Gastric Digestion, Food Consumption, Feeding Periodicity, and Food Conversion Efficiency in Walleye (Stizostedion vitreum vitreum)

1973 ◽  
Vol 30 (9) ◽  
pp. 1327-1336 ◽  
Author(s):  
William A. Swenson ◽  
Lloyd L. Smith Jr.
Keyword(s):  
Conversion Efficiency ◽  
Consumption Rate ◽  
Early Morning ◽  
Stizostedion Vitreum ◽  
Gastric Digestion ◽  
Stizostedion Canadense ◽  
Force Feeding ◽  
Feeding Periodicity ◽  
Consumption Rates ◽  
Repeated Use

Gastric digestion of walleye, Stizostedion vitreum vitreum, and sauger, Stizostedion canadense, was measured by pumping stomachs at various intervals after experimental meals had been force-fed or voluntarily consumed. No significant differences in digestion rates were found between species or among walleye taken from three lakes. Repeated use of fish in digestion experiments failed to influence results. Gastric digestion rate increased with fish size, but was depressed by increased meal size, food particle size, and by force-feeding experimental meals.Food consumption rate and feeding chronology of the strong 1966 year-class of Lake of the Woods walleye were determined by applying results of laboratory digestion studies to stomach samples. An estimating technique that takes into account the effects of factors shown to influence digestion in the laboratory was developed and used to make calculations for the field population. Consumption averaged 1% of body weight during June, 2% during July, and 3% during August and September. Average temperatures were similar during June and September. Greater consumption during September resulted from higher food availability. Feeding was greatest during night and early morning hours in all months except June when it was continuous. Conversion efficiency of the 1966 year-class was described from estimates of growth and consumption rates for June through September and approximated 20% during each month.

Effects of prey resource fluctuation on predation attributes of two sympatric Coccinellidae (Coleoptera)

2015 ◽  
Vol 148 (4) ◽  
pp. 443-451 ◽  
Author(s):  
Desh Deepak Chaudhary ◽  
Bhupendra Kumar ◽  
Geetanjali Mishra ◽  
Omkar
Keyword(s):  
Growth Rate ◽  
Conversion Efficiency ◽  
Consumption Rate ◽  
Acyrthosiphon Pisum ◽  
Experimental Conditions ◽  
Propylea Dissecta ◽  
Consumption Rates ◽  
Prey Resources ◽  
Rearing Condition ◽  
Rate Conversion

AbstractUnder natural conditions, prey resources may fluctuate considerably in space and time; and predators are continuously faced with challenges of resource availability and use. In this study, effects of fluctuations (scarce/optimal/abundant) in biomass of pea aphid (Acyrthosiphon pisum (Harris); Hemiptera: Aphididae) during rearing and experimental conditions on certain predatory attributes (consumption rate/conversion, efficiency/growth rate) of two sympatric aphidophagous Coccinellidae (Coleoptera) were evaluated. Results revealed significant influence of rearing conditions on conversion efficiency and growth rate; and experimental conditions on all three predation attributes of Menochilus sexmaculatus (Fabricius) (Coleoptera: Coccinellidae). Larvae/adults of M. sexmaculatus had similar consumption rates per rearing condition, but exhibited highest and lowest consumption rates when abruptly shifted to abundant and scarce prey experimental conditions. Further, scarce prey reared larvae/adults of M. sexmaculatus displayed highest conversion efficiency and growth rate on optimal/abundant prey experimental condition(s). However, all three predation attributes of larvae/adults of Propylea dissecta (Mulsant) (Coleoptera: Coccinellidae) were influenced substantially by both the rearing and experimental conditions; and scarce prey reared larvae/adults exhibited highest predation attributes on optimal/abundant prey experimental condition(s). Moreover, predation attributes of M. sexmaculatus were higher than P. dissecta on the three experimental conditions. Therefore, this study suggests that M. sexmaculatus has a better compensatory ability to overcome prey resource fluctuation than P. dissecta.

