scholarly journals The Oxygen Requirements of Certain Aquatic Animals and its Bearing Upon the Source of Food Supply

1925 ◽  
Vol 2 (3) ◽  
pp. 293-322
Author(s):  
W. J. DAKIN ◽  
CATHERINE M. G. DAKIN
Keyword(s):  
Organic Matter ◽  
Oxygen Consumption ◽  
Surface Area ◽  
Food Supply ◽  
Tap Water ◽  
The Body ◽  
Control Fish ◽  
Active Surface Area ◽  
Aquatic Animals ◽  
Waste Products

1. The original theory of the food supply of aquatic animals put forward by Pütter, and based upon the results of certain experiments and analyses, claimed that the chief source of food of such animals was organic matter dissolved in the sea, in lakes, rivers, etc., and that this was absorbed directly and indeed often by the gills, if present. The position he took up may be emphasised by his statement regarding fishes: "There is no doubt that a nutrition without dissolved foodstuffs is possible, and it is not impossible that cases of this kind are realised in nature. But the experiments at Naples show that the fish in the Naples aquarium under approximately natural conditions obtain one-half to threequarters or more of their food requirements by the absorption of dissolved food." 2. It is quite possible that small quantities of organic matter in solution in water are absorbed by aquatic animals, and in some cases (particularly amongst protozoa living under special conditions) this may be an important, perhaps the most important, source of food. It is also possible that very small quantities of organic matter in solution may eventually be found to exercise a very profound influence (acting like vitamines, for example) on the life of aquatic animals. Evidence for such is not evidence for the main thesis set up by Pütter on the results of his own experiments. 3. The food requirements of many aquatic animals as calculated by Pütter on the basis of oxygen consumption are often remarkably high and need further investigation. It is quite possible that there is an unknown factor at work here. In connection with these calculations we consider that purely theoretical computations based upon the measurement or estimation of the active surface area of the body are not permissible, and that the application of the law of surface area in connection.with metabolism must not be allowed to supplant experiment. 4. Experiments on goldfish similar to those made by Pütter, show that specimens kept in tap water without any particulate food live for varying periods (which are often of considerable duration) dependent upon the original condition of the fish, and the freedom of the experimental tanks from parasites. The addition of the organic compounds, glycerine and asparagine, makes no difference to the duration of life, and the consumption of oxygen by the fish living in tap water with these compounds does not exceed that of the control fish in tap water only. Gradual starvation takes place, and sections show that the mass of muscle tissue becomes gradually reduced. 5. The cessation of feeding on particulate food makes the fish particularly susceptible to the attacks of parasites (Chilodon cyprini and Gyrodactylus, sp.), if there is any chance of such infection. 6. The consumption of oxygen by plaice eggs during their development agrees fairly well with the amount computed from analyses of the composition of young eggs and eggs shortly before hatching, but the results are only approximate, although they fit in with the assumption that such floating eggs have their own food stores and absorb nothing from the sea water. 7. Aquatic organisms are not to be grouped in one class in so far as nutrition and metabolism are concerned. 8. It had frequently been noted that when the oxygen consumption of aquatic animals is measured, and the determination extends over several hours there is a gradual falling off during the experiment. It is necessary to look for this in every case before estimating the normal oxygen consumption over long periods. The variation may be due to handling the specimens at the beginning of the experiment, to the gradual reduction of the oxygen available, to the accumulation of waste products, or to time of feeding. We have found that goldfish, axolotls, and Anodon used in our experiments are to a certain extent independent of the oxygen pressure, which may fall considerably (until a certain minimum is reached) before the oxygen consumption of the animals per hour is affected.

Calculation of Surface Area of the Body

PEDIATRICS ◽  
1960 ◽  
Vol 25 (4) ◽  
pp. 727-730
Author(s):  
L. JEROME KROVETZ
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Surface Area ◽  
The Body ◽  
Personal Preference ◽  
Corrective Factor ◽  
The Relationship ◽  
Homeostatic Mechanisms

Several recent commentaries have been concerned primarily with the use of surface area of the body as a means of computing parenteral fluid dosages. Since there is, fortunately, a reasonably wide latitude of bodily homeostatic mechanisms, it becomes largely a matter of personal preference whether one utilizes surface area to estimate initial dosages or some other scheme to apply a corrective factor to weight-age relationships. There exists another more profound facet to this issue, namely the relationship, if any, of surface area of the body to such physiologic variables as cardiac output, oxygen consumption, renal functioin, etc. It seems logical to separate three areas for discussion.

