نتایج جستجو برای: sediment
تعداد نتایج: 36882 فیلتر نتایج به سال:
The specificity and sensitivity of indirect ELISA, based on the use of four different antigenic extracts obtained from a clinical isolate of Salmonella enteritidis, were compared with those obtained with the gm-flagellin based ELISA (IDEXX). A total of 116 serum samples from salmonellae free, naturally infected and vaccinated hens were studied. The results showed that the indirect ELISA, based ...
The monitoring of pharmaceuticals and personal care products (PPCPs) has focused on the distribution in rivers and small lakes, but data regarding their occurrence and effects in large lake systems, such as the Great Lakes, are sparse. Wastewater treatment processes have not been optimized to remove influent PPCPs and are a major source of PPCPs in the environment. Furthermore, PPCPs are not cu...
This study reviews certain physiological digestive parameters in the literature that could be used to predict tissue residues in aquatic oligochaetes using the biodynamic model. Predictions were evaluated with independently measured Cd bioaccumulation data in sediment bioassays and field oligochaetes. The parameter review focused on three species commonly used in ecotoxicity testing and bioaccu...
We consider the theory of erosion and investigate connections to the theory of optimal transport. The mathematical theory of erosion is based on two coupled nonlinear partial differential equations. The first one describing the water flow can be considered to be an averaged NavierStokes equation, and the second one describing the sediment flow is a very degenerate nonlinear parabolic equation. ...
suspended sediment estimation is an important factor from different aspects including, farming, soil conservation, dams, aquatic life, as well as various aspects of the research. there are different methods for suspended sediment estimation. this study aims to estimate suspended sediment using feed forward neural network with error back propagation with levenberg-marquardt back propagation algo...
the behavior of suspended sediment during flood events is not only a function of energy conditions, i.e. sediment is stored at low flow and transported under high flow conditions, but also is related to the variations in sediment supply and sediment depletion. these changes in sediment availability result in so-called hysteresis effects. therefore, hysteresis pattern analysis is of great import...
Uncertainties in sediment quality assessments are discussed in five categories: (1) sediment sampling, transport and storage; (2) sediment chemistry; (3) ecotoxicology; (4) benthic community structure; and (5) data uncertainties and QA/QC. Three major exposure routes are considered: whole sediments, and waters in sediment pores and at the sediment-water interface. If these uncertainties are not...
The authors employed complex model for Cs-137 concentration in seawater and sediment to represent the spatially heterogeneous distribution in sediment. I don’t agree with their results of total amount of Cs-137 in sediment which is 10 times larger than previous estimated value based on observation. Main problem is that they only considered sedimentation and resuspension process in a similar man...
Here we provide global estimates of the seasonal flux of sediment, on a river-by-river basis, under modern and prehuman conditions. Humans have simultaneously increased the sediment transport by global rivers through soil erosion (by 2.3 +/- 0.6 billion metric tons per year), yet reduced the flux of sediment reaching the world's coasts (by 1.4 +/- 0.3 billion metric tons per year) because of re...
The methods available in the literature for sediment concentration estimation are complicated and time consuming and necessitate cumbersome parameter estimation procedures. In this study, artificial neural networks (ANNs) are used to forecast and estimate sediment concentration values. The forecasting results obtained using previously observed sediment values were close to the real ones. The se...
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