scholarly journals The average three-dimensional target strength of fish by spheroid model for sonar surveys

2009 ◽  
Vol 66 (6) ◽  
pp. 1176-1183 ◽  
Author(s):  
Yong Tang ◽  
Yasushi Nishimori ◽  
Masahiko Furusawa
Keyword(s):  
Three Dimensional ◽  
Prolate Spheroid ◽  
Target Strength ◽  
Fish Length ◽  
Fish Schools ◽  
Fluid Boundary ◽  
The Difference ◽  
Yaw Angle ◽  
The Relationship ◽  
Actual Orientation

Abstract Tang, Y., Nishimori, Y., and Furusawa, M. 2009. The average three-dimensional target strength of fish by spheroid model for sonar surveys. – ICES Journal of Marine Science, 66: 1176–1183. When surveying fish schools by sonar, the fish are insonified from various directions. Because the fish target strength (TS) has three-dimensional directivity, according to its orientation relative to the sonar beam, the TS must be appropriately averaged. By connecting the geometries of the sonar beam and the fish body, the relationship between the apparent orientation of fish, as viewed by the sonar, and the actual orientation in space is derived. Using this relationship, equations for calculating the three-dimensional-averaged TS (<TS>3D) are presented. A prolate-spheroid, modal-series, scattering model is then used to determine the characteristics of <TS>3D against various parameters, such as fish attitudes, fish length, sonar frequency, and method of beam scanning. The model is evaluated with two boundary conditions at the spheroid surface: a gas-fluid boundary relevant to fish with a swimbladder, and a fluid-fluid boundary relevant to fish without a swimbladder. The results reveal that <TS>3D varies greatly with the horizontal aspect (yaw angle), but only slightly with the vertical aspect (pitch angle) of the fish. The difference in <TS>3D between the side-on aspect and the end-on (head or tail) aspect increases with the ratio of the fish length to the acoustic wavelength.

scholarly journals Three-dimensional analysis of acetabular cup orientation and an evaluation of the relationship with pelvic sagittal parameters

2019 ◽  
Vol 27 (2) ◽  
pp. 230949901986122
Author(s):  
Ali Sahin ◽  
Mehmet Emin Simsek ◽  
Safa Gursoy ◽  
Mustafa Akkaya ◽  
Cetin Isik ◽  
...  
Keyword(s):  
Pelvic Tilt ◽  
Three Dimensional ◽  
Preoperative Assessment ◽  
Statistical Correlation ◽  
Acetabular Cup ◽  
Pelvic Parameters ◽  
Sagittal Parameters ◽  
The Mean ◽  
The Difference ◽  
The Relationship

Background: This study aimed to evaluate the effect of total hip arthroplasty (THA) on sagittal pelvic parameters and to evaluate the effect of sagittal pelvic parameters on acetabular cup orientation. Methods: The study included 86 patients who underwent THA for a diagnosis of unilateral coxarthrosis between 2011 and 2015. Measurements were taken of the preoperative and postoperative acetabular cup inclination (ACI), anteversion, and sagittal pelvic parameters. The effect of THA on sagittal pelvic parameters and the effects of the sagittal pelvic parameters on acetabular cup orientation were investigated. Results: The sagittal pelvic tilt values calculated were mean 9.7° ± 6.3° (2°; 23°) preoperatively and 11.0° ± 6.1° (2°; 25°) postoperatively. The increase in postoperative pelvic incidence (PI) values was determined to be statistically significant ( p < 0.05). The preoperative PI values had no significant effect on ACI, but in cases with high preoperative PI values, a tendency to high anteversion values was determined. The mean inclination values were found to be 40.2° ± 11.0° in the low PI group, 41.7° ± 7.4° in the normal PI group, and 44.1° ± 8.3° in the high PI group. As no increase in inclination values was observed with an increase in PI values, no statistical correlation was determined ( p = 0.343). Average of anteversion values in the low PI group was 9.2° ± 13.7°, in the normal PI group 19.3° ± 10.5°, and in the high PI group 21.1° ± 12.5°. The difference between the groups was statistically significant ( p = 0.001). Conclusion: Evaluating the results of this study, it can be concluded that varying PI values do affect the acetabular cup anterversion in THA. So, preoperative assessment of PI values is important in preventing postoperative acetabular cup malposition.

