slow sand filters are as a proper technology for pre-treatment of raw water, with a fine and medium trubidity in small communities in developing countries. thus, with a minimum operation cost and minimum need for expest bodies have the maximum efficiency. the purpose of this research is carried out to evaluate the efficiency of two processes of horizontal flow roughing filter and vertical flow ...

A new chitinase inhibitor, CI-4, was isolated from the culture broth of a marine bacterium Pseudomonas sp. IZ208. The structure of CI-4 was determined to be cyclo(L-Arg-D-Pro) by spectral studies and comparison with a synthetic sample. CI-4 showed inhibitory activity against chitinase.

In hands-free telephones and teleconferencing systems, acoustic echo cancellers are required, which are often implemented by adaptive filters. In these applications, the speech input signal of the adaptive filter is highly correlated and the impulse response of the echo path is very long. These characteristics will slow down the convergence rate of the adaptive filter if the well-known normaliz...

the objective of the present investigation was to determine the seroprevalence of coxiella burnetii infection in free-range yaks in china. a total of 552 serum samples were collected from yaks in gansu province, northwest china between april 2013 and january 2014, and antibodies against c. burnetii were evaluated using enzyme-linked immunosorbent assay (elisa). overall, 13.59% (75/552, 95% ci: ...