Rate Of Nutrient Absorption Research Articles

Relationship of ion absorption to growth rate in taiga trees.

Rates of nutrient absorption were measured on excised roots of taiga tree seedlings grown in the laboratory. Phosphate and to a lesser extent ammonium (relatively immobile ions in the soil) were absorbed most rapidly by poplar and aspen, two species with rapid growth rates and most slowly by alder and/or black spruce, species with slow growth rates. In contrast, potassium (which is more mobile in soil) was absorbed most rapidly by slowly growing species. All species had low rates of nitrate and chloride absorption. Absorption rate of each ion was most temperature sensitive in those species that typically occupy the warmest soils (i.e. poplar and aspen). We suggest that in infertile soils a high capacity for uptake is an important component of root competition only in the case of mobile ions (e.g. potassium, nitrate), because only for these ions do diffusion shells of adjacent roots overlap; in contrast plants compete for immobile ions (e.g. phosphate) only by increasing absorptive surface via root growth or mycorrhizal association.

Temperature influences nutrient absorption and uptake rates of bananas grown in controlled environments

We explored the influence of temperature on the concentration of nutrients in banana plants, the nutrient uptake rate, apparent root transfer coefficient ( \\ ̄ ga) and the relationship between accumulation of dry matter and nutrient. Young banana plants ( Musa (AAA group, Cavendish sub-group) ‘Williams’) were grown at six temperature regimes (17/10–37/30°C) in sunlit growth chambers for 12 weeks. The amount of nutrient absorbed was influenced by the amount of growth made, but the link between the two differed from one element to another. Temperatures less than 29 22° C reduced the concentration of all elements in the whole plant, except Fe. Temperature influenced the root uptake rate of B 10-fold; K, Na, Ca, Fe and Zn 3–4-fold; and N, P, Mg, Mn, Cu, Cl 1–2-fold. Among the elements the highest recorded rate was 12 mg g −1 day −1 for K at 33 26° C . The optimum temperature for nutrient uptake rates differed among the elements. This was accounted for largely by greater growth at those temperatures of organs with high concentration of particular elements. The \\ ̄ ga (an estimate of efficiency of uptake) of B varied 12-fold among treatments; K, Ca, Mg, Na, Mn, Zn and Cl varied 3–5- fold and N, P, Cu and Fe varied 2–3-fold. The ratio of relative nutrient accumulation rate, R m, to the relative growth rate, R w, was most stable across temperatures for N and least stable for B and Na. However, the trend was for R m R w to increase as temperature rose, indicating an absorption of nutrients greater than might be expected from a change in growth rate as temperature increased, and a decreased efficiency in their utilization for plant growth.

Digestive adaptations for fueling the cost of endothermy.

Little is known about the digestive adaptations that enable mammals to sustain metabolic rates an order of magnitude higher than those of reptiles. Comparison of several features of digestion in mammals and lizards of similar size eating the same diet revealed that mammals processed food ten times faster and with the same or greater extraction efficiency. Transport kinetics and rates of nutrient absorption normalized to the quantity of intestinal tissue were similar in these two classes of vertebrates. The main basis for faster absorption in mammals is their much greater intestinal surface area.

Plant fiber and blood pressure.

Vegetarians and other persons with high fiber intakes have lower average blood pressures than persons with low fiber intakes. We assessed blood pressures in 12 nonobese, insulin-treated, diabetic men on control diets and high carbohydrate and fiber (HCF) diets. The control diets provided 20 g/d of plant fiber, whereas the HCF diets provided 65 g/d. The insulin doses required to maintain satisfactory glycemic control were 73% lower with HCF diets than with control diets. Average blood pressures were 10% lower (p less than 0.01) with HCF diets than with control diets. In a study of six additional men, fecal water excretion was twofold greater with HCF diets than with control diets. Alterations in gastrointestinal function, nutrient absorption rates, and secretion of gastrointestinal and pancreatic hormones may influence blood pressure. The possible antinatriuretic effects of insulin may influence blood pressure responses to fiber intake. Further studies are needed to assess critically the effects of fiber intake on blood pressure.