Relationship Between Weightbearing Ankle Dorsiflexion Passive Range of Motion and Ankle Kinematics During Gait

2017 ◽  
Vol 107 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Min-Hyeok Kang ◽  
Jae-Seop Oh
Keyword(s):  
Range Of Motion ◽  
Three Dimensional ◽  
Knee Extension ◽  
Ankle Dorsiflexion ◽  
Physically Active ◽  
Ankle Kinematics ◽  
The Difference ◽  
Analysis System ◽  
The Relationship ◽  
Paired T Test

Background: Measurement of weightbearing ankle dorsiflexion (DF) passive range of motion (PROM) has been suggested as a way to estimate ankle kinematics during gait; however, no previous study has demonstrated the relationship between ankle DF during gait and ankle DF PROM with knee extension. We examine the relationship between maximum ankle DF during gait and nonweightbearing and weightbearing ankle DF PROM with knee extension. Methods: Forty physically active individuals (mean ± SD age, 21.63 ± 1.73 years) participated in this study. Ankle DF PROM with knee extension was measured in the nonweightbearing and weightbearing conditions; maximum ankle DF during gait was assessed using a three-dimensional motion analysis system. The relationship between each variable was calculated using the Pearson product moment correlation coefficient, and the difference in ankle DF PROM between the nonweightbearing and weightbearing conditions was analyzed using a paired t test. Results: The weightbearing measurement (r = 0.521; P &lt; .001) for ankle DF PROM showed a greater correlation with maximum ankle DF during gait than did the nonweightbearing measurement (r = 0.245; P = .029). Ankle DF PROM was significantly greater in the weightbearing than in the nonweightbearing condition (P &lt; .001) despite a significant correlation between the two measurements (r = 0.402; P &lt; .001). Conclusions: These findings indicate that nonweightbearing and weightbearing measurements of ankle DF PROM with knee extension should not be used interchangeably and that weightbearing ankle DF PROM with the knee extended is more appropriate for estimating ankle DF during gait.

scholarly journals Studies on crystal structures, active-centre geometry and depurinating mechanism of two ribosome-inactivating proteins

1995 ◽  
Vol 309 (1) ◽  
pp. 285-298 ◽  
Author(s):  
Q Huang ◽  
S Liu ◽  
Y Tang ◽  
S Jin ◽  
Y Wang
Keyword(s):  
Three Dimensional ◽  
Active Centre ◽  
Ribosome Inactivating Proteins ◽  
Aromatic Stacking ◽  
Replacement Method ◽  
Isomorphous Replacement ◽  
Molecular Replacement Method ◽  
The Difference ◽  
Related Proteins ◽  
The Relationship

Two ribosome-inactivating proteins, trichosanthin and alpha-momorcharin, have been studied in the forms of complexes with ATP or formycin, by an X-ray-crystallographic method at 1.6-2.0 A (0.16-0.20 nm) resolution. The native alpha-momorcharin had been studied at 2.2 A resolution. Structures of trichosanthin were determined by a multiple isomorphous replacement method. Structures of alpha-momorcharin were determined by a molecular replacement method using refined trichosanthin as the searching model. Small ligands in all these complexes have been recognized and built on the difference in electron density. All these structures have been refined to achieve good results, both in terms of crystallography and of ideal geometry. These two proteins show considerable similarity in their three-dimensional folding and to that of related proteins. On the basis of these structures, detailed geometries of the active centres of these two proteins are described and are compared with those of related proteins. In all complexes the interactions between ligand atoms and protein atoms, including hydrophobic forces, aromatic stacking interactions and hydrogen bonds, are found to be specific towards the adenine base. The relationship between the sequence conservation of ribosome-inactivating proteins and their active-centre geometry was analysed. A depurinating mechanism of ribosome-inactivating proteins is proposed on the basis of these results. The N-7 atom of the substrate base group is proposed to be protonated by an acidic residue in the active centre.

scholarly journals Estimation of the Coefficients of the Equation of Acoustic Target Strength Based on the Morphology of Coregonus migratorius (Georgi, 1775) Swim Bladder

2020 ◽  
Vol 15 (1) ◽  
pp. 89-98
Author(s):  
P. N. Anoshko ◽  
M. M. Makarov ◽  
S. B. Popov ◽  
A. I. Degtev ◽  
N. N. Denikina ◽  
...  
Keyword(s):  
Acoustic Scattering ◽  
Morphological Characteristics ◽  
Prolate Spheroid ◽  
The Body ◽  
Target Strength ◽  
Fish Length ◽  
Swim Bladder ◽  
Experimental Conditions ◽  
Scattering Model ◽  
Acoustic Target