An Examination of Efficiency during Walking in Children and Adults

1992 ◽  
Vol 4 (1) ◽  
pp. 36-49 ◽  
Author(s):  
Christine J. Ebbeling ◽  
Joseph Hamill ◽  
Patty S. Freedson ◽  
Thomas W. Rowland
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Surface Area ◽  
Body Surface ◽  
Walking Speed ◽  
The Body ◽  
Biomechanical Analysis ◽  
Scaling Effects ◽  
The Subject ◽  
Work Done

This study compared metabolic, kinematic, and efficiency parameters in 10 boys and 10 men while walking at speeds of similar relative intensities. Heart rate and oxygen consumption were monitored throughout the exercise and a sagittal view of the subject was filmed for biomechanical analysis. Angles of the hip, knee, and ankle changed with an increase in walking speed. There were kinematic differences between children and adults at the hip and knee. Heart rate and oxygen consumption (ml•kg−1•min−1) were greater in the children. There were no significant differences between children and adults when VO2 was normalized by body surface area rather than body mass. The work done by the body was greater in the adults, whereas the energy used was greater in the children. Therefore the children appeared less efficient. The reasons for the efficiency difference are not well documented. Scaling effects may be involved and therefore should be taken into consideration when comparing children and adults.

Biometry of the branchial plume in the hydrothermal vent tubeworm Riftia pachyptila (Vestimentifera; Annelida)

2002 ◽  
Vol 80 (2) ◽  
pp. 320-332 ◽  
Author(s):  
Ann C Andersen ◽  
Sylvie Jolivet ◽  
Stéphanie Claudinot ◽  
François H Lallier
Keyword(s):  
Surface Area ◽  
Body Mass ◽  
Hydrothermal Vent ◽  
The Body ◽  
Riftia Pachyptila ◽  
Aquatic Animals ◽  
Trunk Length ◽  
Planimetric Measurements ◽  
Negative Growth

The branchial plume of the hydrothermal vent tubeworm Riftia pachyptila is the main organ by which this mouth- and gut-less tubeworm directly exchanges metabolites with its environment. We estimated the total branchial surface area per unit wet mass, termed the specific branchial surface area (SBSA), from planimetric measurements. Changes in the SBSA during the growth of the worm were inferred from 16 individuals ranging from 1 to 112 g wet mass. Riftia pachyptila has a mean SBSA of 22 cm2·g–1, the second highest among all aquatic animals, representing 9 times the surface area of the rest of the body. Three significantly different classes of SBSA could be distinguished, corresponding to small, medium-sized, and large individuals. The SBSA values for small and medium-sized R. pachyptila are twice that for large individuals. Negative growth allometry between the length of the branchial plume and that of the trunk may be correlated with this variation in SBSA, the plume growing faster than the trunk in the small and medium-sized groups. In large individuals the trunk length exceeds the plume length, inducing an increase in body mass that lowers the SBSA. However, a lower SBSA does not imply reduced metabolite diffusion through the plume of large tubeworms, since their longer free filaments bear more developed pinnules, which are probably the preferred pathway of metabolite diffusion, owing to a minimal transepithelial distance of 2 µm.

scholarly journals The effectiveness of using a microbiological strain in the aquaponics system

2021 ◽  
Vol 937 (3) ◽  
pp. 032037
Author(s):  
O Krotova ◽  
O Polozyuk ◽  
K Savenkov ◽  
D Mashtykov ◽  
M Savenkova
Keyword(s):  
Carbon Dioxide ◽  
Organic Matter ◽  
Phosphorus Compounds ◽  
Toxic Substances ◽  
Aquatic Animals ◽  
Waste Products ◽  
Second Stage ◽  
The Third ◽  
Third Stage ◽  
Living Organisms

Abstract Aquaponics is an artificial ecosystem in which three types of living organisms are key: aquatic animals (usually fish or shrimp), plants and bacteria. This technology works on the principle of an ecosystem of fish and plants: fish provides food to plants, and plants purify water and are environmentally friendly. The essence of this method is to use the vital waste of aquatic animals (fish, shrimp) as a nutrient medium for plants. The essence of the method of operation of the aquaponic system is to use the vital waste of aquatic animals as food for plants. At the first stage, the fish produces waste products. Then, in the second stage, microbes and worms convert the waste into fertilizers for plants. During the process, at the third stage, plants consume the necessary products of excretion of living organisms. These are chemicals such as nitrogenous, potassium, phosphorus compounds, carbon dioxide. Thanks to aquaponic farms, the costs of water and other natural resources, soil pollution and the use of insecticides are already being reduced in different places of our planet. Such systems are a sustainable ecosystem capable of producing organic matter that does not contain toxic substances often present in vegetables grown by traditional methods.

