1,721,014 research outputs found
Species-specific effects on hemolymph glucose control by serotonin, dopamine, and L-enkephalin and their inhibitors in Squilla Mantis and Astacus Leptodactylus (Crustacea)
No full textHemolymph glucose level is controlled by crustacean Hyperglycemic Hormon
Heavy metal toxicity and differential effects on the hyperglycemic stress response in the shrimp Palaemon elegans
No full textDifferent bacterial lipopolysaccharides as toxicants and stressors in the shrimp Palaemon elegans
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Heavy metals affect the circulating haemocyte number in the shrimp Palaemon elegans
No full textEnvironmental contamination by heavy metals produced by either anthropogenic or natural activities represents a threat to many species of aquatic animals worldwide. This study investigates the effect of short-term (96 h) exposure to dissolved heavy metals on the number of circulating haemocytes in the shrimp, Palaemon elegans (Rathke). Changes in haemocyte counts were determined in relation to time of exposure and with heavy metal concentration, relating the results to toxicity. It was found that immersion in artificial seawater containing Hg, Cd, Cu, Cr, Zn or Pb caused a decrease in the haemocyte count during the first 8 h exposure, although the haemocyte number returned to the initial (time 0) levels over the following 16 h immersion. In each case, the decrease in circulating haemocyte count induced by these metals was significantly different from the controls. The greatest decrease in haemocyte numbers (haemocytopenia) was induced by Pb, followed, in descending order, by Zn, Hg, Cr, Cu and Cd. The lethal level of haemocytopenia for the shrimps, defined as the number of haemocytes ml(-1) remaining in moribund animals (i.e. threshold of mortality) was found to be significantly lower than the levels tolerated by surviving shrimps (i.e. the limit of survival). The percentage of haemocytes remaining in the circulation at the threshold of mortality as a function of the number at time 0 was 56.6 +/- 8.8%. By contrast, the equivalent value for the threshold of survival was 63.7 +/- 12.4%. Importantly, the percentage decrease in haemocyte counts tolerated by P. elegans appears to vary with the metal. Animals treated with Ph or Zn survived with a lower number of circulating haemocytes than animals exposed to the other heavy metals. (C) 2001 Academic Press.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Accuratezza della documentazione clinica ospedaliera nella tracciabilità delle infezioni correlate alle pratiche assistenziali
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