An Evaluation of the Stereocinematographic Method to Estimate Fish Swimming Speed

1992 ◽  
Vol 49 (3) ◽  
pp. 523-531 ◽  
Author(s):  
Daniel Boisclair
Keyword(s):  
Coordinate System ◽  
Sample Size ◽  
Swimming Speed ◽  
Fish Swimming ◽  
Individual Fish ◽  
Precision And Accuracy ◽  
Over Time

I evaluated the precision and accuracy of the stereocinematographic (SCG) method for estimating fish swimming speed. The SCG method implements the differences in images recorded by two cameras to determine the position of a target in an x, y, z, coordinate system. Movements and speeds were determined using variations in the position of the targets over time. Movements of rulers [Formula: see text] estimated in the laboratory did not differ significantly from measured values. The accuracy of the SCG method in the field was assessed by comparing simultaneous estimates of the speed of the head and of the tail of individual fish observed in in situ enclosures. Differences between these descriptors of fish swimming were always < 2 body lengths (bl)∙s−1 and, on average, did not differ significantly from 0. Swimming speeds [Formula: see text] ranged from 0.6 to 20.7 cm∙s−1 (0.1–3.8 bl∙s−1). Speed variations between two consecutive 1-s intervals ranged from −23.9 cm∙s−1 (deceleration) to 23.6 cm∙s−1 (acceleration). Positioning fish at 1- to 6-s intervals tended to decrease the variance of swimming speed estimates. A sample size of 100–150 speeds per hour was sufficient to accurately describe fish swimming in an in situ enclosure.

Can stationary bottom split-beam hydroacoustics be used to measure fish swimming speed in situ?

2000 ◽  
Vol 45 (1) ◽  
pp. 31-41 ◽  
Author(s):  
Fredrik Arrhenius ◽  
Bastiaan J.A.M. Benneheij ◽  
Lars G. Rudstam ◽  
Daniel Boisclair
Keyword(s):  
Swimming Speed ◽  
Fish Swimming

scholarly journals Influence of Hydrogeochemistry on Tunnel Drainage in Evaporitic Formations: El Regajal Tunnel Case Study (Aranjuez, Spain)

2021 ◽  
Vol 13 (3) ◽  
pp. 1505
Author(s):  
Ignacio Menéndez Pidal ◽  
Jose Antonio Mancebo Piqueras ◽  
Eugenio Sanz Pérez ◽  
Clemente Sáenz Sanz
Keyword(s):  
High Speed ◽  
Civil Engineering ◽  
Saturation Index ◽  
The Subject ◽  
Under Construction ◽  
Underground Flow ◽  
Very High ◽  
Over Time

Many of the large number of underground works constructed or under construction in recent years are in unfavorable terrains facing unusual situations and construction conditions. This is the case of the subject under study in this paper: a tunnel excavated in evaporitic rocks that experienced significant karstification problems very quickly over time. As a result of this situation, the causes that may underlie this rapid karstification are investigated and a novel methodology is presented in civil engineering where the use of saturation indices for the different mineral specimens present has been crucial. The drainage of the rock massif of El Regajal (Madrid-Toledo, Spain, in the Madrid-Valencia high-speed train line) was studied and permitted the in-situ study of the hydrogeochemical evolution of water flow in the Miocene evaporitic materials of the Tajo Basin as a full-scale testing laboratory, that are conforms as a whole, a single aquifer. The work provides a novel methodology based on the calculation of activities through the hydrogeochemical study of water samples in different piezometers, estimating the saturation index of different saline materials and the dissolution capacity of the brine, which is surprisingly very high despite the high electrical conductivity. The circulating brine appears unsaturated with respect to thenardite, mirabilite, epsomite, glauberite, and halite. The alteration of the underground flow and the consequent renewal of the water of the aquifer by the infiltration water of rain and irrigation is the cause of the hydrogeochemical imbalance and the modification of the characteristics of the massif. These modifications include very important loss of material by dissolution, altering the resistance of the terrain and the increase of the porosity. Simultaneously, different expansive and recrystallization processes that decrease the porosity of the massif were identified in the present work. The hydrogeochemical study allows the evolution of these phenomena to be followed over time, and this, in turn, may facilitate the implementation of preventive works in civil engineering.

