Cuando la morfología y los marcadores moleculares entran en conflicto: el ejemplo de los anfípodos subterráneos de la región de Pilbara, Australia Occidental

Fifteen species of groundwater amphipods in the genus Chydaekata have been described from the Pilbara, Western Australia, each restricted to a single bore. Dewatering at a local mine site was halted while a second survey was undertaken. Newly collected samples were identified using the existing key, and allozyme analysis was used to test species boundaries. Allozymic diversity was not associated with single bores, and only two distinct genetic groups (one of which was very rare), were identified. Based on these results, and the finding that species were found to be more widespread, the Western Australian Environmental Protection Authority recommended that dewatering continue with caution at the site. This study provides an example of the problems associated with incongruent data sets, and the difficulties inherent in working with rare species, namely, interpreting the results of studies based on small samples or incomplete collections.Se han descrito quince especies de anfípodos de aguas subterráneas del género Chydaekata que habitan en la región de Pilbara, Australia Occidental, restringiéndose cada una de ellas a una única perforación. Mientras se elaboraba un segundo estudio, se interrumpió el desagüe que se estaba llevando a cabo en un emplazamiento minero local. Las nuevas muestras recolectadas se identificaron utilizando la clave existente, mientras que para verificar los límites de la especie se recurrió a un análisis alozimático. La diversidad alozimática no se asoció con perforaciones únicas y sólo se identificaron dos grupos genéticos bien diferenciados (uno de los cuales era muy poco común). Basándose en estos resultados y en el hallazgo de que la especie estaba más extendida, el Organismo de Protección Medioambiental de Australia Occidental recomendó que se actuara con cautela al proceder con el desagüe. El presente estudio brinda un ejemplo de los problemas asociados con conjuntos de datos incongruentes, así como las dificultades que conlleva trabajar con especies poco comunes, especialmente en lo que respecta a la interpretación de los resultados de estudios basados en pequeñas muestras o recolecciones incompletas

Brookhaven National Laboratory Report BNL-1313

A number of pipetting aids are commercially available which obviate the necessity of filling pipets by oral suction. Most of the commercially available devices involve fitting the pipet into a soft tight fitting bushing and filling by means of either a piston or a rubber bulb. The pipet is then emptied by means of a valve control which permits, it is claimed, a dispensing accuracy of 0.1mL. It is at once apparent that the probable error (10% for a 1 mL. pipet) is considerably greater than is permissible for great precision. In practice these devices are found to be awkward and after a period of use tend to become even more so due to corrosion of the valve and aging of the rubber bushing and rubber bulbs

Activation of Tl, Pb and Bi by 10-160 MeV Neutrons: Possible Application to the Analysis of Bi

The medium energy intense neutrons (MEIN) available at the Brookhaven Chemistry Linac Irradiation Facility have an energy distribution up to approx. 160 MeV and an effective neutron flux of approx. 1.3 x 10/sup 11/ cm/sup -2/ s/sup -1/. The present work explores the feasibility of using this facility for the analysis of Tl, Pb and Bi by activation with MEIN. The most sensitive reactions, from a practical standpoint, were found to be Tl (n, xn) /sup 200/Tl (x = 4, 6), Pb (n, xn) /sup 204//sup m/Pb (x = 0, 3, 4, 5) and /sup 209/Bi (n, 6n) /sup 204/Bi. The absolute sensitivities attainable with these reactions are 0.1, 0.05 and 0.08 ..mu..g of Tl, Pb and Bi respectively, for 1 h irradiation at 1.3 x 10/sup 11/ n cm/sup -2/ s/sup -1/ with samples counted 2 h after the end of irradiation. The advantages of the method over thermal neutron activation analysis are that all three elements can be assayed at the sub-microgram concentration levels by ..gamma..-spectrometry with the help of a simple radiochemical purificaton and the analytical results can be verified by cross checking via the multiple (n, xn) reaction products. However, interference from Bi in the determination of Pb and from Pb and Bi in the determination of Tl limits its usefulness to the analysis of Bi

When morphology and molecular markers conflict: a case history of subterranean amphipods from the Pilbara, Western Australia

Fifteen species of groundwater amphipods in the genus Chydaekata have been described from the Pilbara, Western Australia, each restricted to a single bore. Dewatering at a local mine site was halted while a second survey was undertaken. Newly collected samples were identified using the existing key, and allozyme analysis was used to test species boundaries. Allozymic diversity was not associated with single bores, and only two distinctgenetic groups (one of which was very rare), were identified. Based on these results, and the finding that species were found to be more widespread, the Western Australian Environmental Protection Authority recommended that dewatering continue with caution at the site. This study provides an example of the problems associated with incongruent data sets, and the difficulties inherent in working with rare species, namely, interpreting the results of studies based on small samples or incomplete collections