Estimating oxygen consumption rates of arteriolar walls under physiological conditions in rat skeletal muscle

2005 ◽  
Vol 289 (1) ◽  
pp. H295-H300 ◽  
Author(s):  
Masahiro Shibata ◽  
Shigeru Ichioka ◽  
Akira Kamiya
Keyword(s):  
Vascular Tone ◽  
Consumption Rate ◽  
Vascular Wall ◽  
Surrounding Tissue ◽  
Phosphorescence Quenching ◽  
Physiological Conditions ◽  
First Order ◽  
Vascular Walls ◽  
Consumption Rates

To examine the effects of vascular tone reduction on O2 consumption of the vascular wall, we determined the O2 consumption rates of arteriolar walls under normal conditions and during vasodilation induced by topical application of papaverine. A phosphorescence quenching technique was used to quantify intra- and perivascular Po2 in rat cremaster arterioles with different branching orders. Then, the measured radial Po2 gradients and a theoretical model were used to estimate the O2 consumption rates of the arteriolar walls. The vascular O2 consumption rates of functional arterioles were >100 times greater than those observed in in vitro experiments. The vascular O2 consumption rate was highest in first-order (1A) arterioles, which are located upstream, and sequentially decreased downstream in 2A and 3A arterioles under normal conditions. During papaverine-induced vasodilation, on the other hand, the O2 consumption rates of the vascular walls decreased to similar levels, suggesting that the high O2 consumption rates of 1A arterioles under normal conditions depend in part on the workload of the vascular smooth muscle. These results strongly support the hypothesis that arteriolar walls consume a significant amount of O2 compared with the surrounding tissue. Furthermore, the reduction of vascular tone of arteriolar walls may facilitate an efficient supply of O2 to the surrounding tissue.

scholarly journals Comparative Study of a Powerplant Life Consumption Rate When Installed in Two Different Aircraft Variants

Aerospace ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 327
Author(s):  
Ioannis Templalexis ◽  
Ioannis Lionis ◽  
Nikolaos Christou
Keyword(s):  
Air Force ◽  
Consumption Rate ◽  
Low Cycle Fatigue ◽  
Rotor Blades ◽  
Parameter Method ◽  
Great Level ◽  
Consumption Rates ◽  
Life Consumption ◽  
Mission Profile ◽  
Engine Life

The Hellenic Air Force (HAF) operates both EMB-145 and EMB-135 LR versions of Embraer aircraft, used in surveillance and civil missions respectively. These aircraft are equipped with the same version of Rolls Royce, AE 3007 turbofan engine. This study aims to quantify and compare the life consumption rate of this engine when installed in each of the two aircraft variants. Two typical missions, one for each variant, were constructed based on mission profile data dictated by the aircraft commanders. For each mission profile segment, corresponding engine data were matched out of the engine recordings archives held by the Hellenic Air Force. The life consumption rate was based on the Low Cycle Fatigue (LCF) and creep cumulative detrimental effect on the rotor blades of the 1st High-Pressure Turbine stage. For the LCF, the rainflow method was used to determine the respective loading cycles, whereas the Larson - Miller parameter method was used to determine the consumed life fractions due to creep. The main conclusion of the study was that the engine when installed in the EMB-145 military variant, is much more loaded. Despite the fact absolute life consumption values could hide a great level of uncertainty, the comparative outcomes wherein errors are, to a certain extent, cancelled out, could be used as a rule of thumb when monitoring engine life consumption rates.

scholarly journals Design and Analysis of a Modified-atmosphere Package for Minimally Processed Romaine Lettuce

1996 ◽  
Vol 121 (4) ◽  
pp. 722-729 ◽  
Author(s):  
Kevin I. Segall ◽  
Martin G. Scanlon
Keyword(s):  
Shelf Life ◽  
Consumption Rate ◽  
Modified Atmosphere Packaging ◽  
Modified Atmosphere ◽  
Packaging Film ◽  
Romaine Lettuce ◽  
Minimally Processed ◽  
Headspace Gas ◽  
Consumption Rates ◽  
Critical Choice

