scholarly journals Effects of the antidepressant fluoxetine on pigment dispersion in chromatophores of the common sand shrimp, Crangon crangon: repeated experiments paint an inconclusive picture

Ecotoxicology ◽  
2020 ◽  
Vol 29 (9) ◽  
pp. 1368-1376
Author(s):  
Alex T. Ford ◽  
Eleanor Feuerhelm

Abstract The effects of antidepressants in the environment are starting to generate considerable interest due to the fact that neurotransmitters influence a range of biological processes. Crypsis is an important behavioural and physiological response in many crustaceans modulated by monoamine and pigment dispersing/concentrating hormones. This study aimed to develop a test methodology and investigate the effects of the selective serotonin reuptake inhibitor (SSRI), fluoxetine, on a chromatophore index and overall carapace ‘darkness’ in the common sand shrimp Crangon crangon. Adult shrimp were exposed for either 1 h, 1 day or 1 week across a range of nominal fluoxetine concentrations (10 ng/L, 100 ng/L and 1000 ng/L) and the chromatophore index or carapace percentage ‘darkness’ was recorded following 30 min on white and black substrates. These experiments were repeated three times using different specimens. Animals became significantly darker (~20%) on darker background and lighter on light backgrounds as one might expect. However, time periods over which the animals were recorded had a significant impact on the colouration suggesting habituation to laboratory conditions. Fluoxetine exposure came up as a significant factor in two of the three trials for the chromatophore index but the results was inconsistent between trials. There was a high degree of correlation between the chromatophore index and the percentage darkness analyses however, there was no significant effects for fluoxetine exposure with the percentage darkness data. We conclude that the effects on antidepressants on colour change remain inconclusive from these experiments and we discuss potential areas to improve the repeatability of the experiments.

2018 ◽  
Vol 35 (1-2) ◽  
pp. 189-223
Author(s):  
Petra Kieffer-Pülz

The present contribution suggests the common authorship of three P?li commentaries of the twelfth/thirteenth centuries CE, namely the Vinayavinicchaya??k? called Vinayas?ratthasand?pan? (less probably Vinayatthas?rasand?pan?), the Uttaravinicchaya??k? called L?natthappak?san?, and the Saccasa?khepa??k? called S?ratthas?lin?. The information collected from these three commentaries themselves and from P?li literary histories concerning these three texts leads to the second quarter of the thirteenth century CE as the period of their origination. The data from parallel texts explicitly stated to having been written by V?cissara Thera in the texts themselves render it possible to establish with a high degree of probability V?cissara Thera as their author.


1973 ◽  
Vol 33 (3) ◽  
pp. 891-900 ◽  
Author(s):  
Itai Zak

The main problem posed in this study is: What are the content and structure of Jewish and American identity? The Jewish-American Identity Scale, which was adapted and refined for this study, was administered in 1971 to four samples, totaling 1006 Jewish-American college students from various parts of the United States. Initially, factor analysis was applied to the separate samples. Intersample comparisons of factor structures indicated a high degree of congruency; consequently, the samples were combined for subsequent analyses. Factor analysis of the test scores demonstrated that most of the common factor variance was appropriated by two relatively orthogonal factors. Items dealing with American identity and those dealing with Jewish identity had medium to high loadings on the two respective factors. These findings supported the hypothesis of the duality and the orthogonality of dimensions of Jewish and American identity, and cast doubt on the notion forwarded by some researchers that Jewish-American identity forms a bipolar continuum.


Author(s):  
José Luis Varela ◽  
Cristhian Ronald Lucas-Pilozo ◽  
Manuel María González-Duarte