Long-term nutrient absorption rates and competition between ions in banana in relation to supply of K, Mg and Mn

To provide data on the diagnosis and correction of deficiencies of K, Mg and high Mn experienced in the banana plantations of New South Wales, a sand culture experiment, in 1 m3 containers, was conducted using ‘Williams’ banana. Here we report the effects of K, Mg and Mn treatments on plant and root uptake rates of N, P, K, Ca, Mg, Na, Mn, Cu and Zn and the interaction beween K, Mg and Mn. Increased K supply increased the plant uptake rate of K and P whereas N, Ca, Mg and Cu were decreased. There was no large overall effect of Mg supply on the uptake of elements other than Cu. Within the K series the proportion of roots decreased as K supply increased and the root uptake rate of K, Mg, Mn and Cu was proportional to the concentration in the external medium. For other elements uptake was influenced more by demand within the plant. High Mn supply reduced the uptake of Ca, Mg and Zn but had little effect on the other elements. Values of root uptake rate were only 10% of those reported on other crops, but our data apply to a long time period (~ 1300 days). K and Mn non-competitively inhibited Mg uptake. The K/(Ca + Mg) ratio of the lamina was unable to distinguish between K and Mg deficiency as it did not show an optimum relationship with yield.

Nutrient Film Technique における培養液温がトマトの生育, 収量, 養分吸収に及ぼす影響

Using the recently developed Nutrient Film Technique, growth, fruit yield and nutrient absorption were studied with tomato plants grown at different solution temperatures.Within the range from 15°C to 30°C, higher solution temperatures encouraged nutrient absorption and growth rates of shoot and root. Although solution temperature had little influence on total fruit yield, the percentage of marketable fruits seemed to increase with decreasing solution temperature; 20°C solution producing the highest marketable fruit yield.The occurrence of blossom-end rot, found to increase with increasing solution temperature, could not be explained by calcium absorption or calcium content in the leaves.The ambient temperature in summer was found to have negligible influence on the temperature of solution circulating in the present system. Solution supply, at the rate of 2 litres per plant per hour, being carried out for 15 minutes per hour, was found to provide adequate nutrition and sufficient dissolved oxygen.

The synthesis of models to describe metabolism and its integration.

The wide range of metabolic, nutritional and physiological information which must be integrated in analyses of animal metabolism and function indicates that modelling techniques can be utilized and contribute to the research process. Advantages gained through the use of modelling techniques in support of research include evaluations of available concepts and results for adequacy as quantitative and dynamic explanations of the behaviour of complex (metabolic, physiological) systems, evaluation of alternate hypotheses for probable adequacy, interpretation or extension or both of available information, and identification of critical experiments. Achievement of these objectives requires a close interaction of modelling and experimental analyses. Additional requirements imposed by these objectives are that the elements of research models represent specific biological entities (model must be causal), that the basic models be firmly based on established principles and contain no hypothetical elements, and that numerical inputs to the model derive directly from experimental measurements. Emphasis in developing this presentation was placed upon illustration of these principles and objectives of research modelling. Examples were drawn from three ongoing modelling analyses; animal metabolism, animal growth, and tissue metabolism. Models of whole animal metabolism The development of early models of animal metabolism required extensive searches of the literature and summarization and integration of a wide range of information. Results utilized included estimates of organ weights and energy expenditures, extracellular and intracellular pool sizes of metabolites, nutrient absorption, turnover and utilization rates, and oxidation rates of metabolites (Smith, 1971; Smith et al. 1975). Mathematical representations of tissue metabolism require consideration of energy requirements for basal metabolism and for variable biosynthetic and work functions, affinities of tissues for metabolites, biosynthetic and oxidative capacities of tissues and specific regulatory mechanisms. A generalized equation set for a typical tissue expressed in a modified FORTRAN format follows: DADP=ATPUSE- METOX:SATP,

Foliar Fertilization of Soybeans: Absorption and Translocation of 15N‐Labeled Urea1

