Optimum Swimming Speeds in Fish: The Problem of Currents

1980 ◽  
Vol 37 (7) ◽  
pp. 1086-1092 ◽  
Author(s):  
Clifford L. Trump ◽  
William C. Leggett
Keyword(s):  
Energy Expenditure ◽  
Swimming Speed ◽  
Current Velocity ◽  
Migration Behavior ◽  
Fish Swimming ◽  
Retrograde Motion ◽  
The Mean ◽  
The Relationship ◽  
Mean Current ◽  
A Current

A model is presented describing the energetic consequences of various behavioral responses to currents. To minimize the energy cost of migration, when confronted with currents, fish must optimize both the mean swimming speed and the degree to which swimming speed is altered in response to changes in current velocity. The optimum swimming speed in a current is U0 + 1/b where U0 = mean current speed and b is a constant in the equation E(t) = a ebW(t) describing the relationship between specific energy expenditure per unit time E(t) and swimming speed W(t). In a variable current, such as might occur in estuaries and coastal areas, energy expenditure is minimized when these variations are ignored and a constant speed through the water is maintained. This is true even in conditions where occasional retrograde motion over the bottom may occur. The added energy costs of swimming at mean speeds ≠ U0 + 1/b or of varying swimming speeds in response to changes in current velocity are rigorously defined. Predictions of the model are in general agreement with empirical data on fish swimming behavior.Key words: swimming speeds, currents, fish, theoretical ecology, mathematical models, energetics, migration, behavior

Obesity and Body Size Preferences of Jordanian Women

2010 ◽  
Vol 38 (1) ◽  
pp. 91-98 ◽  
Author(s):  
Hala Madanat ◽  
Steven R. Hawks ◽  
Heidi N. Angeles
Keyword(s):  
Body Size ◽  
Pearson Correlation ◽  
Nutrition Transition ◽  
The Body ◽  
Body Sizes ◽  
Ideal Body ◽  
The Mean ◽  
The Relationship ◽  
Mean Current ◽  
Healthy Body

The nutrition transition is associated with increased obesity rates and increased desire to be thin. This study evaluates the relationship between actual body size and desired body size among a representative sample of 800 Jordanian women. Using Stunkard’s body silhouettes, women were asked to identify their current and ideal body sizes, healthy body size, and their perception of the body size preferred by men. Body mass index (BMI) calculations indicate that 53.8% of the women were overweight or obese. Their mean current body size was 5, which is consistent with the mean BMI of 26 in the sample. Although 66% of the women were dissatisfied with their body size, the desired weight loss was not extreme. Pearson correlation was positive (.858, p <.0001) between measured BMI and body silhouettes chosen as an indicator of current body size. Jordanian women seemed pulled between the traditional and Westernized body preferences. Possible cultural explanations are explored.

scholarly journals WAVE BASIN EXPERIMENTS ON BOTTOM FRICTION DUE TO CURRENT AND WAVES

1986 ◽  
Vol 1 (20) ◽  
pp. 61 ◽  
Author(s):  
Paul J. Visser
Keyword(s):  
Laser Doppler Anemometer ◽  
Bottom Friction ◽  
Frictional Stress ◽  
Wave Basin ◽  
New Type ◽  
Mean Water Level ◽  
The Mean ◽  
The Waves ◽  
Mean Current ◽  
A Current

Results are presented of experiments in a wave basin on the increase of the mean bottom frictional stress in a flow when a wave field is superimposed on a current. The bottom friction was derived from the mean water level measured at various places. Measurements of wave orbital and mean current velocities were done both with a micro-propeller and with a new type immersible Laser Doppler Anemometer. The data indicate an increase of the mean bottom shear stress due to the presence of the waves, but less than predicted by Bijker (1967). A suggestion is made to improve the accuracy of this theory. The bottom stresses as predicted by Fredsoe (1984) are somewhat larger than the, experimental results.