Aim. The aim of the study was to estimate the coefficients of the equation TSmax=f(SL) considering the characteristics of an acoustic scattering model based on the morphological characteristics of the swim bladder of the Coregonus migratorius (Georgi, 1775). Material and Methods. Ninety‐nine living specimens of C. migratorius served as the study material. For each specimen, the target strength in the cage was measured using an Kongsberg Simrad EY500 echo sounder and the morphology of the swim bladder was studied. Measurements, analysis of images and data were conducted using Image Pro 6.0. Excel and SciLab software resources. Results. We determined the main morphological characteristics of the swim bladder in C. migratorius as well as the correspondence of its dimensions and proportions in relation to the length of the fish’s body. The coefficients of the equation TS=20log(SL)‐60, calculated on the results of the acoustic scattering model of a prolate spheroid, agree well with the coefficients calculated from maximum values obtained in the cage experiment. During the conversion of the coefficients relating to the allometric changes in the length of the swim bladder relative to fish length, the equation TS=23.2log(SL)‐64.4 was obtained. A comparative analysis of the available equations of the target strength for C. migratorius with those obtained in the study was undertaken. Conclusion. The equation obtained on the model of the swim bladder as a prolate spheroid adequately describes the dependence of the maximum values of the target strength on the body length of the C. migratorius and confirms the previously obtained dependence by maximum values of TS in the cage experimental conditions and can serve as a basis for further theoretical studies.

scholarly journals Progress in determining southern blue whiting (Micromesistius australis) target strength: results of swimbladder modelling

2006 ◽  
Vol 63 (5) ◽  
pp. 952-955 ◽  
Author(s):  
Adam J. Dunford ◽  
Gavin J. Macaulay
Keyword(s):  
Gadus Morhua ◽  
Stock Assessment ◽  
Laser Scanner ◽  
Fork Length ◽  
Sensitivity Analyses ◽  
Target Strength ◽  
Fish Length ◽  
Angle Distribution ◽  
Blue Whiting ◽  
The Relationship

Abstract Southern blue whiting target strength (TS) results from Kirchhoff modelling of swimbladder casts scanned using a hand-held 3D laser scanner are presented. The data are compared with the relationship between TS and fish length used for New Zealand stock-assessment surveys; TS = 21.8 log10(fork length) − 72.8, at 38 kHz. This relationship has its origins in the relationship used for blue whiting (Micromesistius poutassou) in the northern hemisphere, and is based on measurements on juvenile cod (Gadus morhua). The results indicate that the blue whiting relationship is not appropriate for southern blue whiting, and suggest a much steeper slope, with TS = 38 log10(fork length) − 97, at 38 kHz. Sensitivity analyses indicate that further investigations of swimbladder tilt-angle distribution and swimbladder volume are unlikely to provide evidence to support the use of the blue whiting relationship for southern blue whiting.

scholarly journals The analysis of echotrace obtained by a split-beam echosounder to observe the tilt-angle dependence of fish target strength in situ

2009 ◽  
Vol 67 (2) ◽  
pp. 215-230 ◽  
Author(s):  
Masahiko Furusawa ◽  
Kazuo Amakasu
Keyword(s):  
Theoretical Model ◽  
Tilt Angle ◽  
Three Dimensional ◽  
Prolate Spheroid ◽  
Target Strength ◽  
Accurate Information ◽  
Careful Selection ◽  
Angle Dependence ◽  
Selection Of

Abstract Furusawa, M., and Amakusu, K. 2010. The analysis of echotrace obtained by a split-beam echosounder to observe the tilt-angle dependence of fish target strength in situ. – ICES Journal of Marine Science, 67: 215–230. A method of echotrace analysis (ETA), proposed by Furusawa and Miyanohana in 1988 utilizes successive echodata from an individual fish to obtain the target-strength (TS) pattern as a function of fish tilt angle and behaviour. The method can be applied to data from an echosounder with any beam configuration, single-, dual-, and split-beam. However, the method has not been applied rigorously to split-beam sounder data, which provide most comprehensive and accurate information. The aim of this work is to establish an accurate and practical ETA method for split-beam echosounder data. Although the basic theory had already been developed, some theoretical and practical enhancement was needed; smoothing of an echotrack by linear and quadratic regressions, correction for transducer motion, and comparison of an observed TS pattern with a prolate-spheroid theoretical model. The analysis starts from careful selection of a single echotrace on an echogram and ends with a composite display of results including a three-dimensional fish track and a TS pattern as a function of the tilt angle of the fish. The method was applied to typical echotrace examples, and utility and practicality were confirmed. A means of increasing the number of applicable echotraces is discussed.