AsbtractFoliar fertilization offers a possible means of increasing soybean (Glycine max (L.) Merr.] yields, but little is known of the utilization efficiency of foliar‐applied nutrients. Field experiments were conducted in 1976 and 1977 to determine percentage recovery of foliar applied 15N‐labeled urea by soybeans and translocation of 15N within the plant. Foliar treatments containing N, P, K, S or P, K, S were applied four times during growth stages R‐5 to R‐7. Urea, potassium polyphosphate and potassium sulfate were used to supply 84 + 9 + 28 + 5 kg/ha of N + P + K + S, respectively. The P, K, S treatment was similar except that urea was excluded.In 1976, the two foliar treatments tested on the cultivar ‘Williams’ did not result in a significant increase in seed yieId over the control value of 3,294 kg/ha. In 1977, using the cultivar ‘Kent,’ the N, P, K, S treatment resulted in a significant yield increase of 1,045 kg/ha over the control value of 3,203 kg/ha. Results from the P, K, S treatment, although consistently higher than control values, were not significantly different at the 5% level in either year. Of the total 15N applied, 44 and 67% were recovered in the plants in 1976 and 1977, respectively. Approximately 94% of the recovered 15N ultimately was found in the seed. A maximum of 0.7 kg/ ha of the fertilizer N was translocated to the roots.In a separate experiment, (15NH4)2SO4 was sidedressed at the rate of 112 kg N/ha at weekly intervals to different experimental units during late R‐4 to R‐7 stages. The uptake of 15N decreased from 39 kg/ha with the first application to 19 kg/ha with the last application, but the rate of 15N uptake did not change appreciably with time. Total N in the plants was not influenced by the (15NH4)2SO4 applications. The data indicated that changes in the rate of nutrient absorption by roots during pod‐fill were minimal and unlikely to be a major factor in determining the effectiveness of foliar fertilization.

Seasonal size changes in certain diatoms and their possible significance

Cell sizes of two species of diatoms, Stephanodiscus astraea and Asterionella formosa, were determined in algal populations in four water bodies at various times of the year. Changes in the average cell diameter or length were observed throughout the growing seasons. The possible effects of these cell size changes are discussed in relation to parameters such as rate of sinking, nutrient absorption, temperature, viscosity and turbulence.

Intestinal absorption of L-methionine and glucose in chickens with aflatoxicosis

Graded doses of dietary aflatoxin (1.25, 2.5 and 5 μg/g) fed to broiler chicks for 3 weeks did not affect subsequent in vitro absorption of methionine and glucose by the intestine, compared with contol birds receiving no aflatoxin. A dietary level of 10 μg/g produced a significant increase in the absorption rate of both nutrients. Inhibition studies showed that both the mediated and diffusion components of absorption were increased with 10 μg/g. A prolonged exposure to aflatoxin was necessary for the effect since birds fed toxin for 1 week only (2 to 3 weeks of age) absorbed methionine and glucose at the same rate as controls receiving no aflatoxin.

The response to phosphate of two annual pasture species. II.* The specific rate of uptake of phosphate, its distribution and use for growth

Subterranean clover and Wimmera ryegrass were grown in pots at a range of levels of applied phosphate for up to 33 days after emergence. From the results of sequential sampling, the rates of uptake of phosphate, its distribution and its effect on the rate of assimilation were calculated. The assumption involved in the widely used approximate method for calculating the average specific absorption rate (SAR) of nutrients by roots was found to be invalid. Hence instantaneous values of SAR were calculated from multiple regressions which allowed the simultaneous determination of the effects of phosphorus level and of time. For both species, SAR increased until about 2 weeks after emergence, and then declined. The effect of level of application on SAR differed between the species. For the ryegrass, SAR increased with phosphate level and reached a maximum value. For the clover, there was a level of application below which phosphate was almost ineffective. Above this level, the slope of the relationship between SAR and phosphate applied increased with increasing level of phosphate. It is suggested that this upward-curving relationship occurred because the proportion of added phosphate in the soil solution increases with increasing phosphate level. There was no evidence of a maximum value of SAR for the clover within the range of levels of phosphate used. At all levels of application, the SAR for the clover was lower than that for the grass. Ryegrass transferred a greater proportion of the phosphate to the tops than did clover. The net photosynthetic effectiveness of the tops of both species increased with phosphate concentration. The ryegrass had higher values for photosynthetic effectiveness than the clover at high phosphate concentration. At low phosphate levels the ryegrass allocated a greater proportion of its growth to roots than did the clover. *Part I, Aust. J. Agric. Res., 26: 137 (1975).