scholarly journals In Situ Production of Zoospores by Five Species of Phytophthora in Aqueous Environments for Use as Inocula

Plant Disease ◽  
2014 ◽  
Vol 98 (4) ◽  
pp. 551-558 ◽  
Author(s):  
G. A. Ridge ◽  
S. N. Jeffers ◽  
W. C. Bridges ◽  
S. A. White
Keyword(s):  
Laboratory Experiment ◽  
Constructed Wetlands ◽  
Aquatic Plant ◽  
Phytophthora Cinnamomi ◽  
Soil Extract ◽  
Greenhouse Experiment ◽  
Zoospore Release ◽  
Aqueous Environments ◽  
Over Time

The goal of this study was to develop a procedure that could be used to evaluate the potential susceptibility of aquatic plants used in constructed wetlands to species of Phytophthora commonly found in nurseries. V8 agar plugs from actively growing cultures of three or four isolates of Phytophthora cinnamomi, P. citrophthora, P. cryptogea, P. nicotianae, and P. palmivora were used to produce inocula. In a laboratory experiment, plugs were placed in plastic cups and covered with 1.5% nonsterile soil extract solution (SES) for 29 days, and zoospore presence and activity in the solution were monitored at 2- or 3-day intervals with a rhododendron leaf disk baiting bioassay. In a greenhouse experiment, plugs of each species of Phytophthora were placed in plastic pots and covered with either SES or Milli-Q water for 13 days during both summer and winter months, and zoospore presence in the solutions were monitored at 3-day intervals with the baiting bioassay and by filtration. Zoospores were present in solutions throughout the 29-day and 13-day experimental periods but consistency of zoospore release varied by species. In the laboratory experiment, colonization of leaf baits decreased over time for some species and often varied among isolates within a species. In the greenhouse experiment, bait colonization decreased over time in both summer and winter, varied among species of Phytophthora in the winter, and was better in Milli-Q water. Zoospore densities in solutions were greater in the summer than in the winter. Decreased zoospore activities for some species of Phytophthora were associated with prolonged temperatures below 13 or above 30°C in the greenhouse. Zoospores from plugs were released consistently in aqueous solutions for at least 13 days. This procedure can be used to provide in situ inocula for the five species of Phytophthora used in this study so that aquatic plant species can be evaluated for potential susceptibility.

scholarly journals Identifying Spatial and Temporal Variations in Concrete Bridges with Ground Penetrating Radar Attributes

2021 ◽  
Vol 13 (9) ◽  
pp. 1846
Author(s):  
Vivek Kumar ◽  
Isabel M. Morris ◽  
Santiago A. Lopez ◽  
Branko Glisic
Keyword(s):  
Compressive Strength ◽  
Ground Penetrating Radar ◽  
Material Properties ◽  
Temporal Variations ◽  
Concrete Bridges ◽  
Spatial And Temporal Variation ◽  
Reflected Waves ◽  
Ground Penetrating ◽  
Over Time

Estimating variations in material properties over space and time is essential for the purposes of structural health monitoring (SHM), mandated inspection, and insurance of civil infrastructure. Properties such as compressive strength evolve over time and are reflective of the overall condition of the aging infrastructure. Concrete structures pose an additional challenge due to the inherent spatial variability of material properties over large length scales. In recent years, nondestructive approaches such as rebound hammer and ultrasonic velocity have been used to determine the in situ material properties of concrete with a focus on the compressive strength. However, these methods require personnel expertise, careful data collection, and high investment. This paper presents a novel approach using ground penetrating radar (GPR) to estimate the variability of in situ material properties over time and space for assessment of concrete bridges. The results show that attributes (or features) of the GPR data such as raw average amplitudes can be used to identify differences in compressive strength across the deck of a concrete bridge. Attributes such as instantaneous amplitudes and intensity of reflected waves are useful in predicting the material properties such as compressive strength, porosity, and density. For compressive strength, one alternative approach of the Maturity Index (MI) was used to estimate the present values and compare with GPR estimated values. The results show that GPR attributes could be successfully used for identifying spatial and temporal variation of concrete properties. Finally, discussions are presented regarding their suitability and limitations for field applications.

