Unionid Mussels from Nearshore Zones of Lake Erie

Concern exists that the introduction of dreissenid mussels following long-term effects of pollution may have completely eliminated native mussel species from Lake Erie. Natural seiche events were used to facilitate surveys for live unionids on five occasions in the western basin of Lake Erie and Sandusky Bay between 2007 and 2009, and beach and estuary surveys were conducted at numerous additional sites between 2004 and 2009. Sixteen unionid species were found living in or near Lake Erie, including six sites in the nearshore zone of the lake. Each community consisted of live individuals from two to eight species, and evidence included live and/or fresh dead material from several state listed species at multiple sites. Where estimated, the mean overall density was low at 0.09 unionids/m2, although similar to other known unionid refuges in the lower Great Lakes. While the ephemeral nature of seiche events makes them a limited survey tool, their application combined with increasing numbers of fresh shells washing ashore over the past few years indicates that unionids are extant in the western basin of Lake Erie, and may further suggest that conditions may be improving for native mussel species

Estoques de carbono e fluxos de gases de efeito estufa em plantios de pinus.

Resumo

Selectivity threshold between mono-carrier and multi-carrier solutions

This paper compares the capacity obtained either with a mono-carrier waveform or with a multi-carrier waveform with respect to the channel selectivity. Analysis is given considering the Peak- to Average-Power Ratio of the retained solutions. A new mixed approach is proposed. It is based on a selectivity threshold definition showing where we should use a mono-carrier approach and where the multi-carriers approach gives a higher capacity.Cet article présente une comparaison des capacités obtenues avec une forme d’onde mono-porteuse et une forme d’onde multi-porteuses en fonction de la sélectivité du canal de transmission. L’analyse est menée en considérant avec attention le facteur de crête de la forme d’onde choisie. Une approche mixte avec un seuil de basculement d’une forme d’onde à l’autre est proposée

Efficient Electrocatalytic CO2 Reduction Driven by Ionic Liquid Buffer‐Like Solutions

We show here that electrocatalysis of CO2 reduction in aqueous electrolytes containing the ionic liquid (IL) 1-n-butyl-2,3dimethylimidazolium acetate ([BMMIm][OAc]) and dimethyl sulfoxide (DMSO) proceeds at low overpotentials (−0.9 V vs. Ag/AgCl) at commercially-available Au electrodes, and with high selectivity for CO production (58% faradaic efficiency at –1.6 V vs Ag/AgCl). 0.43 mol of CO2 per mol of IL can be absorbed into the electrolyte at atmospheric pressure, forming bicarbonate and providing a constant supply of dissolved CO2 to the surface of the electrode. We also show that electrocatalysis of CO2 reduction in the electrolyte is facilitated by stabilization of CO2 radical anions by the imidazolium cations of the IL and buffer-like effects with bicarbonate