modern research physics

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Microalgae are cosmopolitan microorganisms and minerals are considered as limiting factors for growth of them. In the present study cyanobacteria were isolated and indentified and also the effect of different media on their growth was examined. Consequently, two new species of cyanobacteria belonged to the family of Oscillatoriaceae were isolated and reported for the first time from Tehran province. To this end, soil samples were collected from Tehran Province in summer 2008. Samples were cultured in BBM & N8 media to evaluate the effect of nutrients on the growth of microalgae. Isolation was carried out by several subcultures. Morphological indentification was done using systematics keys and partial sequencing of 16S rRNA was used for molecular identification. The results showed that two species were recorded from Tehran Province, Leptolyngbya sp. ISC 40 Gomont and Leptolyngbya sp. ISC 25 Gomont. The collected soil samples were analyzed physically and chemically. Results indicated that BBM medium was suitable for isolation and as indicated by infertility of cultured soils, two identified species are resistance to environmental factors.

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Deltas of the most important morphological units are a tremendous effect on agricultural activities, mining, coastal management and etc. Despite appropriate soil and water resources deltas, are influenced by environmental phenomena such as climate change and sea level changes. The effect of these changes will appear on physico-chemical, mineralogical deposits. This study was conducted to analyze the Karkheh delta depositional environments based on the chemical characteristics of ancient sediments. Depositional environments and locations of core were identified using digital data processing, geomorphology mapping and initial visit of the area. The coring was carried out with rotary drilling machine and continuously to a depth of ten meters in jofeir and Rofayeh. Among The cores, 20 samples were selected for mineralogical and chemical tests. Differences in chemical and mineralogical characteristics revealed at least three major discontinuities exist between sedimentary layers to a depth of 10 m. In addition, thickness and type of the sediment are not same conditions and it changes depending on the stability of depositional environments. Increasing of Mg / Ca, magnesium and salinity, and reducing of clay particles, show Sedimentary environments trend is toward dry conditions and high energy environments at depths from 10 to 5 meters. In contrast, the depth of 5 to 4 and 3 to 0 meter this trend towards more humid climate and low energy environments. Therefore, it is concluded that the depositional environment of the Karkheh River delta at the upper Holocene is not constant, and this has led to changes in the delta.

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Garnet-micaschists from Haji Qara high, north of Golpayegan, are part of the metamorphic rocks of the Sanandaj-Sirjan Zone (SSZ). Lepidoporphyroblastic and porphyropoikiloblastic are the main textures and the mineral assemblages consist dominantly of Fe-biotite, muscovite and ferriphengite, metamorphic Fe-Mg chlorites (I-type and IIb), garnet and quartz. Staurolite, andalusite, plagioclase carbon, Fe-oxides and tourmaline are present as accessories. Petrographic evidences as well as mica chemistry along with other paragenesis and thermometric estimations indicate a path change from amphibolites facies to lower pressure and higher temperature gradient suggesting the presence of a local pluton which led to garnet porphyroblast, biotite and muscovite (overprinted in different orientation) and andalusite crystallization. The occurrence of chlorite, ferriphengite and Fe-oxides demonstrate a retrograde metamorphism during uplift and decompressional cooling path in the area.