scholarly journals Validation of the Labeled-Water Method for Estimating Food Consumption in Nestling Herons

The Auk ◽  
2002 ◽  
Vol 119 (2) ◽  
pp. 551-556
Author(s):  
Johanna H. Salatas ◽  
Peter C. Frederick ◽  
Kenneth A. Nagy ◽  
Gary E. Williams
Keyword(s):  
Water Content ◽  
Food Consumption ◽  
Average Error ◽  
Ecological Studies ◽  
Influx Rate ◽  
Water Influx ◽  
Isotope Method ◽  
Errors Analysis ◽  
Metabolic Water ◽  
Good Agreement

Abstract Accurate measurements of food consumption by young birds are of great value in a variety of ecological studies, but traditional measurement methods are problematic and prone to high error. In animals that obtain their water primarily through food, it is possible to estimate food consumption from measurements of water influx rate, using radioactively labeled water (3H2O), and diet water content. We evaluated that method by comparing actual food consumption with simultaneous estimates of food consumption based on the labeled-water method in captive-reared nestling Tricolored Herons (Egretta tricolor). There was good agreement. The average error in the isotope method was −2% (SD = 8%), and that difference was not statistically significant. An errors analysis indicated that the accuracy of this method is sensitive to determinations of dietary water content and animal body water content, and to estimates of rates of metabolic water production and unidirectional water vapor input.

scholarly journals Cellular water analysis in T cells reveals a switch from metabolic water gain to water influx

2020 ◽  
Author(s):  
A Saragovi ◽  
T Zilberman ◽  
G Yasur ◽  
K Turjeman ◽  
I Abramovich ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Growth ◽  
Water Content ◽  
Water Mass ◽  
Slow Phase ◽  
Second Phase ◽  
Water Influx ◽  
Cellular Water ◽  
Water Gain ◽  
Metabolic Water

AbstractCell growth is driven by the acquisition and synthesis of dry biomass and water mass. This study examines the increase of water in T cells biomass during cell growth. We found that T cell growth is initiated by a phase of slow increase of cellular water, followed by a second phase of rapid increase in water content. To study the origin of the water gain, we developed a novel method, Cold Aqua Trap – Isotope Ratio Mass Spectrometry (CAT-IRMS), which allows analysis of intracellular water isotope composition. Applying CAT-IRMS, we discovered that glycolysis-coupled metabolic water accounts on average for 11 femtoliter (fL) out of the 20 fL of water gained per cell during the slow phase. At the end of the rapid phase, before initiation of cell division, a water influx occurs, increasing the water level by three-fold. Thus, activated T cells switch from acquiring metabolic water to incorporating water from the extracellular medium. Our work provides a method to analyze cell water content and an insight into the way cells regulate their water mass.

Field Metabolic Rate, Water Flux, Food Consumption and Time Budget of Koalas, Phascolarctos Cinereus (Marsupialia: Phascolarctidae) in Victoria.

1985 ◽  
Vol 33 (5) ◽  
pp. 655 ◽  
Author(s):  
KA Nagy ◽  
RW Martin
Keyword(s):  
Metabolic Rate ◽  
Food Consumption ◽  
Time Budget ◽  
Metabolic Rates ◽  
Feeding Rates ◽  
Influx Rate ◽  
Phascolarctos Cinereus ◽  
Water Influx ◽  
Dry Food ◽  
Field Metabolic Rates

Doubly labelled water measurements in free-ranging adult koalas (9.2 kg) indicated that field metabolic rates averaged 0.434 ml CO2 g-�h-� (equivalent to 2090 kJ per animal per day, or 2.59 X basal metabolic rate). Females (7.8 kg) had significantly higher mass-specific metabolic rates than males (10.8 kg). Percentage apparent assimilation of dietary substances was 56% for dry matter, 52% for energy, 32% for nitrogen, and 66% for water. Feeding rates were about 222 g dry food per animal per day (equivalent to 510 g fresh food per animal per day) in both sexes. However, males had a higher water influx rate (475 ml per animal per day) than females (358 ml per animal per day), suggesting either that males selected more succulent food than females, or that males drank rainwater but females did not. Koalas consumed about twice as much dietary nitrogen as they required for maintenance. They maintained constant body masses, and (presumably) had balanced energy, water and nitrogen budgets during our 20-day study, while eating Eucalyptus ovata foliage. Koalas spent about 4.7 h eating, 4 min travelling, 4.8 h resting while awake and 14.5 h sleeping in a 24-h period. Their activity periods were not obviously restricted to periods of daylight or darkness, but were scattered through the 24 hours. In comparison with free-living, three-toed sloths Bradypus variegatus (4.08 kg) in central America, koalas had significantly higher mass-corrected field metabolic rates (391 kJ kg-0.75 day-� for koalas v.209 for sloths), water influx rates (69.9 ml kg-0.80 day-� for koalas v. 49.8 for sloths), and feeding rates (42.7 g dry food kg-0.75 day-� for koalas v. 21.2 for sloths). Unlike sloths, koalas did not bask in the morning sunshine, and one telemetered koala had a relatively constant body temperature over 24 h (c. 36�C), compared with daily variations between 30 and 38�C in sloths. Population food consumption (g dry food consumed ha-� day-�) was greater for koalas (681 v. 378 for sloths), and koalas consumed most of the leaf production of their preferred food species, E. ovata, which resulted in extensive defoliation of these trees. Although there is similarity in the ecological roles of koalas and sloths, their physiology and behaviour differ substantially.

