نتایج جستجو برای: stream gradient

تعداد نتایج: 182720  

Journal: :Dong wu xue yan jiu = Zoological research 2014
Xiao-Yun Sui Zhi Lu Yun-Zhi Yan Yi-Feng Chen Yin-Tao Jia

Using seasonally collected data (2009-2010) from 15 sampling sites that represent first- to fifth-order streams within the Qingyi watershed, we examined the spatio-temporal patterns of fish assemblages along two longitudinal gradients to explore the effects of a large dam on fish assemblages at the watershed scale. No significant variation was observed in either species richness or assemblage s...

2004
Randall J. Hunt Mac Strand John F. Walker

Measurements of groundwater–surface water exchange at three wetland stream sites were related to patterns in benthic productivity as part of the US Geological Survey’s Northern Temperate Lakes–Water, Energy and Biogeochemical Budgets (NTL–WEBB) project. The three sites included one high groundwater discharge (HGD) site, one weak groundwater discharge (WGD) site, and one groundwater recharge (GR...

Simultaneous effects of slip and heat transfer on peristaltic transport of an incompressible electrically conducting viscous fluid  in an  asymmetric channel is studied under the assumptions of long wavelength and low Reynold number .The  asymmetry is produced by choosing the peristaltic wave train on the walls to have different amplitudes and phase.Exect solutions for stream function,velocity ...

Journal: :Journal of environmental quality 2012
John B Dybkjær Annette Baattrup-Pedersen Brian Kronvang Hans Thodsen

The present study was conducted in 47 different riparian areas distributed throughout Denmark to investigate diversity and distributional patterns of plant communities along a lowland stream size gradient (first to fifth order). The investigated areas were representative for Danish riparian areas not in use for agricultural production. We investigated plant community richness along a stream siz...

2017
Rikhi Bose Paul A. Durbin

Observations are presented to show that in an adverse pressure gradient boundary layer, beneath free-stream turbulence, the interaction between Klebanoff streaks and naturally arising instability waves leads to helical disturbances which break down to form turbulent spots. This occurs under low to moderate levels, 1%–2%, of free-stream turbulence. At high levels of free-stream turbulence, conve...

2008
Eric J. Caldera Daniel I. Bolnick

Question: How do post-glacial colonization history and current watershed geomorphology affect population genetic structure in lacustrine fish populations? Study system: Eleven populations of lacustrine threespine sticklebacks (Gasterosteus aculeatus) from a single watershed, and two adjacent marine populations of G. aculeatus as outgroups. Methods: Individuals were genotyped using six microsate...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علوم پایه دامغان - دانشکده علوم زمین 1387

چکیده ندارد.

2005
EDWARD A. KELLER

Stream channel development in forested areas is profoundly influenced by large organic debris (logs , limbs and rootwads greater than 10 cm in diameter) in the channels. In low gradient meandering streams large organic debris enters the channel through bank erosion , mass wasting, blowdown, and collapse of trees due to ice loading. In small streams large organic debris may locally influence cha...

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