The Dynamics of Dry Matter and Chemical Substances in a Juncus effusus Population

Seasonal changes in standing crops of living and dead dry matter and tissue levels of chemical substances were determined for a Juncus effusus population. These data were used to determine rates of production, pigment synthesis and nutrient absorption during different parts of the annual growth cycle. The annual cycle began with the appearance of young shoots in late summer. Net productivity was greatest during early autumn and midspring. Little growth occurred during the winter and there was a rapid dieback of shoots in the summer. Tissue concentrations of most chemical constituents declined during spring growth and summer dieback. Uptake rates of mineral nutrients other than nitrogen were large during autumn growth, but slight during spring growth. The same was true of pigment synthesis. Energy accrual was generally proportional to dry-matter increases during both phases of growth. Results of this investigation and previous studies are discussed to show that rates of net nutrient uptake and synthesis of pigments are not merely functions of net dry-matter production, but physiological characteristics of the species. Quantities of chemical substances per unit area of stand did not necessarily follow the same patterns of change as did dry-matter standing crops. Dead Juncus effusus shoots decomposed rapidly, about 50% of the dry matter disappearing within 4 months. Mineral nutrients were lost more quickly than the degradation of dry matter. INTRODUCTION Herbaceous vegetation of fresh-water marshes often produces large quantities of biomass (Penfound, 1956; Westlake, 1963). Chemical analyses have been made on several marsh species (Straskraba, 1966; Lawrence, 1968; Boyd, 1968, 1970a). These data were used to estimate amounts of chemical constituents per unit area of plant stand and to compare the nutritive value of various species. In addition, a few studies have dealt with the dynamics of mineral nutrient uptake and biochemical synthesis during growth and nutrient losses during decomposition. Uptake rates and tissue concentrations of most minerals declined as the growing season progressed, but maximum mineral accrual per unit area of stand was obtained at or near the time of peak standing crop (Stake, 1967, 1968; Boyd, 1969, 1970b). Pigment concentrations followed a similar trend of change (Boyd, 1970b). Drymatter standing crops decreased during late summer and total quantities of nutrients per m2 declined even faster than dry matter (Boyd, 1969, 1970b). There is very rapid release of most minerals, particularly cations, from emergent macrophytes once the shoots fall into the water (Boyd, 1970c). These processes are obviously very important aspects of the physiological ecology of macrophytes and additional research is needed. The present study was undertaken to describe the patterns of change in tissue concentrations and quantities per unit area of minerals, pigments and energy in a Juncus effusus L. stand during a yearly 1 This research was supported by contract AT (38-1) -310 between the U.S. Atomic Energy Commission and the University of Georgia.

A Study of the Rate and Efficiency of Nutrient Absorption (KNO3) by Tomato Seedlings1

Abstract The application of KNO, to pre-starved tomato seedlings growing in pots resulted in increases in nutrient content (K and N) in the whole plant of 20 - 90% within 6 hr and up to 400% in 7 days. Plants raised in a relatively rich nutritional environment were more efficient in absorbing applied fertilizer than those raised at a lower nutritional level. Healthy vigorous plants responded to a moderate application of applied KNO3 by absorbing almost all of it. Larger applications did not result in more absorption, which suggests a control mechanism in the plant.

Effect of Coccidial Infection Upon Passage Rates of Digestive Tract Contents of Chicks

CHANGES in the rate of passage of nutrients through the digestive tract may affect the amount of nutrients absorbed by altering the period of time during which digestion and absorption take place. These effects, then, could provide a partial explanation of the effects of various coccidial infections upon nutrient absorption as reported by Turk and Stephens (1966, 1967a, b, c). Schildt and Herrick (1955) have observed stasis of the gut occurring during the period of severe Eimeria tenella infections. An earlier report (Levine and Herrick, 1954) described an impairment of skeletal muscle responses to stimuli during the severe stages of this infection. If the stasis and impairment of motility resulted in significantly slower rates of food passage through the gastrointestinal tract, more time would be allowed for more complete digestion of food materials and for more complete absorption of nutrients from the gut into the bloodstream. Since nutrient absorption rates .