A Theory Concerning the Distance Travelled by Animals Entering the Drift of a Stream

1970 ◽  
Vol 27 (2) ◽  
pp. 359-370 ◽  
Author(s):  
Colin McLay
Keyword(s):  
Maximum Distance ◽  
Rate Of Return ◽  
Individual Species ◽  
Drift Density ◽  
The Mean ◽  
Stream Drift ◽  
The Relationship ◽  
A Current

Stream bottom animals were introduced into a stream by disturbing the gravel at increasing distances upstream from a drift sampler. The relationship between the number of animals arriving at the sampler and distance of origin of the animals was found to be Nx = N0 e−RX where N0 is the number of animals introduced, R is the rate of return to the gravel of the animals, and X is the distance upstream from the sampler. The maximum distance travelled was 45.7 m and the mean distance 10.7 m. The values of R for individual species ranged from 0.0517 to 1.962 and values of the mean distance travelled from 19.3 to 0.5 m. Specific differences could be accounted for by differences in structure or behaviour of the animals.From these observations, a model of stream drift is developed. Two previously published experiments are shown to conform to model relationship: (1) recovery of drift density downstream from a blockage in the experiment of Waters (Ecology 46: 327–334, 1965); and (2) distribution of times taken to regain a foothold on the substrate by mayfly nymphs released into a current (Madsen, Flora Fauna 72: 148–154, 1966; Hydrobiologia 31: 337–349, 1968).Since a stationary feeding fish such as a trout can be considered to be a "drift sampler" intercepting particles in the current, some suggestions are made about the development of a theory concerning the delivery of items of food to such a predator.

scholarly journals Effect of tail fin loss on swimming capability and tail beat frequency of juvenile black carp Mylopharyngodon piceus

2020 ◽  
Vol 29 ◽  
pp. 71-77
Author(s):  
L Cai ◽  
J Chen ◽  
D Johnson ◽  
Z Tu ◽  
Y Huang
Keyword(s):  
Swimming Speed ◽  
Beat Frequency ◽  
Fish Swimming ◽  
Black Carp ◽  
No Tail ◽  
In The Wild ◽  
Group A ◽  
Mylopharyngodon Piceus ◽  
The Relationship ◽  
Tail Beat

Fin clipping is a common practice in fisheries management, and hatchery fish are often marked this way. In the wild, the tail (caudal) fin may be damaged or lost to predation or disease. Because the tail fin is important to fish swimming behavior and ability, this study was designed to examine the effects of partial and complete loss of the tail fin on the swimming ability of juvenile black carp Mylopharyngodon piceus. Swimming speed and tail beat frequency were measured for 3 groups (intact tail fin, partial tail fin, no tail fin) using a stepped velocity test conducted in a fish respirometer. We found that critical swimming speed (Ucrit) and burst speed (Uburst) decreased slightly in the partial fin group and significantly in the no fin group. In the group with no tail fin, Uburst decreased more than Ucrit, clearly reducing the ability to avoid predators. Moreover, mean tail beat frequency (TBFmean), Ucrit and Uburst all decreased slightly in the partial fin group and significantly in the no fin group. A decrease in tail beat force and TBF both reduce swimming capability. These findings contribute to developing our understanding of the relationship between fish tail fins and swimming.

scholarly journals Investigations on the Currents Influencing Iceberg Motion

1980 ◽  
Vol 1 ◽  
pp. 89-93 ◽  
Author(s):  
M. Dhalluin
Keyword(s):  
Southern Ocean ◽  
Surface Currents ◽  
The Mean ◽  
Natural Drift ◽  
Mean Current ◽  
A Current

Several factors contribute to the natural drift of an iceberg, and among these, currents play an important part on the translation and rotation. Some information exists on surface currents in sub-Antarctic areas, but an iceberg behaves as a current integrator due to its draught and it is assumed to drift under the action of a “mean” current. In order to measure the mean current, five drogued buoys were launched in July–August 1979. These buoys were located by Argos satellite transponders. The drift of the buoys gives the mean current from 0 to 230 m depth in the Southern Ocean. Some corrections must be made on the measured drifting speed of the drogued buoys, due to the influence of the wind on the above-water portion of the buoys.

Multi-Center Calibration of the Second Reference Material for Thromboplastin, Rabbit, Plain, Coded CRM 149R

1991 ◽  
Vol 65 (03) ◽  
pp. 263-267 ◽  
Author(s):  
A M H P van den Besselaar ◽  
R M Bertina
Keyword(s):  
Reference Material ◽  
Standard Error ◽  
Standard Errors ◽  
Sensitivity Index ◽  
Long Term Stability ◽  
Significant Bias ◽  
The Mean ◽  
The Relationship ◽  
International Sensitivity Index