The Sahara

2017 ◽  
Author(s):  
Barbara E. Barich
Keyword(s):  
Human Body ◽  
Manufacturing Process ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Dimensional Representation ◽  
Three Dimensional Representation ◽  
The Difference ◽  
Symbolic Content ◽  
The Relationship

This chapter discusses the collection of objects, in clay and stone, from various pastoral Saharan sites whose original core area lay between Libya (Tadrart Acacus) and Algeria (Tassili- n-Ajjer). The chapter starts from the general theme of the relationship between the figurines and the subjects they represent, and the difference between two-dimensional and three-dimensional representation. It goes on to discuss the manufacturing process of the clay specimens (dating from between 7000 and 4000 years ago) and the significance of the changes introduced by the Neolithic. Most of the items studied fall into the category of zoomorphic figurines, with only two anthropomorphic examples, and find in the depiction of cattle their most striking subject. These representations possess an evident symbolic content which must be framed within the pastoral ideology of the Saharan Neolithic. In the anthropomorphic figurines the representation of the human body also plays the role of recapturing the sense of wholeness.

The relationship between target strength frequency response and vertical swim velocity: a new approach for fish discrimination

2021 ◽  
Vol 34 ◽  
pp. 11
Author(s):  
Hikaru Homma ◽  
Ilia Ostrovsky
Keyword(s):  
Frequency Response ◽  
Target Strength ◽  
New Approach ◽  
Novel Approach ◽  
Acoustic Methods ◽  
Ecological Applications ◽  
The Difference ◽  
The Relationship ◽  
Diurnal Vertical Migrations

In-situ identification of fish species using acoustic methods is a key issue for fisheries research and ecological applications. We propose a novel approach to fish discrimination based on the relationship between target strength frequency response (TS(f)) and vertical swim velocity (VSV), as a proxy of fish body orientation. The measurements were carried out with a wideband echosounder on live fish of five species confined in a net cage. The data show a large dependence of TS(f) on VSV. To compare the variability of frequency responses of different fishes, we calculated ΔTS(f, VSV) as the difference between the TS(f) at given VSV and the TS(f) at VSV = 0, i.e. when the fish was swimming horizontally. We demonstrated that the relationships between ΔTS and VSV were similar for fish of the same species but dissimilar for different species. This implies that the acoustic fish discrimination in nature might be performed when the variations of the VSV can be measured from acoustically tracked fish. This can be a promising method for remote fish discrimination, for instance, for fish with diurnal vertical migrations. Further validation of this approach for fish recognition is required.

scholarly journals A method for evaluating the effects of biological factors on fish target strength

2003 ◽  
Vol 60 (3) ◽  
pp. 555-562 ◽  
Author(s):  
Elliott L Hazen ◽  
John K Horne
Keyword(s):  
Target Strength ◽  
Comparative Approach ◽  
Theragra Chalcogramma ◽  
Fish Length ◽  
Biological Factors ◽  
Backscatter Intensity ◽  
Relative Contribution ◽  
Walleye Pollock Theragra Chalcogramma ◽  
Improving Accuracy ◽  
The Relationship

Abstract Understanding the relationship between fish biology and target strength potentially improves the accuracy of acoustic assessments. The effects of individual biological factors (e.g., length, tilt, and depth) on backscatter amplitude have been examined, but the relative contribution of each factor has not been quantified. Dimensionless ratios, which facilitate comparison of disparate quantities, were used to evaluate the effects of individual biological factors on echo intensities. Ratios from 25 adult walleye pollock (Theragra chalcogramma) were calculated using a Kirchhoff-ray-mode, backscatter model parameterized for each fish. This comparative approach can be used to identify the influence of biological factors on backscatter intensity and is potentially a tool for improving accuracy when converting acoustic size to fish length.

scholarly journals Improvements to Reference Systems and Their Relationships

1995 ◽  
Vol 166 ◽  
pp. 309-314
Author(s):  
P. K. Seidelmann
Keyword(s):  
Reference Frame ◽  
Reference Frames ◽  
Three Dimensional ◽  
Reference Systems ◽  
Basic Frame ◽  
Dynamical Time ◽  
Optical Wavelengths ◽  
The Difference ◽  
The Relationship ◽  
Optical Radar

Reference Systems include the reference frames and their relationships, time arguments, ephemerides, and the standard constants and algorithms.The extragalactic, or radio, reference frame will be the basic frame. Achieving milli to microarcsecond accuracies at optical wavelengths will reduce the disparity between optical, radar, and radio reference frame determinations. Thus, the relationships and identifications of common sources should be much more accurate. Another significant change should be the ability to determine distances, and thus space motions on a three-dimensional basis, rather than the current two-dimensional basis of proper motions.Improvements in ephemerides provide the opportunity to investigate the difference between atomic and dynamical time, the relationship between the dynamical and extragalactic reference frame and the values of precession and nutation.Also, the relationships between the bright and faint optical catalogs, the infrared, and extragalactic reference frames should be better determined. Reference frames at other wavelengths will become determinable.

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