Comparison of the Feeding Behaviour of Calanus and Pseudocalanus in two Experimentally Manipulated Enclosed Ecosystems

1982 ◽  
Vol 62 (1) ◽  
pp. 71-91 ◽  
Author(s):  
Roger P. Harris
Keyword(s):  
Particle Size ◽  
Body Size ◽  
Metabolic Rate ◽  
Feeding Behaviour ◽  
Model Development ◽  
Size Composition ◽  
Small Cells ◽  
Small Copepod ◽  
Experimental Support ◽  
Large Copepod

INTRODUCTIONImplicit in some recent models of the dynamics of planktonic systems, for example that of Steele & Frost (1977) is the concept that filter-feeding copepods may be scaled by size when considering feeding in relation to the size composition of their paniculate food. For a particular organism ingestion of phytoplankton has been considered to be a function of its own weight and the size composition of the phytoplankton available to it. Such scaling has been assumed to occur both in an intra- and interspecific sense, with model development involving a ‘large’ copepod {Calanus) able to feed and grow more efficiently on ‘large’ cells (diatoms) and a ‘small’ copepod {Pseudocalanus) better adapted to feed on ‘small’ cells (flagellates). However, although the general relationship between growth and metabolic rate and body size is widely accepted (Banse, 1976; Fenchel, 1974) this relationship between dietary particle-size composition and size of organism has remained a working hypothesis with little experimental support..

Development of Prediction Models for Particle Size Composition on Urban Road Surfaces

2015 ◽  
Vol 743 ◽  
pp. 450-457
Author(s):  
An Liu ◽  
Liang Liu ◽  
Dun Zhu Li ◽  
Yun Tao Guan
Keyword(s):  
Particle Size ◽  
Prediction Models ◽  
Critical Role ◽  
Model Development ◽  
Size Composition ◽  
Influential Factors ◽  
Stormwater Quality ◽  
Urban Road ◽  
Particle Size Composition ◽  
Road Surfaces

It is commonly known that particles play a critical role in urban stormwater quality because other pollutants can be attached to the particles and transported into receiving waters. Previous research studies have shown a strong relationship between pollutant build-up loads and particle sizes. In this context, accurately estimating the particle amounts in different sizes is extremely important since it can assist in predicting stormwater quality and hence contribute to effective stormwater quality improvement measures. This paper presents a robust model to predict particle size composition on urban road surfaces using heavy-duty vehicle volumes, traffic coefficient and road texture depth by multiple linear regression (MLR) method. The pollutants build-up data was used for model development and was collected on typical urban roads in Shenzhen, China. The relative prediction error and coefficient of variation values were found within the acceptable limits and hence indicated that the developed prediction models are relatively reliable. This developed model can assist in predicting particle size composition on urban road surfaces and thereby contribute to effective stormwater quality assessment and treatment design. Additionally, this developed modelling approach can also provide a guide in terms of particle size composition prediction using more influential factors.

scholarly journals Estimating maximum bite performance in Tyrannosaurus rex using multi-body dynamics

2012 ◽  
Vol 8 (4) ◽  
pp. 660-664 ◽  
Author(s):  
K. T. Bates ◽  
P. L. Falkingham
Keyword(s):  
Body Size ◽  
Feeding Behaviour ◽  
Ontogenetic Change ◽  
Positive Allometry ◽  
Musculoskeletal Models ◽  
Terrestrial Animal ◽  
Body Dynamics ◽  
Mode Of Life ◽  
Scaling Analyses ◽  
Multi Body

Bite mechanics and feeding behaviour in Tyrannosaurus rex are controversial. Some contend that a modest bite mechanically limited T. rex to scavenging, while others argue that high bite forces facilitated a predatory mode of life. We use dynamic musculoskeletal models to simulate maximal biting in T. rex . Models predict that adult T. rex generated sustained bite forces of 35 000–57 000 N at a single posterior tooth, by far the highest bite forces estimated for any terrestrial animal. Scaling analyses suggest that adult T. rex had a strong bite for its body size, and that bite performance increased allometrically during ontogeny. Positive allometry in bite performance during growth may have facilitated an ontogenetic change in feeding behaviour in T. rex , associated with an expansion of prey range in adults to include the largest contemporaneous animals.

