Effects of stomach stones on the buoyancy and equilibrium of a floating crocodilian: a computational analysis

2003 ◽  
Vol 81 (8) ◽  
pp. 1346-1357 ◽  
Author(s):  
Donald M Henderson
Keyword(s):  
Body Mass ◽  
Computational Analysis ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
The Body ◽  
Alligator Mississippiensis ◽  
Total Body Mass ◽  
Total Body ◽  
Negatively Buoyant ◽  
Buoyancy Control

A three-dimensional mathematical/computational model of the crocodilian Alligator mississippiensis has been developed to investigate the influence of gastroliths on crocodilian buoyancy. The model is self-correcting, recovers from large perturbations, and can replicate the body orientations and degrees of immersion seen in living crocodilians that have attained equilibrium with respect to the competing forces of buoyancy and weight. For a range of lung deflations where the model was still positively buoyant, adding gastroliths of mass equal to 1% of the body mass has the effect of lowering the body, on average, by 2.6% of the maximum trunk depth while simultaneously increasing the inclination of the body with its sagittal plane. With the lungs fully inflated, the model would become negatively buoyant only when loaded with stones weighing more than 6% of the total body mass. Without gastroliths the body would sink when the lungs were deflated by 40%–50%. In all situations the model was resistant to capsizing. The relatively small amounts of gastroliths (<2% body mass) found in aquatic tetrapods are considered to be inconsequential for buoyancy and stability, and the lungs are the principle agent for hydrostatic buoyancy control.

scholarly journals Physiomorphic Transformation in Extreme Endurance Migrants: Revisiting the Case of Bar-Tailed Godwits Preparing for Trans-Pacific Flights

2021 ◽  
Vol 9 ◽  
Author(s):  
Theunis Piersma ◽  
Robert E. Gill ◽  
Daniel R. Ruthrauff
Keyword(s):  
Body Mass ◽  
Time Window ◽  
The Body ◽  
Fat Free Mass ◽  
Published Data ◽  
Total Body Mass ◽  
Digestive Organs ◽  
Short Time Window ◽  
Muscle Groups ◽  
Total Body

In a 1998 paper entitled “Guts don’t fly: small digestive organs in obese bar-tailed godwits,” Piersma and Gill (1998) showed that the digestive organs were tiny and the fat loads huge in individuals suspected of embarking on a non-stop flight from Alaska to New Zealand. It was suggested that prior to migratory departure, these godwits would shrink the digestive organs used during fuel deposition and boost the size and capacity of exercise organs to optimize flight performance. Here we document the verity of the proposed physiomorphic changes by comparing organ sizes and body composition of bar-tailed godwits Limosa lapponica baueri collected in modesty midway during their fueling period (mid-September; fueling, n = 7) with the previously published data for godwits that had just departed on their trans-Pacific flight (October 19; flying, n = 9). Mean total body masses for the two groups were nearly identical, but nearly half of the body mass of fueling godwits consisted of water, while fat constituted over half of total body mass of flying godwits. The two groups also differed in their fat-free mass components. The heart and flight muscles were heavier in fueling godwits, but these body components constituted a relatively greater fraction of the fat-free mass in flying godwits. In contrast, organs related to digestion and homeostasis were heavier in fueling godwits, and most of these organ groups were also relatively larger in fueling godwits compared to flying godwits. These results reflect the functional importance of organ and muscle groups related to energy acquisition in fueling godwits and the consequences of flight-related exertion in flying godwits. The extreme physiomorphic changes apparently occurred over a short time window (≤1 month). We conclude that the inferences made on the basis of the 1998 paper were correct. The cues and stimuli which moderate these changes remain to be studied.

scholarly journals Melanocortin antagonism ameliorates muscle wasting and inflammation in chronic kidney disease

2012 ◽  
Vol 303 (9) ◽  
pp. F1315-F1324 ◽  
Author(s):  
Wai W. Cheung ◽  
Robert H. Mak
Keyword(s):  
Chronic Kidney Disease ◽  
Body Composition ◽  
Kidney Disease ◽  
Body Mass ◽  
Muscle Wasting ◽  
The Body ◽  
Central Administration ◽  
Total Body Mass ◽  
Body Composition Change ◽  
Total Body