The Utilisation of metabolic Water in Insects

1944 ◽  
Vol 35 (2) ◽  
pp. 127-139 ◽  
Author(s):  
G. Fraenkel ◽  
M. Blewett
Keyword(s):  
Body Weight ◽  
Water Content ◽  
Larval Development ◽  
Dry Weight ◽  
Larval Period ◽  
Tribolium Confusum ◽  
Ephestia Kuehniella ◽  
Final Size ◽  
Metabolic Water ◽  
Food Consumed

(1) Three insects,Tribolium confusum, Ephestia kuehniellaandDermestes vulpinus, have been grown at several humidities and the following factors have been determined: length of larval period; water content of food and of the freshly formed pupae; wet and dry weight of pupae and wet and dry weight of food consumed during larval development. The “net utilisation” of the food has been calculated as the ratio of dry weight of food eaten per larva to dry weight of pupa.(2) At lower humidities more food is eaten to produce a given unit of body weight. The length of the larval period increases and the weight of the pupae decreases.(3) More food is eaten at low humidities, because part of the food is utilised as water. As a consequence of this, the larva grows more slowly and its final size is smaller. It is shown forDermestesat 30 per cent. andEphestiaat 1 per cent. R.H. that less than 32·9 and 7·6 per cent. of the water in the pupae can be derived from water ingested with the food.

scholarly journals Soil water content estimation using ground penetrating radar data via group intelligence optimization algorithms: An application in the Northern Shaanxi Coal Mining Area

2020 ◽  
pp. 014459872097336
Author(s):  
Fan Cui ◽  
Jianyu Ni ◽  
Yunfei Du ◽  
Yuxuan Zhao ◽  
Yingqing Zhou
Keyword(s):  
Dielectric Constant ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Error Rate ◽  
Ground Penetrating Radar ◽  
Volumetric Water Content ◽  
Average Error ◽  
Average Error Rate ◽  
Ground Penetrating

The determination of quantitative relationship between soil dielectric constant and water content is an important basis for measuring soil water content based on ground penetrating radar (GPR) technology. The calculation of soil volumetric water content using GPR technology is usually based on the classic Topp formula. However, there are large errors between measured values and calculated values when using the formula, and it cannot be flexibly applied to different media. To solve these problems, first, a combination of GPR and shallow drilling is used to calibrate the wave velocity to obtain an accurate dielectric constant. Then, combined with experimental moisture content, the intelligent group algorithm is applied to accurately build mathematical models of the relative dielectric constant and volumetric water content, and the Topp formula is revised for sand and clay media. Compared with the classic Topp formula, the average error rate of sand is decreased by nearly 15.8%, the average error rate of clay is decreased by 31.75%. The calculation accuracy of the formula has been greatly improved. It proves that the revised model is accurate, and at the same time, it proves the rationality of the method of using GPR wave velocity calibration method to accurately calculate the volumetric water content.