Analyses of Echo-traces of Individual Fish Obtained in situ by Dual-beam Method.

1993 ◽  
Vol 59 (6) ◽  
pp. 943-950 ◽  
Author(s):  
Yoichi Miyanohana ◽  
Koichi Sawada ◽  
Yoshimi Takao ◽  
Masahiko Furusawa
Keyword(s):  
Individual Fish ◽  
Dual Beam ◽  
Beam Method

Effect of physical processing on in situ degradation of barley in the caecum of ponies

1998 ◽  
Vol 1998 ◽  
pp. 127-127
Author(s):  
B M L McLean ◽  
J J Hyslop ◽  
A C Longland ◽  
D Cuddeford
Keyword(s):  
Sample Size ◽  
Dry Matter ◽  
Cereal Grains ◽  
Processing Methods ◽  
Grass Hay ◽  
Physical Processing ◽  
In Situ Degradation ◽  
Ad Libitum ◽  
Fixed Times

Cereal grains are often subjected to physical processing before being fed to equids. However, little information is available on how physical processing of cereals affects degradation dynamics in equids. This experiment examines the effect of two physical processing methods (micronisation and extrusion) on in situ degradation of barley in the caecum of poniesThree caecally fistulated mature Welsh-cross pony geldings (approx. LW 270kg) were offered ad libitum grass hay plus minerals. Incubation bags (monofilament polyester 6.5 x 20cm, 41μm pores, 16mg/cm2 sample size) containing either unprocessed barley (UB), micronised barley (MB) or extruded barley (EB) were incubated in the caecum for fixed times according to both a forward (0, 2, 4, 6, 12, 8, 24, 48h) and reverse (48, 24, 8, 4, 12, 6, 2, 0h) incubation sequence. For each feedstuff residues from each time were bulked within pony and across incubation sequence for subsequent analysis of dry matter (DM) and starch (STC). Degradation profiles were fitted to the DM and STC disappearance data according to Ørskov and McDonald (1979).

THE EFFECT OF SOLID AND POROUS CHANNEL WALLS ON STEADY SWIMMING OF STEELHEAD TROUT ONCORHYNCHUS MYKISS

1993 ◽  
Vol 178 (1) ◽  
pp. 97-108 ◽  
Author(s):  
P. W. Webb
Keyword(s):  
Swimming Speed ◽  
Swimming Performance ◽  
Beat Frequency ◽  
Regression Coefficients ◽  
Steelhead Trout ◽  
Wall Effects ◽  
Fish Swimming ◽  
Wide Channel ◽  
Solid Walls ◽  
Tail Beat

Kinematics and steady swimming performance were recorded for steelhead trout (approximately 12.2 cm in total length) swimming in channels 4.5, 3 and 1.6 cm wide in the centre of a flume 15 cm wide. Channel walls were solid or porous. Tail-beat depth and the length of the propulsive wave were not affected by spacing of either solid or porous walls. The product of tail-beat frequency, F, and amplitude, H, was related to swimming speed, u, and to harmonic mean distance of the tail from the wall, z. For solid walls: FH = 1.01(+/−0.31)u0.67(+/−0.09)z(0.12+/−0.02) and for grid walls: FH = 0.873(+/−0.302)u0.74(+/−0.08)z0.064(+/−0.024), where +/−2 s.e. are shown for regression coefficients. Thus, rates of working were smaller for fish swimming between solid walls, but the reduction due to wall effects decreased with increasing swimming speed. Porous grid walls had less effect on kinematics, except at low swimming speeds. Spacing of solid walls did not affect maximum tail-beat frequency, but maximum tail-beat amplitude decreased with smaller wall widths. Maximum tail-beat amplitude similarly decreased with spacing between grid walls, but maximum tail-beat frequency increased. Walls also reduced maximum swimming speed. Wall effects have not been adequately taken into account in most studies of fish swimming in flumes and fish wheels.

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