Aberrant melanocortin signaling has been implicated in the pathogenesis of wasting in chronic kidney disease (CKD). Previously, we demonstrated that agouti-related peptide (AgRP), a melenocortin-4 receptor antagonist, reduced CKD-associated cachexia in CKD mice. Our previous studies with AgRP utilized dual energy X-ray (DXA) densitometry to assess the body composition in mice (Cheung W, Kuo HJ, Markison S, Chen C, Foster AC, Marks DL, Mak RH. J Am Soc Nephrol 18: 2517–2524, 2007; Cheung W, Yu PX, Little BM, Cone RD, Marks DL, Mak RH. J Clin Invest 115: 1659–1665, 2005). DXA is unable to differentiate water content in mice, and fluid retention in CKD may lead to an overestimate of lean mass. In this study, we employed quantitative magnetic resonance technique to evaluate body composition change following central administration of AgRP in a CKD mouse model. AgRP treatment improved energy expenditure, total body mass, fat mass, and lean body mass in CKD mouse. We also investigated the effect of CKD-associated cachexia on the signaling pathways leading to wasting in skeletal muscle, as well as whether these changes can be ameliorated by central administration of AgRP. AgRP treatment caused an overall decrease in proinflammatory cytokines, which may be one important mechanism of its effects. Muscle wasting in CKD may be due to the activation of proteolytic pathways as well as inhibition of myogenesis and muscle regeneration processes. Our results suggest that these aberrant pathological pathways leading to muscle wasting in CKD mice were ameliorated by central administration of AgRP.

scholarly journals The Relationship between Initial Tacrolimus Metabolism Rate and Recipients Body Composition in Kidney Transplantation

2021 ◽  
Vol 10 (24) ◽  
pp. 5793
Author(s):  
Aureliusz Kolonko ◽  
Patrycja Pokora ◽  
Natalia Słabiak-Błaż ◽  
Beata Czerwieńska ◽  
Henryk Karkoszka ◽  
...  
Keyword(s):  
Body Composition ◽  
Body Mass ◽  
Multivariate Regression Analysis ◽  
The Body ◽  
Tacrolimus Concentration ◽  
Kidney Transplant Recipients ◽  
Visceral Fat Area ◽  
Total Body Mass ◽  
Total Body ◽  
The Relationship

There are several premises that the body composition of kidney transplant recipients may play a role in tacrolimus metabolism early after transplantation. The present study aimed at analyzing the relationship between the body composition parameters assessed by bioimpedance analysis (BIA) and initial tacrolimus metabolism. Immediately prior to transplantation, BIA using InBody 770 device was performed in 122 subjects. Tacrolimus concentration-to-dose (C/D) ratio was calculated based on the first blood trough level measurement. There was no difference in phase angle, visceral fat area, lean body mass index (LBMI) and the proportion of lean mass as a percentage of total body mass between the subgroups of slow and fast metabolizers. However, subjects with LBMI ≥ median value of 18.7 kg/m2, despite similar initial tacrolimus dose per kg of body weight, were characterized by a significantly lower tacrolimus C/D ratio (median 1.39 vs. 1.67, respectively; p < 0.05) in comparison with the subgroup of lower LBMI. Multivariate regression analysis confirmed that age (rpartial = 0.322; p < 0.001) and LBMI (rpartial = −0.254; p < 0.01) independently influenced the tacrolimus C/D ratio. A LBMI assessed by BIA may influence the tacrolimus metabolism in the early post-transplant period and can be a useful in the optimization of initial tacrolimus dosing.