A Mathematical Model Water Movement about Bottom-Water-Drive Reservoirs

1962 ◽  
Vol 2 (01) ◽  
pp. 44-52 ◽  
Author(s):  
Keith H. Coats
Keyword(s):  
Pore Volume ◽  
Bottom Water ◽  
Flow Model ◽  
Radial Flow ◽  
Water Movement ◽  
Gas Storage ◽  
Reservoir Pressure ◽  
Influx Rate ◽  
Aquifer System ◽  
Water Influx

Abstract This paper presents the development and solution of a mathematical model for aquifer water movement about bottom-water-drive reservoirs. Pressure gradients in the vertical direction due to water flow are taken into account. A vertical permeability equal to a fraction of the horizontal permeability is also included in the model. The solution is given in the form of a dimensionless pressure-drop quantity tabulated as a function of dimensionless time. This quantity can be used in given equations to compute reservoir pressure from a known water-influx rate, to predict water- in flux rate (or cumulative amount) from a reservoir- pressure schedule or to predict gas reservoir pressure and pore-volume performance from a given gas-in-place schedule. The model is applied in example problems to gas-storage reservoirs, and the difference between reservoir performances predicted by the thick sand model of this paper and the horizontal, radial-flow model is shown to be appreciable. Introduction The calculation of aquifer water movement into or out of oil and gas reservoirs situated on aquifers is important in pressure maintenance studies, material-balance and well-flooding calculations. In gas storage operations, a knowledge of the water movement is especially important in predicting pressure and pore-volume behavior. Throughout this paper the term "pore volume" denotes volume occupied by the reservoir fluid, while the term "flow model" refers to the idealized or mathematical representation of water flow in the reservoir-aquifer system. The prediction of water movement requires selection of a flow model for the reservoir-aquifer system. A physically reasonable flow model treated in detail to date is the radial-flow model considered by van Everdingen and Hurst. In many cases the reservoir is situated on top of the aquifer with a continuous horizontal interface between reservoir fluid and aquifer water and with a significant depth of aquifer underlying the reservoir. In these cases, bottom-water drive will occur, and a three-dimensional model accounting for the pressure gradient and water flow in the vertical direction should be employed. This paper treats such a model in detail--from the description of the model through formulation of the governing partial differential equation to solution of the equation and preparation of tables giving dimensionless pressure drop as a function of dimensionless time. The model rigorously accounts for the practical case of a vertical permeability equal to some fraction of the horizontal permeability. The pressure-drop values can be used in given equations to predict reservoir pressure from a known water-influx rate or to predict water-influx rate (or cumulative amount) when the reservoir pressure is known. The inclusion of gravity in this analysis is actually trivial since gravity has virtually no effect on the flow of a homogeneous, slightly compressible fluid in a fixed-boundary system subject to the boundary conditions imposed in this study. Thus, if the acceleration of gravity is set equal to zero in the following equations, the final result is unchanged. The pressure distribution is altered by inclusion of gravity in the analysis, but only by the time-constant hydrostatic head. The equations developed are applied in an example case study to predict the pressure and pore-volume behavior of a gas storage reservoir. The prediction of reservoir performance based on the bottom-water-drive model is shown to differ significantly from that based on van Everdingen and Hurst's horizontal-flow model. DESCRIPTION OF FLOW MODEL The edge-water-drive flow model treated by van Everdingen and Hurst is shown in Fig. 1a. The aquifer thickness is small in relation to reservoir radius water invades or recedes from the field at the latter's edges, and only horizontal radial flow is considered as shown in Fig. 1b. The bottom-water-drive reservoir-aquifer system treated herein is sketched in Fig. 2a and 2b. SPEJ P. 44^

scholarly journals How Precise are Size-Based Age Estimations in the Sand Lizard (Lacerta Agilis)?

2011 ◽  
Vol 56 (1-4) ◽  
pp. 11-17 ◽  
Author(s):  
Bartosz Borczyk ◽  
Łukasz Paśko
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Life Span ◽  
Age Estimation ◽  
The Body ◽  
Average Error ◽  
Ecological Studies ◽  
Age Classes ◽  
Sand Lizard ◽  
Lacerta Agilis

How Precise are Size-Based Age Estimations in the Sand Lizard (Lacerta Agilis)?Reptiles show a positive correlation between age and body size and it is common practice to infer the age of an animal from its size. However, the growth rate often differs between individuals, thus such practice may lead to false conclusions. Because age of an animal is a very important factor in many ecological studies, it should be determined with a minimum of error. Here, we compare the body size distribution among different age classes of the sand lizard (Lacerta agilis) to infer if it is possible to correctly determine their age on the basis of the body length. Our results show that the average error in age estimation on the basis of the lizard size is 1.36 year which is approximately 1/3 the average sand lizard life span.

scholarly journals Water content of aged aerosol

2011 ◽  
Vol 11 (3) ◽  
pp. 911-920 ◽  
Author(s):  
G. J. Engelhart ◽  
L. Hildebrandt ◽  
E. Kostenidou ◽  
N. Mihalopoulos ◽  
N. M. Donahue ◽  
...  
Keyword(s):  
Water Content ◽  
Water Uptake ◽  
Fine Particulate Matter ◽  
Sampling Site ◽  
Water Concentration ◽  
Organic Aerosol ◽  
Northern Coast ◽  
Volumetric Growth ◽  
Predicted Values ◽  
Good Agreement