The first goal of this study was to determine the packaging film O2 permeability required to maintain a steady-state O2 concentration of 3% in modified-atmosphere packaging (MAP) of minimally processed romaine lettuce (Lactuca sativa L.). The second goal of the study was to determine the extent to which MAP could preserve lettuce quality and consequently extend product shelf life. Oxygen consumption rates of commercially prepared lettuce samples were determined in a closed system for each of three atmospheres (3% O2 combined with either 6%, 10%, or 14% CO2). Enzymatic, quadratic, and linear mathematical models were compared to determine which best described the respiratory data. The linear model was the most suitable and was used to predict the O2 consumption rate of the minimally processed romaine lettuce under the desired package headspace gas concentrations. The predicted O2 consumption rate was used to calculate the necessary O2 permeability for the packaging film. Packages (21.6 × 25.4 cm) were constructed from a polypropylene-polyethylene-laminate film with the appropriate O2 permeability. Packaged samples were stored under three modified atmospheres (MAs) (3% O2 combined with either 6%, 10%, or 14% CO2) for 20 days, and headspace gas concentrations, lettuce appearance, and color were evaluated every other day. Growth of pectinolytic and lactic acid bacteria was also studied. The O2 consumption rate of the lettuce decreased with increasing CO2 levels. The O2 levels in the MA packages equilibrated at 7% to 11%. Compared to a control atmosphere of air, MAP delayed the development of tissue discoloration. Preliminary results indicated no effect of MAP on microbial growth. Of the three CO2 levels, 10% was slightly more effective than 6% and 14%. Critical choice of packaging permeabilities combined with MAP maintained the quality of minimally processed romaine lettuce and thereby increased shelf life by about 50%.

Performance evaluation of throat type updraft biomass gasifier using different biomass fuels

2021 ◽  
Vol 45 (03) ◽  
pp. 6-12
Author(s):  
D. K. Vyas ◽  
J. Sravankumar ◽  
J. J. Chavda
Keyword(s):  
Power Generation ◽  
Carbon Monoxide ◽  
Chemical Process ◽  
Consumption Rate ◽  
Calorific Value ◽  
Producer Gas ◽  
Saw Dust ◽  
Consumption Rates ◽  
Maize Cobs ◽  
Agro Residues

A biomass gasifier converts solid fuel such as wood waste, saw-dust briquettes and agro-residues into a gaseous fuel through a thermo-chemical process and the resultant gas can be used for thermal and power generation applications. The present research aims to evaluate the updraft biomass gasifier using different biomass for thermal application. The capacity of updraft gasifier was a 5-10 kg.h-1 and three types of biomass: maize cobs, sized wood and saw dust briquettes were used as fuel for producing producer gas by thermal application. The maximum carbon monoxide (CO), hydrogen (H2) and Methane (CH4) found were 14.8, 12.7 and 3.9%, 14.6, 13.7 and 3.9 % and 14.2, 13.5 and 3.9% at 5 kg.h-1 biomass consumption rate, respectively using maize cobs, sized wood and saw dust briquettes as fuel. The maximum and minimum producer gas calorific value was found 1120 and 1034 kcal.m-3; 1139 and 1034 kcal.m-3 and 1123 and 1036 kcal.m-3 at biomass consumption rate of 5 and 10 kg.h-1 using maize cobs, sized wood and saw dust briquettes as fuel respectively. The maximum gasifier efficiency of 77.94, 70.26 and 69.60% was found at the biomass consumption rate of 5 kg.h-1 using maize cobs, sized wood and saw dust briquettes as fuel, respectively. The minimum gasifier efficiency of 72.72, 64.49 and 64.90 % was found at the biomass consumption rate of 10 kg.h-1 using maize cobs, sized wood and saw dust briquettes as fuel in the system, respectively. The maximum overall thermal efficiency of 29.60, 30.65 and 23.69 % were found at the biomass consumption rates of 8, 7 and 7 kg.h-1 using maize cobs, sized wood and saw dust briquettes, respectively.