SummaryIn a collaborative trial of eleven laboratories which was performed mainly within the framework of the European Community Bureau of Reference (BCR), a second reference material for thromboplastin, rabbit, plain, was calibrated against its predecessor RBT/79. This second reference material (coded CRM 149R) has a mean International Sensitivity Index (ISI) of 1.343 with a standard error of the mean of 0.035. The standard error of the ISI was determined by combination of the standard errors of the ISI of RBT/79 and the slope of the calibration line in this trial.The BCR reference material for thromboplastin, human, plain (coded BCT/099) was also included in this trial for assessment of the long-term stability of the relationship with RBT/79. The results indicated that this relationship has not changed over a period of 8 years. The interlaboratory variation of the slope of the relationship between CRM 149R and RBT/79 was significantly lower than the variation of the slope of the relationship between BCT/099 and RBT/79. In addition to the manual technique, a semi-automatic coagulometer according to Schnitger & Gross was used to determine prothrombin times with CRM 149R. The mean ISI of CRM 149R was not affected by replacement of the manual technique by this particular coagulometer.Two lyophilized plasmas were included in this trial. The mean slope of relationship between RBT/79 and CRM 149R based on the two lyophilized plasmas was the same as the corresponding slope based on fresh plasmas. Tlowever, the mean slope of relationship between RBT/79 and BCT/099 based on the two lyophilized plasmas was 4.9% higher than the mean slope based on fresh plasmas. Thus, the use of these lyophilized plasmas induced a small but significant bias in the slope of relationship between these thromboplastins of different species.

Disease and Civilization: A Scottish Atlantic Network of Physicians in the Enlightenment

2017 ◽  
Vol 10 (2) ◽  
pp. 197-216
Author(s):  
Sarah Irving-Stonebraker
Keyword(s):  
Nineteenth Century ◽  
Native Americans ◽  
Early Nineteenth Century ◽  
The Enlightenment ◽  
Historical Progress ◽  
Practice Of Medicine ◽  
Benjamin Rush ◽  
American Physician ◽  
The Relationship ◽  
A Current

Through an examination of the extensive papers, manuscripts and correspondence of American physician Benjamin Rush and his friends, this article argues that it is possible to map a network of Scottish-trained physicians in the late eighteenth and early nineteenth-century Atlantic world. These physicians, whose members included Benjamin Rush, John Redman, John Morgan, Adam Kuhn, and others, not only brought the Edinburgh model for medical pedagogy across the Atlantic, but also disseminated Scottish stadial theories of development, which they applied to their study of the natural history and medical practices of Native Americans and slaves. In doing so, these physicians developed theories about the relationship between civilization, historical progress and the practice of medicine. Exploring this network deepens our understanding of the transnational intellectual geography of the eighteenth and early nineteenth century British World. This article develops, in relation to Scotland, a current strand of scholarship that maps the colonial and global contexts of Enlightenment thought.

Evaluation of the Efficacy of ST2 and NT-proBNP in the Diagnosis and Prediction of Short- Term Prognosis in Heart Failure with Reduced Ejection Fraction

2017 ◽  
Vol 9 (04) ◽  
Author(s):  
Shivananda B Nayak ◽  
Dharindra Sawh ◽  
Brandon Scott ◽  
Vestra Sears ◽  
Kareshma Seebalack ◽  
...  
Keyword(s):  
Heart Failure ◽  
Ejection Fraction ◽  
Cardiac Biomarkers ◽  
Double Blind Study ◽  
Short Term ◽  
Double Blind ◽  
Reduced Ejection Fraction ◽  
The Mean ◽  
Design And Methods ◽  
The Relationship

Purpose: i) To determine the relationship between the cardiac biomarkers ST2 and NT-proBNP with ejection fraction (EF) in heart failure (HF) patients. ii) Assess whether a superiority existed between the aforementioned cardiac markers in diagnosing the HF with reduced EF. iii) Determine the efficacy of both biomarkers in predicting a 30-day cardiovascular event and rehospitalization in patients with HF with reduced EF iv) To assess the influence of age, gender, BMI, anaemia and renal failure on the ST2 and NT-proBNP levels. Design and Methods: A prospective double-blind study was conducted to obtain data from a sample of 64 cardiology patients. A blood sample was collected to test for ST2 and NT-proBNP. An echocardiogram (to obtain EF value), electrocardiogram and questionnaire were also obtained. Results: Of the 64 patients enrolled, 59.4% of the population had an EF less than 40%. At the end of the 30- day period, 7 patients were warded, 37 were not warded, one died and 17 were non respondent. Both biomarkers were efficacious at diagnosing HF with a reduced EF. However, neither of them were efficacious in predicting 30-day rehospitalization. The mean NT-proBNP values being: not rehospitalized (2114.7486) and 30 day rehospitalization (1008.42860) and the mean ST2 values being: not rehospitalized (336.1975), and 30-day rehospitalization. (281.9657). Conclusion: Neither ST2 or NT-proBNP was efficacious in predicting the short- term prognosis in HF with reduced EF. Both however were successful at confirming the diagnosis of HF in HF patients with reduced EF.