On the Nature of Hereditary Size Limitation

1929 ◽  
Vol 6 (4) ◽  
pp. 311-324
Author(s):  
R. CUMMING ROBB
Keyword(s):  
Body Weight ◽  
Body Mass ◽  
Physical Significance ◽  
Body Parts ◽  
Total Body Mass ◽  
Organ Growth ◽  
Submaxillary Glands ◽  
Size Limitation ◽  
Similar Association ◽  
Total Body

1. Throughout post-natal life the relative weights of the pituitary body, thyroid, thymus and adrenals in the rabbit may be expressed by the equation y = axk + c. 2. A similar association is indicated in the rat for the weights of eyeballs, liver, pancreas, hypophysis, thyroid, adrenals, submaxillary glands, kidney and fresh skeleton (data from Donaldson, 1924). 3. In giant and pigmy rabbits, the ultimate proportions of body parts are not the same, but (for any given body weight) corresponding tissues in the two groups tend to exhibit an identical relation to total body mass. 4. The adrenals and testes of the Polish rabbits are relatively much larger than those of the Flemish. But in each case the growth of the adrenal approximates to a constant power function of body weight. Moreover, in these two groups and in their hybrids, the growth of the testes adheres to a simple association with adrenal weight identical for each. 5. These data suggest the generalisation that in a growing organism the magnitude of any part tends to be a specific function of the total body mass or of some portion so related to the whole. 6. These associations may be explained by surmising that each tissue is in equilibrium with the internal milieu with regard to the distribution of nutrient growth essentials; that in each case the equilibrium point would be determined by the nature of the cell and after differentiation would tend to remain constant; and that the relative enlargement of each tissue is limited by the excess of the equilibrium value over the katabolic expenditure. 7. According to the above hypothesis of organ growth, the equation y = axk + c may possess a physical significance. Eight types of growth relationships may thus exist, differing because of the apparent inactivity of one or more constants in this equation.

scholarly journals Spatial and temporal variation in body mass and the blubber, muscle and visceral fat content of North Atlantic common minke whales

2020 ◽  
Vol 21 (1) ◽  
pp. 59-70
Author(s):  
Thorvaldur Gunnlaugsson
Keyword(s):  
Body Mass ◽  
North Atlantic ◽  
Visceral Fat ◽  
Energy Content ◽  
Posterior Part ◽  
The Body ◽  
Spatial And Temporal Variation ◽  
Total Body Mass ◽  
The North ◽  
Minke Whales

The exponent for predicting total body mass from length has been studied in many species and here data on common minke whales from areas in the North Atlantic is added from both Icelandic and Norwegian research catches. The exponent was found to be not significantly different from 3. In addition seasonal changes in body mass and in the parts of blubber, muscle and visceral fat are reported. The exponent for how blubber mass increases with length is lower than 3. In all cases a significant increase over the season was detected, in particular for the mature animals, and also in girth measurements, particularly at the posterior part of the body. Pregnant females had significantly more blubber than other whales. These results agree with studies on blubber thickness measurements and tissue energy content of Icelandic baleen whales and observed changes in the ecosystem around Iceland during the research period.

Body size, sexual dimorphism, and seasonal mass fluctuations in a larger sika deer subspecies, the Hokkaido sika deer (Cervus nippon yesoensis Heude, 1884)

2001 ◽  
Vol 79 (1) ◽  
pp. 154-159 ◽  
Author(s):  
Masatsugu Suzuki ◽  
Manabu Onuma ◽  
Mayumi Yokoyama ◽  
Koich Kaji ◽  
Masami Yamanaka ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Body Mass ◽  
Body Length ◽  
Sika Deer ◽  
Cervus Nippon ◽  
Total Body Mass ◽  
Foot Length ◽  
Hind Foot ◽  
Total Body ◽  
Cervus Nippon Yesoensis