The use of Body Surface Index as a Better Clinical Health indicators Compare to Body Mass Index and Body Surface Area for Clinical Application

2018 ◽  
pp. 131-136
Author(s):  
Shirazu I. ◽  
Theophilus. A. Sackey ◽  
Elvis K. Tiburu ◽  
Mensah Y. B. ◽  
Forson A.
Keyword(s):  
Surface Area ◽  
Body Surface Area ◽  
Clinical Application ◽  
Body Surface ◽  
Body Height ◽  
Health Indicators ◽  
The Body ◽  
Body Parameters ◽  
The Relationship ◽  
Individual Body

The relationship between body height and body weight has been described by using various terms. Notable among them is the body mass index, body surface area, body shape index and body surface index. In clinical setting the first descriptive parameter is the BMI scale, which provides information about whether an individual body weight is proportionate to the body height. Since the development of BMI, two other body parameters have been developed in an attempt to determine the relationship between body height and weight. These are the body surface area (BSA) and body surface index (BSI). Generally, these body parameters are described as clinical health indicators that described how healthy an individual body response to the other internal organs. The aim of the study is to discuss the use of BSI as a better clinical health indicator for preclinical assessment of body-organ/tissue relationship. Hence organ health condition as against other body composition. In addition the study is `also to determine the best body parameter the best predict other parameters for clinical application. The model parameters are presented as; modeled height and weight; modelled BSI and BSA, BSI and BMI and modeled BSA and BMI. The models are presented as clinical application software for comfortable working process and designed as GUI and CAD for use in clinical application.

STUDIES IN THE SUPPOSED GOITROGENOUS EFFECT OF TAP WATER IN HELSINKI

1960 ◽  
Vol XXXIII (IV) ◽  
pp. 630-636
Author(s):  
F.-E. Krusius ◽  
P. Peltola
Keyword(s):  
Tap Water ◽  
Physiological Saline ◽  
Normal Weight ◽  
The Body ◽  
Iodine Uptake ◽  
Redistilled Water ◽  
Detectable Difference ◽  
Term Administration ◽  
Long Term Experiment

ABSTRACT The study reported here was performed in order to examine the tap water of Helsinki for its alleged goitrogenous effect. In a short-term, 24-hour experiment with rats, kept on an iodine-poor diet, we noticed no inhibition of the 4-hour 131I uptake, as compared with that of animals receiving physiological saline instead of tap water. Two similar groups of rats receiving 1 and 2 mg of mercazole in redistilled water showed a distinct blockage of the 4-hour uptake, which proved the effect of this substance. In a long-term experiment of 5 weeks' duration there was no detectable difference in the body weight, thyroid weight and the 4-hour 131I uptake when the rats receiving tap water or distilled water to which 0.45 per cent of sodium chloride was added were compared with each other. Replacement of tap water by a 10 mg per cent solution of mercazole in redistilled water enlarged the thyroid to double its normal weight and increased the 131I uptake to approximately five times that of the controls. Thus our experiments failed to demonstrate any goitrogenous effect in the tap water of Helsinki. Changes similar to those produced by a long-term administration of mercazole, i. e. an enlargement of the thyroid and an increased thyroidal iodine uptake, have been shown to be due to milk collected from goitrous areas. The observations here reported confirm the importance of milk in the genesis of the goitre endemia of Helsinki. Attention is further called to the fact that a thyroidal enlargement combined with an increased thyroidal iodine uptake cannot always be taken as a sign of iodine deficiency because similar changes may be produced by the administration of goitrogens.