scholarly journals Correlation between fundus autofluorescence and visual function in patients with cone-rod dystrophy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Satoru Kanda ◽  
Takumi Hara ◽  
Ryosuke Fujino ◽  
Keiko Azuma ◽  
Hirotsugu Soga ◽  
...  
Keyword(s):  
Visual Field ◽  
Significant Relationship ◽  
Fundus Autofluorescence ◽  
Univariate Analysis ◽  
Retrospective Chart Review ◽  
Mean Deviation ◽  
Wide Field ◽  
The Mean ◽  
The Relationship ◽  
Field Imaging

AbstractThis study aimed to investigate the relationship between autofluorescence (AF) signal measured with ultra-wide field imaging and visual functions in patients with cone-rod dystrophy (CORD). A retrospective chart review was performed for CORD patients. We performed the visual field test and fundus autofluorescence (FAF) measurement and visualized retinal structures with optical coherence tomography (OCT) on the same day. Using binarised FAF images, we identified a low FAF area ratio (LFAR: low FAF/30°). Relationships between age and logMAR visual acuity (VA), central retinal thickness (CRT), central choroidal thickness (CCT), mean deviation (MD) value, and LFAR were investigated. Thirty-seven eyes of 21 CORD patients (8 men and 13 women) were enrolled. The mean patient age was 49.8 years. LogMAR VA and MD were 0.52 ± 0.47 and − 17.91 ± 10.59 dB, respectively. There was a significant relationship between logMAR VA and MD (p = 0.001). LogMAR VA significantly correlated with CRT (p = 0.006) but not with other parameters. Conversely, univariate analysis suggested a significant relationship between MD and LFAR (p = 0.001). In the multivariate analysis, LFAR was significantly associated with MD (p = 0.002). In conclusion, it is useful to measure the low FAF area in patients with CORD. The AF measurement reflects the visual field deterioration but not VA in CORD.

Heart Rate and Neurological Outcomes in Patients Undergoing Targeted Temperature Management

2020 ◽  
pp. 088506662098250
Author(s):  
Chad M. Conner ◽  
William H. Perucki ◽  
Andre Gabriel ◽  
David M. O’Sullivan ◽  
Antonio B. Fernandez
Keyword(s):  
Heart Rate ◽  
Positive Association ◽  
Targeted Temperature Management ◽  
Temperature Management ◽  
Neurological Outcomes ◽  
Neurologic Outcomes ◽  
Resuscitation Guidelines ◽  
The Mean ◽  
The Impact ◽  
The Relationship

Introduction: There is a paucity of data evaluating the impact of heart rate (HR) during Targeted Temperature Management (TTM) and neurologic outcomes. Current resuscitation guidelines do not specify a HR goal during TTM. We sought to determine the relationship between HR and neurologic outcomes in a single-center registry dataset. Methods: We retrospectively studied 432 consecutive patients who completed TTM (33°C) after cardiac arrest from 2008 to 2017. We evaluated the relationship between neurologic outcomes and HR during TTM. Pittsburgh Cerebral Performance Categories (CPC) at discharge were used to determine neurological recovery. Statistical analysis included chi square, Student’s t-test and Mann-Whitney U. A logistic regression model was created to evaluate the strength of contribution of selected variables on the outcome of interest. Results: Approximately 94,000 HR data points from 432 patients were retrospectively analyzed; the mean HR was 82.17 bpm over the duration of TTM. Favorable neurological outcomes were seen in 160 (37%) patients. The mean HR in the patients with a favorable outcome was lower than the mean HR of those with an unfavorable outcome (79.98 bpm vs 85.67 bpm p < 0.001). Patients with an average HR of 60-91 bpm were 2.4 times more likely to have a favorable neurological outcome compared to than HR’s < 60 or > 91 (odds ratio [OR] = 2.36, 95% confidence interval [CI] 1.61-3.46, p < 0.001). Specifically, mean HR’s in the 73-82 bpm range had the greatest rate of favorable outcomes (OR 3.56, 95% CI 1.95-6.50), p < 0.001. Administration of epinephrine, a history of diabetes mellitus and hypertension all were associated with worse neurological outcomes independent of HR. Conclusion: During TTM, mean HRs between 60-91 showed a positive association with favorable outcomes. It is unclear whether a specific HR should be targeted during TTM or if heart rates between 60-91 bpm might be a sign of less neurological damage.

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