Abstract. The composition and physical properties of aged atmospheric aerosol were characterized at a remote sampling site on the northern coast of Crete, Greece during the Finokalia Aerosol Measurement Experiment in May 2008 (FAME-2008). A reduced Dry-Ambient Aerosol Size Spectrometer (DAASS) was deployed to measure the aerosol water content and volumetric growth factor of fine particulate matter. The particles remained wet even at relative humidity (RH) as low as 20%. The aerosol was acidic during most of the measurement campaign, which likely contributed to the water uptake at low RH. The water content observations were compared to the thermodynamic model E-AIM, neglecting any contribution of the organics to aerosol water content. There was good agreement between the water measurements and the model predictions. Adding the small amount of water associated with the organic aerosol based on monoterpene water absorption did not change the quality of the agreement. These results strongly suggest that the water uptake by aged organic aerosol is relatively small (a few percent of the total water for the conditions during FAME-08) and generally consistent with what has been observed in laboratory experiments. The water concentration measured by a Q-AMS was well correlated with the DAASS measurements and in good agreement with the predicted values for the RH of the Q-AMS inlet. This suggests that, at least for the conditions of the study, the Q-AMS can provide valuable information about the aerosol water concentrations if the sample is not dried.

Model Study of Partial Structural Decomposition of Thaumasite

2015 ◽  
Vol 749 ◽  
pp. 8-12
Author(s):  
Eva Scholtzová ◽  
Daniel Tunega
Keyword(s):  
Experimental Data ◽  
Water Content ◽  
Dft Method ◽  
Decomposition Reaction ◽  
Structural Decomposition ◽  
Partial Decomposition ◽  
Model Study ◽  
Good Agreement

The DFT method was used for modeling a partial decomposition of the structure of the thaumasite mineral. The four models with a consecutive decreasing of water content were prepared (T12 – 100 %, T9 – 75 %, T6 – 50 %, T3 – 25 %) and corresponding decomposition enthalpies were calculated. The results showed a good agreement with available experimental data for the decomposition reaction of the thaumasite structure.

scholarly journals WATER INFLUX AND FOOD CONSUMPTION OF FREE-LIVING ORYXES (ORYX LEUCORYX) IN THE ARABIAN DESERT IN SUMMER

2002 ◽  
Vol 83 (3) ◽  
pp. 665-673 ◽  
Author(s):  
Stéphane Ostrowski ◽  
Joseph B. Williams ◽  
Eric Bedin ◽  
Khairi Ismail
Keyword(s):  
Food Consumption ◽  
Free Living ◽  
Water Influx

Zur Abscheidung von Methyljodid and Silberzeolithen / Investigations on the Fixation of Methyl Iodide by Silver Zeolites

1972 ◽  
Vol 27 (8-9) ◽  
pp. 1323-1328 ◽  
Author(s):  
C. Donner ◽  
T. Tamberg
Keyword(s):  
Gas Chromatography ◽  
Infrared Spectroscopy ◽  
Water Content ◽  
Methyl Iodide ◽  
Silver Ions ◽  
Reaction Products ◽  
Total Fixation ◽  
Heat Treated ◽  
Alkyl Iodides ◽  
Good Agreement

Abstract Alkyl iodides especially methyl iodide from the offgas of reactors and of reprocessing plants are difficult to remove.In earlier investigations it was shown that silver zeolites are qualified for a total fixation of methyl iodide, only when these sieves were exhaustively loaded with silver ions.In order to explain why only exhaustively loaded silver zeolites of type X are able to remove methyl iodide completely from the air, the reaction products from the chemisorption reaction were identified. The proportion of the silver ions that had reacted was calculated.Exhaustively loaded Ag-LMS-X pellets heat-treated at 400 °C (water content 0.94% by wt.) react with CH3I to form dimethylether.If the same pellets were gently dried with P2O5 (water content 15% by wt.) dimethylether and methanol were the products.The identification was done by gas chromatography and infrared spectroscopy.The chemisorption reaction can be described in the following way:a) CH3I + HOH+Ag+ →AgI + CH3OH + H+b) CH3I + CH3OH+Ag+ → AgI + CH3OCH3 + H+If only small concentrations of methyl-iodide and an excess of water vapour are present only methanol is expected.The experimental results are in good agreement with the assumptions.

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