6,399 research outputs found
Assessment of the water quality of ten Waikato lakes based on zooplankton community composition. CBER Contract Report No. 60
Zooplankton communities were documented from ten Waikato lakes from net haul
samples collected in late 2006 and from species hatched from diapausing eggs in
sediments collected in early 2007. Lake trophic state was inferred based on the rotifer
assemblages observed, and these inferred values were compared with predetermined
water quality gradients assessed based on a limited dataset by Environment Waikato
Detection and distribution of Craspedacusta sowerbii: Observations of medusae are not enough
The freshwater cnidarian Craspedacusta sowerbii, native to the Yangtze valley, has invaded lakes and ponds throughout the world. Most distribution records have to date been based on observations of the medusa (jellyfish) stage, including numerous recent publications. We aimed to determine whether polyps are widespread in lakes, and geographical areas, outside of where medusae have been observed, and whether constructed waters are more easily invaded than natural waters. Our results show that C. sowerbii is more common and widespread than is apparent from observations of medusae. We argue that observed occurrences of medusae provide little useful information regarding the distribution of this species, and that published records of new jellyfish occurrences provide unreliable estimates of the timing of introduction, establishment or spread of C. sowerbii in new regions. We found no evidence that constructed waters were more readily invaded than natural waters. Overall, accurate determination of Craspedacusta occurrence and distribution requires systematic surveys of the polyp stages
Computing Variances from Data with Complex Sampling Designs: A Comparison of Stata and SPSS
Most of the data sets available through the National Center for Education Statistics (NCES) are based on complex sampling designs involving multi-stage sampling, stratification, and clustering. These complex designs require appropriate statistical techniques to calculate the variance. Stata employs specialized methods that appropriately adjust for the complex designs, while SPSS does not. Researchers using SPSS must obtain the design effects through NCES and adjust the standard errors generated by SPSS with these values. This presentation addresses the pros and cons of recommending Stata or SPSS to novice researchers. The first presenter teaches research methods to doctoral students and uses Stata to conduct research with NCES data. She uses SPSS to teach her research methods course, due to its user-friendly interface. The second presenter is a doctoral student conducting dissertation research with NCES data. In his professional life as an institutional researcher, he uses SPSS. NCES data sets are a rich resource, but the complex sampling designs create conceptual issues beyond the immediate grasp of most doctoral candidates in the field. The session considers and invites comment on the best approaches to introducing new researchers to complex sampling designs in order to enable them to use NCES data.
Wild record of an apple snail in the Waikato River, Hamilton, New Zealand and their incidence in freshwater aquaria
We report the discovery of a single specimen of a live apple snail Pomacea diffusa Blume 1957 (Ampullariidae: Prosobranchia), from the Waikato River, Hamilton city, central North Island, New Zealand. This species, along with the congeneric P. insularum, is imported for the aquarium trade, and its occurrence in the river likely stemmed from an aquarium release. A survey of 55 aquaria belonging to 43 hobbyists revealed 27 apple snails, with one owner having 22 snails. Assessment of environmental tolerances and impacts of P. diffusa, based largely on studies of the closely related and commonly confused congener P. bridgesii, suggests that direct habitat impacts by this species are likely to be minor. However, there could be indirect influences on native biodiversity through predation on eggs or competition for food supplies with other detritivorous species if densities were to become high. Water temperatures in the Waikato River below Hamilton (10-23˚C in 2009) may enable released individuals to persist for an extended period, and over summer may exceed the threshold required to enable breeding. However, population establishment would be most likely in locations where water is heated through geothermal influences or industrial cooling water discharges
Pharmacy needs global professional standards for education and workforce development.
Catherine Duggan, director of professional development at the Royal Pharmaceutical Society (RPS) and Ian Bates, education adviser to the RPS English Pharmacy Board, discuss the importance of developing a global standard of education and training for pharmacists
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