Respiration and Nutrient Absorption of Plant Roots Growing under Aerobic or Anaerobic Condition : 2. Respiration and nutrient absorption of rice roots growing under aerobic condition

Attached roots and detached roots of rice plants were examined for the rates of respiration and nutrient absorption under an aerobic condition, adopting the methods stated in the previous reports. The results obtained may be summarized as follows; 1. There were no marked differences in the rates of respiration and nutrient absorption of attached roots whether they were kept under an aerobic condition or not. 2. When detached roots were exposed to an aerobic coditon, they carried on almost normal respiration being followed by promotion of nutrient uptake, comparing with those exposed to an anaerobid condition. But they took up less amount of nutrients than attached roots in spite of the rate of respiration being rather accelerated. That may be the reason why detached roots were kept under conditions disadvantageous to nutrient absorption, as stated in the previous report. Besides, some othe reason was considered. 3. In case NaN3 was added to the culture solution, the rates of respiration and nutrient uptake both of attached and detached roots were severely depressed even if they were kept under an aerobic condition. 4. Attached roots showed a strong oxidizing power whether they were kept in an aerated or nonaerated medium. In contrast the oxidizing power of detached roots was decreased markedly when they were kept in a non-aerated medium, although they could reveal an oxidizing power as strong as that of attached roots when kept in an oxygenated medium. The oxidizing power of both kinds of roots which had been grown in the culture solution containing NaN3 was always depressed whether they were kept in an aereted mediun or not. 5. From the results stated above as well as those reported in the previous papers, it may be concluded that the roots of rice plants can perform almost normal respiration and nutrient absorption even if they are exposed to a poorly oxygenated medium so for as no substances harmful to respiration are present there. Because the rice roots can receive molecular oxygen enough to sustain aerobic respiration from the the tops through the well-developed ventilating system.

Respiration and Nutrient Absorption of Plant Roots Growing under Aerobic or Anaerobic Condition : 1. Respiration and nutrient absorption of rice roots growing under anaerobic condition.

Attached roots and detached roots of rice plants were kept submerged for 8 hours in a culture solution to which nitrogen gas was bubbled. The amount of CO2 evolved from respiration was analyzed in 1-hour period by way of absorbing CO2 in N/50 KOH solution. Before and after the experiment, nutrients solved in the culture solution were measured to determine the amount of nutrients absorbed by the roots. The components analyzed were NH4-N, P2O5, K2O, and CaO. The results obtained are summarized as follows: 1. The rates of respiration and nutrient absorption of attached roots kept submerged in the culture solution to which nitrogen gas was bubbled were almost nearly the same as normal, while a considerable depression in the rate of respiration and a marked decrease in nutrient absorption were revealed when 10-2M NaN3 was applied to the culture solution. 2. The rates of respiration and nutrient absorption of detached roots were far less than those of attached roots, when they were treated with nitrogen gas without addition of NaN3 to the culture solution, but they were nearly the same rates as those of attached roots kept submerged in the culture solution containing 10-2M NaN3. A tendency of somewhat accelerated depression in the rates of respiration and nutrient absorption was seen, providing detached roots were exposed to the culture solution containing 10-2M NaN3. 3. Resting on the facts obtained from this experiment it should be inferred that the intact rice roots are able to sustain aerobic respiration and to absorb nutrients quite normally under anaerobic condition so far as any materials harmful to respiration are not included in the solution and, eventually, that molecular oxygen may be transported from the top to the roots of rice plants through the well-developed ventilating system.

Influence of Drainage on the Growth of Rice Plant in Rice Field. : I) Effect of drainage of surface water on the growth, yield and nutrient uptake of rice plant

The experiment was made to evaluate the effect of drainage of surface water on the growth, yield and nutrient uptake of rice plant. Rice plants were grown in both submerged and drained conditions. The water level in the submerged plots was maintained at 5 cm depth through the growing season. In contrast, the drained plots were kept under wet condition (no standing water) from one week after transplanting to harvesting time. Both plots mentioned above included much and less fertilization, each with powdery, granular fertilizer and soybean cake, respectively. The results obtained were as follows. 1) The drained plots, as compared with the submerged plots, generally showed the increased number of tillers in both tillering and booting stages, and the decreased number of panicles at harvest. The weight of dry matter per hill in the drained plot became to be inferior to that in the submerged plot as the rice plant grew, especially in the case of less fertilization. 2) It was found that the amounts of N, P2O5, K2O and SiO2 absorbed by rice plant were commonly decreased by the draining, but in some cases were temporarily increased at tillering stage. The absorption rate of nutrients of rice plant in the drained plots decreased remarkably in the case of less fertilization. 3) The grain yields in the submerged plots were higher than those in the drained plots, except for the much fertilization plots with granular fertilizer. In general, the reduction of grain yield by the draining were less in the much fertilization than in the less fertilization and less in granular than in powdery and soybean cake. Thus, it is suggested that the reduction of the grain yield in the drained plots are depend chiefly on the decrease of the nutrient uptake of the rice plant at later stage of growth, because the long time drainage decreases availability of N, P2O5, SiO2 etc. in soil.