scholarly journals Changes in body temperature influence the scaling of and aerobic scope in mammals

2006 ◽  
Vol 3 (1) ◽  
pp. 100-103 ◽  
Author(s):  
James F Gillooly ◽  
Andrew P Allen
Keyword(s):  
Body Size ◽  
Metabolic Rate ◽  
Size Dependence ◽  
Maximal Activity ◽  
Scaling Exponent ◽  
Temperature Influence ◽  
Aerobic Scope ◽  
Metabolic Scope ◽  
Single Power ◽  
Maximum Metabolic Rate

Debate on the mechanism(s) responsible for the scaling of metabolic rate with body size in mammals has focused on why the maximum metabolic rate ( ) appears to scale more steeply with body size than the basal metabolic rate (BMR). Consequently, metabolic scope, defined as /BMR, systematically increases with body size. These observations have led some to suggest that and BMR are controlled by fundamentally different processes, and to discount the generality of models that predict a single power-law scaling exponent for the size dependence of the metabolic rate. We present a model that predicts a steeper size dependence for than BMR based on the observation that changes in muscle temperature from rest to maximal activity are greater in larger mammals. Empirical data support the model's prediction. This model thus provides a potential theoretical and mechanistic link between BMR and .

scholarly journals Associations between Childhood Body Size, Composition, Blood Pressure and Adult Cardiac Structure: The Fels Longitudinal Study

PLoS ONE ◽  
2014 ◽  
Vol 9 (9) ◽  
pp. e106333 ◽  
Author(s):  
Roy T. Sabo ◽  
Miao-Shan Yen ◽  
Stephen Daniels ◽  
Shumei S. Sun
Keyword(s):  
Blood Pressure ◽  
Body Size ◽  
Longitudinal Study ◽  
Size Composition ◽  
Cardiac Structure

Respiratory Exchange and Body Size in the Aldabra Giant Tortoise

1971 ◽  
Vol 55 (3) ◽  
pp. 651-665 ◽  
Author(s):  
G. M. HUGHES ◽  
R. GAYMER ◽  
MARGARET MOORE ◽  
A. J. WOAKES
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Metabolic Rate ◽  
Relative Proportion ◽  
The Body ◽  
O2 Consumption ◽  
Weight Range ◽  
Testudo Hermanni ◽  
The Mean ◽  
Good Agreement

1. The O2 consumption and CO2 release of nine giant tortoises Testudo gigantea (weight range 118 g-35·5 kg) were measured at a temperature of about 25·5°C. Four European tortoises Testudo hermanni (weight range 640 g-2·16 kg) were also used. The mean RQ values obtained were 1·01 for T. gigantea and 0·97 for T. hermanni. These values were not influenced by activity or size. 2. The data was analysed by plotting log/log regression lines relating body weight to O2 consumption. Both maximum and minimum metabolic rates recorded for each individual T. gigantea showed a negative correlation with body weight. For active rates the relation was O2 consumption = 140·8W0·97, whereas for inactive animals O2 consumption = 45·47W0·82. 3. The maximum rates were obtained from animals that were observed to be active in the respirometer and the minimum rates from animals that remained quiet throughout. The scope for activity increased with body size, being 82 ml/kg/h for animals of 100 g and 103 ml/kg/h for 100 kg animals. The corresponding ratio between maximum and minimum rates increases from about 2 to 6 for the same weight range. 4. Values for metabolic rate in T. hermanni seem to be rather lower than in T. gigantea. Analysis of the relative proportion of the shell and other organs indicates that the shell forms about 31% of the body weight in adult T. hermanni but only about 18% in T. gigantea of similar size. The shell is not appreciably heavier in adult T. gigantea (about 20%). 5. Data obtained for inactive animals is in good agreement with results of other workers using lizards and snakes. Previous evidence suggesting that chelonians show no reduction in metabolic rate with increasing size is not considered to conflict with data obtained in the present work.

