The effects of hatchery and wild ancestry and experience on the relative ability of steelhead trout fry (Oncorhynchus mykiss) to avoid a benthic predator

1995 ◽  
Vol 52 (11) ◽  
pp. 2476-2482 ◽  
Author(s):  
Barry A. Berejikian
Keyword(s):  
Oncorhynchus Mykiss ◽  
Predator Avoidance ◽  
Laboratory Experiments ◽  
Test Period ◽  
Natural Environments ◽  
Steelhead Trout ◽  
Visual Exposure ◽  
Natural Stream ◽  
Relative Ability ◽  
Better Than

Differences in selection regimes between hatchery and natural environments and environmental stimuli, among other factors, have the potential to cause differences in predator avoidance ability between hatchery and wild steelhead trout fry (Oncorhynchus mykiss). In two separate laboratory experiments, fry raised from eggs of wild Quinault River steelhead trout survived predation by prickly sculpin (Cottus asper) significantly better than size-matched offspring of a locally derived hatchery population, which were reared under similar conditions. Wild fry also survived predation better than hatchery fry in natural stream enclosures over a 3-day test period. Experience, in the form of 50-min visual exposure to sculpin predation on "sacrificial" steelhead trout, improved the ability of fry from both populations to avoid predation by sculpin. Wild-experienced fry were eaten in the fewest number of trials followed by wild-naive, hatchery-experienced, and hatchery-naive fry. The results of this study are consistent with the hypothesis that innate predator avoidance ability has been negatively altered through domestication and that attempts to condition hatchery-reared steelhead to avoid predators may be limited for domesticated populations.

Development and Testing of an Unmanned Aerial Vehicle for Large Scale Particle Image Velocimetry

2014 ◽  
Author(s):  
Christopher Pagano ◽  
Flavia Tauro ◽  
Salvatore Grimaldi ◽  
Maurizio Porfiri
Keyword(s):  
Particle Image Velocimetry ◽  
Large Scale ◽  
Field Experiments ◽  
Particle Image ◽  
Low Cost ◽  
Surface Flow ◽  
Natural Environments ◽  
Natural Stream ◽  
Image Velocimetry ◽  
Scale Particle

Large scale particle image velocimetry (LSPIV) is a nonintrusive environmental monitoring methodology that allows for continuous characterization of surface flows in natural catchments. Despite its promise, the implementation of LSPIV in natural environments is limited to areas accessible to human operators. In this work, we propose a novel experimental configuration that allows for unsupervised LSPIV over large water bodies. Specifically, we design, develop, and characterize a lightweight, low cost, and stable quadricopter hosting a digital acquisition system. An active gimbal maintains the camera lens orthogonal to the water surface, thus preventing severe image distortions. Field experiments are performed to characterize the vehicle and assess the feasibility of the approach. We demonstrate that the quadricopter can hover above an area of 1×1m2 for 4–5 minutes with a payload of 500g. Further, LSPIV measurements on a natural stream confirm that the methodology can be reliably used for surface flow studies.

On Knowing Books by Their Colors

1979 ◽  
Vol 48 (2) ◽  
pp. 479-488 ◽  
Author(s):  
Robert M. Boynton ◽  
Stanley Dolensky
Keyword(s):  
Color Vision ◽  
Recognition Task ◽  
Color Blindness ◽  
Test Period ◽  
Normal Color Vision ◽  
Abstract Stimulus ◽  
Color Cues ◽  
Stimulus Materials ◽  
Search And Recognition ◽  
Better Than

In a search and recognition task utilizing real-world objects, the usefulness of color cues is observed to depend upon the availability of alphanumeric information. Following a 45-sec. inspection of a randomly selected collection of 17 books, spread on a table with their titles exposed, subjects were asked to identify as many of these as possible during a test period beginning 3 min. later in which 17 decoys were also present. Some subjects wore glasses with red filters during the test and inspection periods. The color blindness thereby introduced did not impair their performance in comparison with control subjects who were able to utilize normal color vision. Moreover, the introduction of color during the test period impaired the performance of subjects who had been deprived of color cues during inspection. It was concluded that subjects paid attention mostly to book titles and for that reason did not use other cues, including color, to much advantage. In a second experiment, where titles were obscured, subjects with normal color vision performed much better than those who were made color blind during the inspection or test periods. The results of both experiments are generally consistent with predictions based on experiments which have used abstract stimulus materials.

scholarly journals Uplift Resistance Capacity of Anchor Piles used in Marine Aquaculture