The diet and the feeding habits of the common dolphinfish (Coryphaena hippurus) in the Pacific coast of Ecuador was assessed by examining 320 stomachs of individuals ranging from 51 to 149 cm in total length. Fish was the predominant prey group in the diet (Alimentary Index, %AI = 95.39) followed by cephalopods (%AI = 4.13) and crustaceans (%AI = 0.48). Among the 17 prey items that make up the dolphinfish diet, the Exocoetidae family was the most important prey (%AI = 57.13), Dosidicus gigas being the most abundant invertebrate species (%AI = 7.65). Feeding patterns were evaluated using the graphing method of Amundsen, which suggested that this species shows a varying degree of specialization on different prey taxa. Thus, while some species were unimportant and rare (Hippocampus hippocampus, Lagocephalus lagocephalus, Gobiidae and Argonauta sp.), several dolphinfishes showed a high degree of specialization on Scombridae, Pleuroncodes planipes, Portunus xantusii and Opisthonema libertate. Size-related and temporal shifts in dietary composition were investigated by PERMANOVA analysis, which showed wide variations among size classes and periods of capture. The results of this study indicate that the common dolphinfish is an opportunistic feeder, which is capable of consuming a wide variety of schooling epipelagic organisms.


2017 ◽  
Vol 9 (8) ◽  
pp. 162
Author(s):  
Youngho Chang ◽  
Zheng Fang ◽  
Shigeyuki Hamori

Commodity prices have fluctuated sharply and Brent oil has been considered the most volatile commodity in price. This paper aims to reveal the true characteristics of the price volatility of six commodities, namely, Brent oil, gold, silver, wheat, corn and soybean and to verify the existence of a long-run relationship and causation among each pair of commodity prices. It finds that there has been persistent volatility in prices of all six commodities from 1986 to 2010. Contrary to the common belief, however, Brent oil appears not to be the most volatile in price. Rather the prices of precious metals and agricultural commodities have been more volatile than Brent oil for some time periods. It also finds that there has been a long-run relationship between the prices of Brent oil and soybean, of Brent oil and wheat, and a bilateral causality relationship between them, which implies that there has been a simultaneous impact on the price trajectories of these commodities.


1969 ◽  
Vol 1 (2) ◽  
pp. 211-237 ◽  
Author(s):  
R. E. Miles

This is the first part of a three part work, the common setting being Ed, Euclidean space of d dimensions. Many random physical phenomena, often in the form of structures, admit models which are assemblages of random s-flats in Ed. Indeed, taking s = 0, any n-sample from a d-dimensional distribution may of course be so regarded! For static phenomena generally 0 ≦ s < d ≦ 3, while 4 is to be substituted for 3 if time variation is allowed. By postulating a high degree of stochastic independence and uniformity, a variety of “simple” models is defined. However, their investigation poses problems in geometrical probability of a wide range of difficulty; the solutions of many of which are still far from complete.


2015 ◽  
Vol 212 ◽  
pp. 163-177 ◽  
Author(s):  
Olivier Christiaens ◽  
Daan Delbare ◽  
Christophe Van Neste ◽  
Kaat Cappelle ◽  
Na Yu ◽  
...  

1930 ◽  
Vol 52 (1) ◽  
pp. 95-102 ◽  
Author(s):  
F. P. Gay ◽  
A. R. Clark

The experimental work herein reported tends to justify our hypothesis recently expressed, that the common failure of antibacterial serums to combat active infections when passively transferred to a normal animal, is due not so much to a lack of suitable or sufficient antibodies as to absence of cell preparation or mobilization in the recipient. In the case of experimental streptococcus empyema in the rabbit the course of the ordinarily fatal infection is in no wise affected by the transfer of the pleural fluid containing large numbers of mononuclear cells derived from an animal that is itself protected as a result of a non-specific irritation. The serum of a rabbit highly immunized against the streptococcus and containing antibodies for it, produces relatively slight effect in prevention or cure. In contrast to this the pleural exudate, either acute (polymorphonuclear) or subacute (mononuclear), produced in an actively immunized animal does protect passively to a considerable degree. In a similar fashion normal exudate cells of either type in combination with the relatively ineffective antiserum give a high degree of protection. It remains for further analysis to determine whether this form of passive immunity by antiserum enhanced by the addition of cells depends on the vital properties of the cells transferred or on their stimulation to cell mobilization in the recipient. And furthermore the extent to which this enhanced passive immunity may be effective in cure, and whether the cure is applicable to local or to both local and generalized infection remains to be seen.


2013 ◽  
Vol 161 (2) ◽  
pp. 447-458 ◽  
Author(s):  
Stefan Reiser ◽  
Jens-Peter Herrmann ◽  
Thomas Neudecker ◽  
Axel Temming

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