Hand-rearing giraffe calves is a challenging, timeconsuming and labour-intensive process. There appears to be high individual variability among different calves. Different feeding schedules and milk substitutes have been used and are discussed. The use of whole cow's milk is recommended and can be mixed with different supplements or calf milk replacers. The authors recommend weaning the calf around 1 year of age.
In order to determine copper toxicity (LC50) to a local species (Cnesterodon decemmaculatus) in the South American Pilcomayo River water and evaluate a cross-fish-species extrapolation of Biotic Ligand Model, a 96 h acute copper toxicity test was performed. The dissolved copper concentrations tested were 0.05, 0.19, 0.39, 0.61, 0.73, 1.01, and 1.42 mg Cu L−1. The 96 h Cu LC50 calculated was 0.655 mg L−1 (0.823 − 0.488). 96-h Cu LC50 predicted by BLM for Pimephales promelas was 0.722 mg L−1. Analysis of the inter-seasonal variation of the main water quality parameters indicates that a higher protective effect of calcium, magnesium, sodium, sulphate, and chloride is expected during the dry season. The very high load of total suspended solids in this river might be a key factor in determining copper distribution between solid and solution phases. A cross-fish-species extrapolation of copper BLM is valid within the water quality parameters and experimental conditions of this toxicity test.
At Zurich Zoological Gardens 3.1 Geochelone elephantopus and 2.4 G. gigantea are maintained in an enclosure comprised of a 400 m2outdoor area, which contains a shelter with a heated floor to which the tortoises have constant access, and an adjacent 65 m2indoor house with a partially heated floor, where the temperature reaches 30oC. In 1984 the diet offered was adjusted to a lower protein, higher fibre composition after one animal died from chronic kidney disease and visceral gout. No eggs have been produced by G. gigantea while maintained at the Zoo because the ♀ have failed to ovulate which may be an indicator of unfavourable environmental conditions, such as low ambient temperatures. Since 1989 six G. elephantopus have hatched at the Zoo. Details
Palabras clave: río urbano, contaminación, efluentes, escorrentía pluvial RESUMEN El río Matanza-Riachuelo constituye un ejemplo claro y extremo del "síndrome del río urbano" y un caso emblemático de contaminación en Argentina. A partir de los datos generados en el monitoreo de la calidad de agua superficial del Riachuelo (tramo inferior del río Matanza) que realiza la Agencia de Protección Ambiental del Gobierno de la Ciudad de Buenos Aires, se evaluó la evolución de la calidad del agua (periodo 2008-2016). Para ello, se aplicó la prueba estadística de Mann-Kendall a la serie de datos para cinco variables fisicoquímicas, una microbiológica y la precipitación acumulada mensual para el área. Los resultados reflejaron condiciones más favorables en cuanto a contenido y demanda biológica de oxígeno, nitrógeno amoniacal total y ion cloruro aguas arriba de la desembocadura. La abundancia de bacterias Escherichia coli no mostró una tendencia apreciable. Asimismo, la fracción de materia orgánica no biodegradable se habría incrementado en todo el tramo al igual que la precipitación acumulada mensual para el periodo estudiado. El incremento de la escorrentía pluvial habría determinado las tendencias observadas en el intervalo de tiempo considerado. Aun así, el ecosistema permaneció en un estado altamente degradado con el 50 % de los valores registrados de oxígeno disuelto por debajo de 2 mg/L y el 50 % de los valores de demanda biológica y demanda química de oxígeno por encima de 15 y 50 mg O2/L, respectivamente. Los números de E. coli, por su parte, resultaron similares a los de un efluente cloacal crudo.
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