Composição química do feijoeiro e absorção de elementos nutritivos, do florescimento à maturação

Procedeu-se a um estudo das curvas de produção de matéria sêca, concentração e absorção de elementos minerais, no feijoeiro. Plantas da variedade Chumbinho opaco, crescendo nas condições de campo, com e sem adubação, foram colhidas em diferentes estádios do ciclo, a partir do florescimento. Dividiram-se as amostras em raiz, haste, fôlha e fruto, submetendo-as à análise quantitativa de N, P, K, Ca, Mg e S. Na planta madura, as sementes foram colhidas e analisadas separadamente da vagem. São também discutidos os efeitos provocados pela adubação sôbre aquelas características e a extração de nutrientes do solo pelo feijoeiro, na colheita, levando-se em conta o retôrno ou não dos resíduos de cultura. Os dados oferecem, ainda, indicações quanto à aplicação tardia de nitrogênio no feijoeiro, com base no fato de que uma absorção ativa de nitrogênio pela planta ocorre durante o período critico de crescimento das sementes, quando se intensifica a produção de carbohidratos. Nesta fase, a demanda da planta poderia não ser satisfeita à custa exclusiva do N fixado pelo processo simbiótico.

Chicks Prefer Fat-Supplemented Diets

The supplementation of broiler diets with fat has been shown to improve feed efficiency by the following: Siedler and Scheweigert (1953), Yacowitz (1953), Carver el al. (1954), Donaldson el al. (1954), and Runnels (1955).Sunde (1954) attributed the effectiveness of fats in improving feed efficiency to the utilization of the glycerol portion of the fat molecule. It has been suggested that varying rates of nutrient absorption may contribute to improved feed utilization. In view of the lack of information on palatability, the experiment reported herein was designed to determine whether any preference could be shown for either fat-supplemented or nonsupplemented diets as manifested by the amount of feed consumed by chicks from 1 to 8 weeks of age.One hundred twenty-three straight run White Wyandotte x White Rock day-old chicks were fed the Kansas State College all-vegetable protein high efficiency basal diet plus Aurofac* (chlortetracycline) in a wire floored battery …

The Time and Rate of Nutrient Absorption by Flue‐Cured Tobacco1

Agronomy JournalVolume 34, Issue 4 p. 327-339 Article The Time and Rate of Nutrient Absorption by Flue-Cured Tobacco1 A. L. Grizzard, A. L. GrizzardSearch for more papers by this authorH. R. Davies, H. R. DaviesSearch for more papers by this authorL. R. Kangas, L. R. Kangas Associate Agronomist and Research Fellows, respectively. The writers are indebted to the Ammonia Department of the E. I. DuPont de Nemours Company, Inc., for the fellowship awards to the Agronomy Department which made this work possible. Thanks are extended to E. M. Matthews of the Pittsylvania County Station for assistance with the field work required in connection with the study.Search for more papers by this author A. L. Grizzard, A. L. GrizzardSearch for more papers by this authorH. R. Davies, H. R. DaviesSearch for more papers by this authorL. R. Kangas, L. R. Kangas Associate Agronomist and Research Fellows, respectively. The writers are indebted to the Ammonia Department of the E. I. DuPont de Nemours Company, Inc., for the fellowship awards to the Agronomy Department which made this work possible. Thanks are extended to E. M. Matthews of the Pittsylvania County Station for assistance with the field work required in connection with the study.Search for more papers by this author First published: 01 April 1942 https://doi.org/10.2134/agronj1942.00021962003400040004xCitations: 5 1 Contribution from the Department of Agronomy, Virginia Agricultural Experiment Station, Blacksburg, Va. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume34, Issue4April 1942Pages 327-339 RelatedInformation