareous with high ph. the high ph of soil causes reduction of nutrient elements absorption. findings of researches show that application of elemental sulfur along with tiobacillus bacteria in soil, due to sulfur oxidation, reduc...

V porovnaní so sekvenčnými výpočtami sú výpočty využívajúce paralelizmus výrazne zložitejšie. Z teoretického pohl’adu je vel’mi prirodzeným modelom paralelných výpočtov model PRAM, ktorý je analógiou modelu RAM často používaného v teórii zložitosti. Z praktického pohl’adu je však zaručenie úplnej synchronizácie a uniformného prístupu k zdiel’anej pamäti, garantovaných modelom PRAM, značne probl...

Storm events can pulse nutrients and carbon from soils and provide an important subsidy to food webs in oligotrophic streams and lakes. Bacterial nutrient limitation and the potential response of stream aquatic bacteria to storm events was investigated in arctic tundra environments by manipulating both water temperature and inorganic nutrient concentrations in short (up to 4 days) and long dura...

Introduction: Resveratrol (3,5,4-trihydroxystilbene) a non-flavonoid polyphenol found in some plants like grapes, peanuts and pomegranates, possesses a wide range of biological effects. Evidence indicates that resveratrol has beneficial effects on nervous system to induce neuroprotection. However, the cellular mechanisms of the effects are not fully determined. In the present study, the cellula...