نتایج جستجو برای: as well as sediment grain size

تعداد نتایج: 6215636  

2016
Pollyanna Hardy Jennifer L Bell Peter Brocklehurst

BACKGROUND A systematic review on the use of incentives to promote questionnaire return in clinical trials suggest they are effective, but not all studies have sufficient funds to use them. Promising an incentive once data are returned can reduce the cost-burden of this approach, with possible further cost-savings if the offer were restricted to reminder letters only. This study aimed to evalua...

2012
Senapathi VENKATRAMANAN Thirunavukkarasu RAMKUMAR Irudhayanathan ANITHAMARY Govindaraj RAMESH

The distribution of grain size parameters along 11 km stretch of the beach sediments between Karikal and Nagore, reveals that the mean grain size exhibits a marked decreasing trend on either side of the mouth of the Tirumalairajanar River which flow from west to east. The sediments are mainly of medium to coarse grained, moderately sorted, near-symmetrical skewed to fine skewed and leptokurtic ...

2015
Liangang Xiao Yaxian Hu Philip Greenwood Nikolaus J. Kuhn Saskia Keesstra

The use of sediment settling velocity based on mineral grain size distribution in erosion models ignores the effects of aggregation on settling velocity. The alternative approach, wet-sieved aggregate size distribution, on the other hand, cannot represent all destructive processes that eroded soils may experience under impacting raindrops. Therefore, without considering raindrop impact, both me...

Journal: :علوم گیاهان زراعی ایران 0
حمیدرضا عیسوند استادیار دانشکدۀ کشاورزی دانشگاه لرستان علیرضا اسماعیلی دانشجوی دکتری فیزیولوژی گیاهان زراعتی پردیس کشاورزی و منابع طبیعی دانشگاه تهران مراد محمدی دانشجوی دکتری فیزیولوژی گیاهان زراعتی دانشکدۀ کشاورزی دانشگاه تبریز

an experiment was conducted as a split plot based on complete randomized block design with three replications in the fall of 2010 at the farm of lorestan university, khorramabad, iran. four winter wheat cultivars (marvdasht, azar, shiraz and line m-79-7) as the main plot and levels of iron oxide nanoparticles (ion) along with control treatment were the subplot. iron fertilizer spraying was done...

2017
Sterling B Tebbett Christopher H R Goatley David R Bellwood

Sediments are found in the epilithic algal matrix (EAM) of all coral reefs and play important roles in ecological processes. Although we have some understanding of patterns of EAM sediments across individual reefs, our knowledge of patterns across broader spatial scales is limited. We used an underwater vacuum sampler to quantify patterns in two of the most ecologically relevant factors of EAM ...

Journal: :Ecology 2015
L K Albertson D C Allen

An increasing number of studies have emphasized the need to bridge the disciplines of ecology and geomorphology. A large number of case studies show that organisms can affect erosion, but a comprehensive understanding of biological impacts on sediment transport conditions is still lacking. We use meta-analysis to synthesize published data to quantify the effects of the abundance, body size, and...

2013
Andrea Nicastro Melanie J. Bishop

Among the impacts of coastal settlements to estuaries, nutrient pollution is often singled out as a leading cause of modification to the ecological communities of soft sediments. Through sampling of 48 sites, distributed among 16 estuaries of New South Wales, Australia, we tested the hypotheses that (1) anthropogenic nutrient loads would be a better predictor of macrofaunal communities than est...

Erosion is one of the most destructive and continuous phenomena that cannot be prevented and only could be controlled by studying the chemical and physical properties of soil. Marls are one of the most important sedimentary units in Iran which have high rate in sediment production and erodibility because of their Physico-chemical characteristics. These properties caused large environmental and ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - دانشکده علوم 1389

fluorescence chemical sensors for the highly sensitive and selective determination of pb2+ , hg2+, co2+ and fe3+ ions in aqueous solutions are described. the ion sensing system was prepared by incorporating lipophilic ligand (l) as a neutral ion-selective fluoroionophore in the plasticized pvc membrane containing sodium tetraphenylborate or potasium tetrakis (p-chlorophenyl) borate as a liphoph...

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