ion; depletion; hydropower; river; run-of-river; small-scale; weir.

The effect of the outlet weir height on sieve tray performance is described in this paper. The studies were made to investigate the effect of the outlet weir height on sieve tray mass transfer efficiency and hydraulic performance. Tests were conducted in the 1.22 m diameter section of the Fractionation Research, Inc. (FRI) low-pressure column. Sieve trays with nominal hole areas of 14%, 13%, an...

Otiditaenia macqueeni, Raillietina sp., Paronchocerca tonkinensis, and Allodapa sp. were recovered from a group of rufous-crested bustards {Eupoditis ruficrista) which died after importation into the United Arab Emirates. Associated findings at postmortem examination in cluded cardiac rupture, weight loss, trichomoniasis, and enteritis. Histologie examinations revealed Paronchocerca sp. microfi...

Although amphibians have been widely promoted as indicators of biodiversity and environmental change, rigorous tests are lacking. Here key indicator criteria are distilled from published papers, and a species that has been promoted as a bioindicator, the great crested newt, is tested against them. Although a link was established between the presence of great crested newts and aquatic plant dive...

The objective of this study is to evaluate the ectoparasites and helminths of the white-crested elaenia, Elaenia albiceps chilensis. Feather mites Anisophyllodes elaeniae, Trouessartia elaeniae, and Analges sp. were detected in 51% of birds (n=106), whereas 24% were infected with lice (Tyranniphilopterus delicatulus, Menacanthus cfr. distinctus, and Ricinus cfr. invadens). Helminths Viguiera sp...

The objective of this study is to evaluate the ectoparasites and helminths of the white-crested elaenia, Elaenia albiceps chilensis. Feather mites Anisophyllodes elaeniae, Trouessartia elaeniae, and Analges sp. were detected in 51% of birds (n=106), whereas 24% were infected with lice (Tyranniphilopterus delicatulus, Menacanthus cfr. distinctus, and Ricinus cfr. invadens). Helminths Viguiera sp...

An experimental campaign is undertaken in order to investigate the hydraulic features of a vertical drop shaft, also considering the influence of a venting system consisting of a coaxial vertical pipe, projecting within the drop shaft with different plunging rates. Three different flow regimes are observed: a “weir flow” for very low head values, where the flow profile is subject to the atmosph...

This study presents a spatial analysis of physical and biotic river conditions below a low head hydro scheme in the River Goyt, UK. The overall aim was to assess whether changes in localized hydrological features, introduced by low head hydro, affect phytobenthic biomass. Single point and profile measurements of flow velocity and velocity vectors, elevation, depth and biofilm biomass were mappe...

This article presents the longue durée social history of a medieval fish weir. It reveals significant role fishing and weirs in construction reconstruction structures cultural identities. focuses on an enigmatic annual ceremony – Horngarth or Penny Hedge at Whitby, North Yorkshire. The begins by arguing that descends from intertidal weir, before exploring possible contexts which weir originated...

We show that the class of level-k control languages, as defined by Weir, is properly included in the class of 2 k−1-multiple context-free languages for each k ≥ 2. The proof of inclusion uses a representation of the set of derivation trees for a level-k control language in terms of a second-order abstract categorial grammar. 1.1 Introduction Weir (1992a) introduced a hierarchy of language class...