2021 ◽  
Author(s):  
Fukun Gui ◽  
Jianqiao Kong ◽  
Dejun Feng ◽  
Xiaoyu Qu ◽  
Fang Zhu ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Failure Load ◽  
Lateral Displacement ◽  
Single Pile ◽  
Initial Tension ◽  
Marine Aquaculture ◽  
Pile Diameter ◽  
Single Piles ◽  
Uplift Resistance ◽  
Better Than

Abstract Anchor piles are widely used in marine aquaculture, and their uplift resistance capacity largely determines their safety, especially in harsh ocean environments. However, a practical guide on its design and installation is wanting. Laboratory experiments were conducted to investigate the effect of the initial tension angle, pile diameter, embedded depth, and pile configuration on the uplift resistance capacity of anchor piles for marine aquaculture under oblique loads. The results show that increasing the initial tension angle of circular and square single piles can significantly improve the uplift resistance capacity. The failure load of the square single pile was slightly higher than that of the circular single pile. Increasing the pile diameter can effectively improve the failure load and delay the development speed of the pile top displacement. Increasing the embedded depth can effectively improve the failure load and increase the lateral displacement of the pile top. The uplift resistance capacity of the dual anchor piles was better than that of the single anchor piles. The layout configuration has little effect on the failure load, but has a large effect on the displacement development.

scholarly journals Sex overrides mutation in Escherichia coli colonizing the gut

2018 ◽  
Author(s):  
N. Frazão ◽  
A. Sousa ◽  
M. Lässig ◽  
I. Gordo
Keyword(s):  
Escherichia Coli ◽  
Experimental Evolution ◽  
Temporal Pattern ◽  
Driving Force ◽  
Laboratory Experiments ◽  
Rapid Evolution ◽  
Point Mutations ◽  
Natural Environments ◽  
E Coli ◽  
Accelerate Evolution

AbstractBacteria evolve by mutation accumulation in laboratory experiments, but the tempo and mode of evolution in natural environments are largely unknown. Here we show, by experimental evolution of E. coli in the mouse gut, that the ecology of the gut controls bacterial evolution. If a resident E. coli strain is present in the gut, an invading strain evolves by rapid horizontal gene transfer; this mode precedes and outweighs evolution by point mutations. An epidemic infection by two phages drives gene uptake and produces multiple co-existing lineages of phage-carrying (lysogenic) bacteria. A minimal dynamical model explains the temporal pattern of phage epidemics and their complex evolutionary outcome as generic effects of phage-mediated selection. We conclude that phages are an important eco-evolutionary driving force – they accelerate evolution and promote genetic diversity of bacteria.One Sentence SummaryBacteriophages drive rapid evolution in the gut.

scholarly journals Interaction of rat glutathione S-transferases 7-7 and 8-8 with γ-glutamyl- or glycyl-modified glutathione analogues

1989 ◽  
Vol 264 (3) ◽  
pp. 759-764 ◽  
Author(s):  
A E P Adang ◽  
D J Meyer ◽  
J Brussee ◽  
A Van der Gen ◽  
B Ketterer ◽  
...  
Keyword(s):  
Active Sites ◽  
Ethacrynic Acid ◽  
Acceptor Substrate ◽  
Gamma Glutamyl ◽  
Relative Ability ◽  
Glutathione S Transferases ◽  
Better Than

Analogues of GSH in which either the gamma-glutamyl or the glycyl moiety is modified were synthesized and tested as both substrates for and inhibitors of glutathione S-transferases (GSTs) 7-7 and 8-8. Acceptor substrates for GST 7-7 were 1-chloro-2,4-dinitrobenzene (CDNB) and ethacrynic acid (ETA) and for GST 8-8 CDNB, ETA and 4-hydroxynon-trans-2-enal (HNE). The relative ability of each combination of enzyme and GSH analogue to catalyse the conjugation of all acceptor substrates was similar with the exception of the combination of GST 7-7 and gamma-L-Glu-L-Cys-L-Asp, which used CDNB but not ETA as acceptor substrate. In general, GST 7-7 was better than GST 8-8 in utilizing these analogues as substrates, and glycyl analogues were better than gamma-glutamyl analogues as both substrates and inhibitors. These results are compared with those obtained earlier with GSH analogues and GST isoenzymes 1-1, 2-2, 3-3 and 4-4 [Adang, Brussee, Meyer, Coles, Ketterer, van der Gen & Mulder (1988) Biochem. J. 255, 721-724] and the implications with respect to the nature of their active sites are discussed.

Sign in / Sign up

Export Citation Format

Share Document