Measurements of shoulder height, body length, hind-foot length, and total body mass were collected from 309 Hokkaido sika deer (Cervus nippon yesoensis Heude, 1884) (115 males and 194 females) and analyzed statistically for sexual dimorphism and seasonal body mass fluctuations. The von Bertalanffy equation was fitted to the growth curves that resulted. Asymptotic shoulder height, body length, and hind-foot length were 106.2, 112.6, and 52.9 cm in males and 94.8, 103.9, and 49.4 cm in females, respectively. Total body mass showed distinct seasonal fluctuations, ranging between 102.8 and 151.0 kg in adult males and 68.0 and 99.8 kg in adult females. Male/female ratios in shoulder height, body length, hind-foot length, and total mass were 1.12, 1.08, 1.07, and 1.51, respectively. These results indicate that the Hokkaido sika deer is one of the largest subspecies, at least in skeleton size. A larger body and longer hind foot would seem to be evolutionary adaptations to Hokkaido's cold, snowy environment.

scholarly journals Complete and Voluntary Starvation of 50 Days

2016 ◽  
Vol 9 ◽  
pp. CCRep.S39776 ◽  
Author(s):  
Bradley Elliott ◽  
Michelle Mina ◽  
Chrystalla Ferrier
Keyword(s):  
Decision Making ◽  
Body Mass ◽  
Clinical Decision Making ◽  
Clinical Decision ◽  
Activity Levels ◽  
Total Body Mass ◽  
Total Body ◽  
Linear Loss ◽  
Obese Male ◽  
Evidence Based Decision Making

A 34-year-old obese male (96.8 kg; BMI, 30.2 kg m−1) volitionally undertook a 50-day fast with the stated goal of losing body mass. During this time, only tea, coffee, water, and a daily multivitamin were consumed. Severe and linear loss of body mass is recorded during these 50 days (final 75.4 kg; BMI, 23.5 kg mT 1 ). A surprising resilience to effects of fasting on activity levels and physical function is noted. Plasma samples are suggestive of early impairment of liver function, and perturbations to cardiovascular dynamics are also noted. One month following resumption of feeding behavior, body weight was maintained (75.0 kg; BMI, 23.4 kg m−1). Evidence-based decision-making with the fasting or hunger striking patient is limited by a lack of evidence. This case report suggests that total body mass, not mass lost, may be a key observation in clinical decision-making during fasting and starvation.

scholarly journals Standardized MET Value Underestimates the Energy Cost of Treadmill Running in Men

2017 ◽  
Vol 38 (12) ◽  
pp. 890-896
Author(s):  
Helouane Ázara ◽  
Paulo Farinatti ◽  
Adrian Midgley ◽  
Fabrício Vasconcellos ◽  
Patrícia Vigário ◽  
...  
Keyword(s):  
Body Mass ◽  
Energy Cost ◽  
Fat Free Mass ◽  
Treadmill Running ◽  
Metabolic Equivalent ◽  
Total Body Mass ◽  
Healthy Men ◽  
Energy Cost Of Running ◽  
The Mean ◽  
Total Body

AbstractThe main purpose of the present study was to compare the reference metabolic equivalent (MET) value and observed resting oxygen uptake (VO2) for defining cardiorespiratory fitness (VO2max) and characterizing the energy cost of treadmill running. A heterogeneous cohort of 114 healthy men volunteered to participate. In Part 1 of the study, 114 men [mean±SD, age: 24±5 years; height: 177.1±7.9 cm; body mass: 75.0±10.0 kg] visited the laboratory twice for assessment of resting and maximal VO2 values to compare the reference MET value vs. observed resting VO2 and to investigate the association between resting VO2 and VO2max. In Part 2, 14 of the 114 men visited the laboratory once more to perform a 30-min bout of running at 8.0 km∙h−1/8.3 METs. The mean observed resting VO2 of 3.26 mL·kg−1·min−1 was lower than the reference MET value of 3.5 mL·kg−1·min−1 (P<0.001). Resting and maximal VO2 values relative to total body mass and fat-free mass were positively correlated (R=0.71 and 0.60, respectively; P<0.001). The maximal MET and energy cost of treadmill running were consequently underestimated when calculated using the reference MET value only for those with low VO2max (P=0.005 to P<0.001). In conclusion, the reference MET value considerably overestimated observed resting VO2 in men with low VO2max, resulting in underestimations of the maximal MET, exercise intensity prescription, and the energy cost of running.

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