Relation between Metabolic Rate and Body Size in the Ovine Fetus

1987 ◽  
Vol 117 (6) ◽  
pp. 1181-1186 ◽  
Author(s):  
Alan W. Bell ◽  
Frederick C. Battaglia ◽  
Giacomo Meschia
Keyword(s):  
Body Size ◽  
Metabolic Rate ◽  
Ovine Fetus

scholarly journals The effect of liquid pig manure on the wheat yield, content and balance of nutrients in light-gray forest soil with light particle-size composition

2019 ◽  
Vol 20 (5) ◽  
pp. 456-466
Author(s):  
V. I. Titova ◽  
L. D. Varlamova ◽  
R. N. Rybin ◽  
T. V. Andronova
Keyword(s):  
Particle Size ◽  
Spring Wheat ◽  
Wheat Yield ◽  
Size Composition ◽  
Light Particle ◽  
Pig Manure ◽  
Wheat Crop ◽  
Dry Matter Content ◽  
Particle Size Composition ◽  
Positive Balance

The research has been carried out under production conditions on light gray forest soils with light particle-size composition at an area of 550 hectares where liquid pig manure (LPM) of a large pig breeding complex is annually used as an organic fertilizer at doses of 60 and 90 t/ha. The average characteristics of LPM are as follows: dry matter content is 9.5%, pH 7.7 units, nitrogen 0.22%, phosphorus 0.11%, and potassium 0.12%. The cultivated grain crops were presented by winter and spring wheat varieties, Moskovskaya 39 and Esther, respectively. It has been established that at the dose of 60 t/ha LPM for two years of research at an average a mean wheat yield was 3.0-3.75 t/ha, and at the dose of 90 t/ha - up to 4.75 t/ha. The return on investments for fertilizers in the “winter wheat → spring wheat” crop rotation link at the dose of 60 t/ha of LPM was 5.41 kg of grain per 1 kg of active substance of manure, at the dose of 90 t/ha - 4.57 kg / kg. A positive balance of nutritional elements developed on all fields, but it was better balanced when the dose of LPM was 60 t/ha and the yield was 3.0 t/ha of grain annually, or when the LPM dose was 90 t/ha and the yield of wheat was 4.75 t/ha. In this case, the estimated potassi-um supply of soil occurs at a lower rate than that of nitrogen and phosphorus. The application of 120 t of LPM during two years in total on loamy sand and of 180 t/ha on light loamy soil provided an increase in the content of mobile phosphorus compounds by 5-22 mg/kg, and potassium - by 11-30 mg/kg with a variation coefficient of 28-57% and 21-49%, respectively.

scholarly journals Influence of grain growth on the thermal structure of protoplanetary discs

2020 ◽  
Vol 640 ◽  
pp. A63 ◽  
Author(s):  
Sofia Savvidou ◽  
Bertram Bitsch ◽  
Michiel Lambrechts
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Grain Growth ◽  
Thermal Structure ◽  
Size Composition ◽  
Size Distributions ◽  
Migration Rates ◽  
Grain Size Distributions ◽  
Hydrodynamical Simulations ◽  
Protoplanetary Discs

The thermal structure of a protoplanetary disc is regulated by the opacity that dust grains provide. However, previous works have often considered simplified prescriptions for the dust opacity in hydrodynamical disc simulations, for example, by considering only a single particle size. In the present work, we perform 2D hydrodynamical simulations of protoplanetary discs where the opacity is self-consistently calculated for the dust population, taking into account the particle size, composition, and abundance. We first compared simulations utilizing single grain sizes to two different multi-grain size distributions at different levels of turbulence strengths, parameterized through the α-viscosity, and different gas surface densities. Assuming a single dust size leads to inaccurate calculations of the thermal structure of discs, because the grain size dominating the opacity increases with orbital radius. Overall the two grain size distributions, one limited by fragmentation only and the other determined from a more complete fragmentation-coagulation equilibrium, give comparable results for the thermal structure. We find that both grain size distributions give less steep opacity gradients that result in less steep aspect ratio gradients, in comparison to discs with only micrometer-sized dust. Moreover, in the discs with a grain size distribution, the innermost (<5 AU) outward migration region is removed and planets embedded in such discs experience lower migration rates. We also investigated the dependency of the water iceline position on the alpha-viscosity (α), the initial gas surface density (Σg,0) at 1 AU and the dust-to-gas ratio (fDG) and find rice ∝ α0.61Σg,00.8fDG0.37 independently of the distribution used in the disc. The inclusion of the feedback loop between grain growth, opacities, and disc thermodynamics allows for more self-consistent simulations of accretion discs and planet formation.

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