Direct measurements of biogenic dimethylsulphide fluxes from the oceans : a synthesis

Author Posting. © National Research Council Canada, 2004. This article is posted here by permission of National Research Council Canada for personal use, not for redistribution. The definitive version was published in Canadian Journal of Fisheries and Aquatic Sciences 61 (2004): 836-844, doi:10.1139/F04-047.This paper provides a brief overview of the state-of-the-art of techniques that are currently used for field measurements of trace gas fluxes and the subsequent derivation of gas transfer rates over the oceans. Special attention is given to the relaxed eddy accumulation (REA) and gradient flux (GF) techniques, which rely on empirical functions thus far mainly validated over land. The universality of these functions and their application at sea have not yet been fully evaluated. New experiments have shown that the emission of dimethylsulphide (DMS) can be measured by the REA and GF techniques. Moreover, these measurements have provided parameterizations of gas exchange rates that are within the range of relationships between wind speed and gas transfer that have recently been derived from eddy correlation (EC) and deliberate tracer measurements. Using DMS as a model, gas is potentially a powerful approach to intercalibrate the REA, GF, and EC techniques, test their applicability in the marine environment, and investigate processes that determine trace gas exchange across the ocean surface

Efeito do intervalo das duas últimas inseminações sobre a fertilidade de éguas inseminadas com sêmen fresco diluído Effect of interval between the two last artificial inseminations on mares fertility inseminated with diluted fresh semen

Sessenta e duas fêmeas eqüinas foram distribuídas ao acaso em dois grupos experimentais de acordo com o intervalo da penúltima à última inseminação artificial de cada ciclo (48h ou 72h). As éguas foram rufiadas e inseminadas às segundas, quartas e sextas-feiras, a partir do momento em que apresentavam um folículo de 3,0 a 3,5 cm de diâmetro, com sêmen de apenas um garanhão de fertilidade comprovada, diluído para um volume inseminante de 10 mL com diluidor de mínima contaminação. As taxas de concepção referentes ao primeiro ciclo, para os intervalos de 48h e 72h foram de 66,67% (24/36) e 65,22% (15/23), respectivamente, sendo as taxas de concepção/ciclo de 53,45% (31/58) e 56,76% (21/37), na mesma ordem anterior. Com base nos resultados obtidos, recomendam-se inseminações às segundas, quartas e sextas-feiras, sem perda da fertilidade.<br>Sixty two mares were randomly assigned to two experimental group, according to two intervals between the penultimate and the ultimate artificial insemination (48 or 72h). The mares were teased and inseminated on monday, wednesday and friday, when a follicle size was equal or greater than 3.0 cm in diameter, with semen from a stallion of proven fertility diluted with minimum contamination extender. The conception rates for the first cycle for the 48h and 72h intervals were 66.67% (24/36) and 65.22% (15/23) respectively, and the conception/cicle were 53.45% (31/58) and 56.76% (21/37), in the same order. Based on these results, one should consider recommending inseminations on monday, wednesday and friday, without fertility loss