Tenacious Mass Transfer Limitations Drive Catalytic Selectivity during Electrochemical Carbon Dioxide Reduction

2019 ◽  
Author(s):  
Kailun Yang ◽  
Recep Kas ◽  
Wilson A. Smith
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Catalyst Layer ◽  
Active Surface ◽  
Active Surface Area ◽  
High Concentration ◽  
Copper Electrodes ◽  
Surface Enhanced ◽  
Local Current

<p>This study evaluated the performance of the commonly used strong buffer electrolytes, i.e. phosphate buffers, during CO<sub>2</sub> electroreduction in neutral pH conditions by using in-situ surface enhanced infrared absorption spectroscopy (SEIRAS). Unfortunately, the buffers break down a lot faster than anticipated which has serious implications on many studies in the literature such as selectivity and kinetic analysis of the electrocatalysts. Increasing electrolyte concentration, surprisingly, did not extend the potential window of the phosphate buffers due to dramatic increase in hydrogen evolution reaction. Even high concentration phosphate buffers (1 M) break down within the potentials (-1 V vs RHE) where hydrocarbons are formed on copper electrodes. We have extended the discussion to high surface area electrodes by evaluating electrodes composed of copper nanowires. We would like highlight that it is not possible to cope with high local current densities on these high surface area electrodes by using high buffer capacity solutions and the CO<sub>2</sub> electrocatalysts are needed to be evaluated by casting thin nanoparticle films onto inert substrates as commonly employed in fuel cell reactions and up to now scarcely employed in CO<sub>2</sub> electroreduction. In addition, we underscore that normalization of the electrocatalytic activity to the electrochemical active surface area is not the ultimate solution due to concentration gradient along the catalyst layer.This will “underestimate” the activity of high surface electrocatalyst and the degree of underestimation will depend on the thickness, porosity and morphology of the catalyst layer. </p> <p> </p>

Characterisation of production of organic rich topsoil from sludge

2000 ◽  
Vol 42 (9) ◽  
pp. 195-201 ◽  
Author(s):  
P. Andreasen ◽  
P. B. Mortensen ◽  
A. Stubsgaard ◽  
B. Langdahl
Keyword(s):  
Organic Matter ◽  
Oxygen Consumption ◽  
Oxygen Transport ◽  
Mineral Soil ◽  
Climatic Conditions ◽  
Growth Media ◽  
Soil Mixture ◽  
Water Suspension ◽  
Aerobic Process ◽  
Stable Product

The stabilisation of a sludge-mineral soil mixture and a method to evaluate the state of stabilisation were investigated. The organic matter and nitrogen content are reduced up to 50% during a stabilisation process of three months under Danish climatic conditions. The stabilisation was shown to be an aerobic process limited by oxygen transport within the mixture. The degree of stabilisation was evaluated by oxygen consumption in a water suspension and the results showed that a stable product was achieved when oxygen consumption was stable and in the level of natural occurring aerobic soils (0.1 mgO2/(g DS*hr). The study thereby demonstrates that a stability of a growth media can be controlled by the oxygen consumption method tested.

scholarly journals Reduced Graphene Oxide-Supported Pt-Based Catalysts for PEM Fuel Cells with Enhanced Activity and Stability

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 256
Author(s):  
Irina V. Pushkareva ◽  
Artem S. Pushkarev ◽  
Valery N. Kalinichenko ◽  
Ratibor G. Chumakov ◽  
Maksim A. Soloviev ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Surface Area ◽  
Pem Fuel Cells ◽  
Polyol Process ◽  
Proton Exchange ◽  
Active Surface Area ◽  
Electrochemical Performances ◽  
Simultaneous Reduction ◽  
Reduced Graphene

Platinum (Pt)-based electrocatalysts supported by reduced graphene oxide (RGO) were synthesized using two different methods, namely: (i) a conventional two-step polyol process using RGO as the substrate, and (ii) a modified polyol process implicating the simultaneous reduction of a Pt nanoparticle precursor and graphene oxide (GO). The structure, morphology, and electrochemical performances of the obtained Pt/RGO catalysts were studied and compared with a reference Pt/carbon black Vulcan XC-72 (C) sample. It was shown that the Pt/RGO obtained by the optimized simultaneous reduction process had higher Pt utilization and electrochemically active surface area (EASA) values, and a better performance stability. The use of this catalyst at the cathode of a proton exchange membrane fuel cell (PEMFC) led to an increase in its maximum power density of up to 17%, and significantly enhanced its performance especially at high current densities. It is possible to conclude that the optimized synthesis procedure allows for a more uniform distribution of the Pt nanoparticles and ensures better binding of the particles to the surface of the support. The advantages of Pt/RGO synthesized in this way over conventional Pt/C are the high electrical conductivity and specific surface area provided by RGO, as well as a reduction in the percolation limit of the components of the electrocatalytic layer due to the high aspect ratio of RGO.

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