A comparison of the gill physiology of two euryhaline crab species, Callinectes sapidus and Callinectes similis: energy production, transport-related enzymes and osmoregulation as a function of acclimation salinity

1995 ◽  
Vol 198 (2) ◽  
pp. 349-358 ◽  
Author(s):  
S Piller ◽  
R Henry ◽  
J Doeller ◽  
D Kraus
Keyword(s):  
Oxygen Consumption ◽  
Energy Production ◽  
Consumption Rate ◽  
Callinectes Sapidus ◽  
Crab Species ◽  
Ion Concentrations ◽  
Low Salinity ◽  
Consumption Rates ◽  
Cytochrome Content ◽  
Mitochondrial Cytochromes

Callinectes sapidus and C. similis co-occur in estuarine waters above 15 salinity. Callinectes sapidus also inhabits more dilute waters, but C. similis is rarely found below 15 . Previous work suggests that C. sapidus may be a better hyperosmoregulator than C. similis. In this study, energy metabolism and the levels of transport-related enzymes in excised gills were used as indicators of adaptation to low salinity. Oxygen consumption rates and mitochondrial cytochrome content of excised gills increased in both species as acclimation salinity decreased, but to a significantly greater extent in C. similis gills. In addition, C. similis gills showed the same levels of carbonic anhydrase and Na+/K+-ATPase activities and the same degree of enzyme induction during low-salinity adaptation as has been reported for C. sapidus gills. However, hemolymph osmolality and ion concentrations were consistently lower in C. similis at low salinity than in C. sapidus. Therefore, although gills from low-salinity-acclimated C. similis have a higher oxygen consumption rate and more mitochondrial cytochromes than C. sapidus gills and the same level of transport-related enzymes, C. similis cannot homeostatically regulate their hemolymph to the same extent as C. sapidus.

A generic model to estimate food consumption: linking von Bertalanffy’s growth model with Beverton and Holt’s and Ivlev’s concepts of net conversion efficiency

2009 ◽  
Vol 66 (4) ◽  
pp. 683-700 ◽  
Author(s):  
Axel Temming ◽  
Jens P. Herrmann
Keyword(s):  
Food Consumption ◽  
Growth Model ◽  
Conversion Efficiency ◽  
Gadus Morhua ◽  
Generic Model ◽  
Similar Degree ◽  
Growth Equation ◽  
Von Bertalanffy ◽  
Gastric Evacuation ◽  
Consumption Rates

In this paper, a mathematical derivation is presented that links von Bertalanffy’s growth model with the concept of net conversion efficiency of Beverton and Holt, aiming at the development of an equation that can calculate food consumption rates of wild populations from parameters of the von Bertalanffy growth equation and an estimate of the net food conversion efficiency of Beverton and Holt. The derivation is based on Pauly’s version of the generalized von Bertalanffy equation, which allows the allometric exponent of the anabolism term to differ from 2/3, as in the standard von Bertalanffy equation. As a side product, a general model is formulated that describes the gross growth conversion efficiency (K1 of Ivlev) as a function of weight of the organism. The new equations for the estimation of food consumption are applied in two case studies, North Sea cod ( Gadus morhua ) and whiting ( Merlangius merlangus ), for which a variety of consumption estimates is available from conventional gastric evacuation-based methods. The new method produces results that show a similar degree of variability as was observed in various applications of the gastric evacuation method.

Do methanotrophs drive phosphorus mineralization in soil ecosystem?

2020 ◽  
Author(s):  
Santosh Ranjan Mohanty ◽  
Adarsh Kumar ◽  
Rakesh Parmar ◽  
Garima Dubey ◽  
Ashok Kumar Patra ◽  
...  
Keyword(s):  
Consumption Rate ◽  
Organic P ◽  
Soil Ecosystem ◽  
Inorganic P ◽  
Sodium Phytate ◽  
Feeding Cycle ◽  
Consumption Rates ◽  
Phosphorus Mineralization ◽  
Absolute Control ◽  
P Sources

Experiments were carried out to elucidate linkage between methane consumption and mineralization of P from different phosphorous sources. The treatments were no CH4 no P amendment absolute control, with CH4 no P amendment control, with CH4 + inorganic P as Ca3(PO4)2 and with CH4 + organic P (sodium phytate). P sources were added at 25 µg P g-1 soil. Soils were incubated to undergo three repeated CH4 feeding cycle referred as feeding cycle I, feeding cycle II, and feeding cycle III. CH4 consumption rate k (µg CH4 consumed g-1 soil d-1) was 0.297 ± 0.028 in no P amendment control, 0.457±0.016 in Ca3(PO4)2, and 0.627 ± 0.013 in sodium phytate. Rate k was stimulated by 2 to 6 times over CH4 feeding cycles and followed the trend of sodium phytate > Ca3(PO4)2 > no P amendment control. CH4 consumption stimulated P solubilization from Ca3(PO4)2 by a factor of 2.86. Acid phosphatase (µg paranitrophenol released g-1 soil h-1) was higher in sodium phytate than no P amendment control. Abundance of 16S rRNA and pmoA genes increased with CH4 consumption rates. The study suggested that CH4 consumption drive mineralization of unavailable inorganic and organic P sources in the soil ecosystem.

Larval and female footprints as feeding deterrent cues for immature stages of two congeneric ladybird predators (Coleoptera: Coccinellidae)

2014 ◽  
Vol 104 (5) ◽  
pp. 652-660 ◽  
Author(s):  
B. Kumar ◽  
G. Mishra ◽  
Omkar
Keyword(s):  
Growth Rate ◽  
Conversion Efficiency ◽  
Adult Female ◽  
Consumption Rate ◽  
Coccinella Septempunctata ◽  
Feeding Deterrent ◽  
Immature Stages ◽  
Developmental Duration ◽  
Species Specific ◽  
Rate Conversion

AbstractIn the present study predation parameters, i.e. consumption rate, conversion efficiency and growth rate, and total developmental duration of immature stages of two congeneric ladybirds, Coccinella septempunctata (L.) and Coccinella transversalis F., have been evaluated in presence of conspecific and heterospecific fourth instar larval and adult female tracks. We hypothesized that the semiochemicals within larval/adult female tracks might act as foraging/feeding deterrent pheromones (FDPs) and would reduce the predation parameters; and would prolong total developmental duration of ladybird predators. Results of the study positively affirmed our hypothesis. The deterrence in prey consumption and reduction in conversion efficiency and growth rate was density dependent with species-specific variations. Consumption rate, conversion efficiency, and growth rate of larval instars decreased and the total developmental duration of immature stages increased when exposed to an increasing density of zero, two, three, and four conspecific/heterospecific larval/adult female tracks. Between ladybird species, C. septempunctata had higher consumption rate, growth rate, and total developmental durations, whereas conversion efficiency was higher in C. transversalis. Despite the presence of semiochemical tracks as foraging barriers, early instars showed higher conversion efficiencies and growth rates, whereas fourth instars had highest consumption rate in all experimental treatments. The present study, therefore, suggests that semiochemical tracks significantly reduce the predation potential and prolong developmental duration of conspecifics and heterospecifics. They, thus behave as FDP.

CALCULATION OF THE LABOR CONSUMPTION RATE FOR SHUTTERING WORKS WHILST CONSIDERING UNCERTAINTIES

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Markus Kummer
Keyword(s):  
Risk Ratio ◽  
Consumption Rate ◽  
Material Consumption ◽  
Construction Costs ◽  
Valid Data ◽  
Consumption Rates ◽  
Time Parameters ◽  
Uncertain Input ◽  
Uncertain Input Data ◽  
Labor Consumption

Calculating construction costs and times is one of the most important and demanding tasks in construction management and economics. To arrive at a realistic calculation base, valid data and information is constantly being sought for labor consumption rates, output rates, productivity, material consumption, volumes in stock, number of transport cycles, and cost and time parameters that must be estimated or calculated ex ante. Ultimately, final cost and time parameters must be determined on the basis of such considerations and calculations. Accurate figures must be stated or submitted at the end of any analysis. These depend on the complexity of the building and on the conditions prevailing at the actual work stages and rely on more or less uncertain input data. One possible solution to this issue is to consider ranges that can deliver final conclusions on determined values. To systematically consider ranges in input parameters, this paper concentrates on applying probabilistic calculation methods based on Monte Carlo simulations. Key outcomes of probabilistic calculations include histograms that are used to directly capture the chance/risk ratio relative to a specific (selected) parameter. This paper presents a practical example of calculating the labor consumption rate for shuttering works to highlight the significance of the chosen chance/risk ratio and to show how it can be integrated into the systematic decision-making process adopted by the parties involved in the project.

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