The Canadian field-naturalist.

v.36 (1922)

The Canadian field-naturalist.

v.33 (1919-1920)

Full-wave field interactions of nonuniform transmission lines

Transmission-line supertheory, generalized transmission-line theory, radiation

Time- and frequency-domain modeling of passive interconncection structured in field and circuit analysis

PEEC, computational electromagnetics

Efeitos do arsênico sôbre a cultura do algodoeiro em terra arenosa

The authors studied the action of arsenic, in the form of lead arsenate and sodium arsenite, on cotton in white sandy soil of Piracicaba, State of S. Paulo, Brazil. The experiment was carried out in Mitscherlich pots, applying increasing quantities of the above mentioned compounds. The following conclusions were reached: sodium arsenite is more toxic than lead arsenate. 48 pounds per acre of lead arsenate and 16 pounds per acre of sodium arsenite reduced the vegetative development and the production of cotton. The roots were more seriously affected than the aerial parts. Sandy soils were sensitive to arsenic toxicity. The arsenic mobilization in the soil seems to depend upon factors such as, the a- cidity, the concentration of Fe2O3, CaO, P2O5 and soil colloids, both clay and humus components. The authors suggest, based on their own experiment and after a detailed study of the literature, the use of organic insecticids which may not leave toxic residues, rotation of crops, application of lime and reduction of arsenical sprays to a mini mum. Arsenic compounds should not be used in soils destined to the cultivation of food plants. Rice should not be planted in soils contaminated by arsenic compounds during several years of cotton cultivation. Future experiments are planed, using other soils such as "terra roxa", in Mitscherlich pots and in field plots.

Geometric distortion correction in EPI at ultra high field

Magdeburg, Univ., Fak. für Naturwiss., Diss., 2012

Arsenicais e inseticidas orgânicos sôbre o algodoeiro em terras roxa e arenosa

The authors carried out a series of pots and plots experiments applying arsenical and organic insecticides to cotton plants cultivated in "terra roxa" and in a sandy soil. The first results were presented in 1947, to the la. Reunião Brasileira de Ciência do Solo (First Brazilian Congress of Soil Science); they pointed out the danger resulting from the accumulation of arsenic in soils due to the constant applications of arsenicais to control cotton pests; in the course of the time, the amount of residual arsenic in the soil would determine a decrease in cotton yield caused by its toxic effect on the crop. The following conclusions were drawn from the last three experiments: 1) the field experiment conducted in a sandy soil to which lead arseniate was applied in increasing rates produced a reduction of 50 per cent in the yield (the three highest doses were responsible for this result); by this way, the pot experiment published in 1947 was confirmed); 2) in the pot experiment with "terra roxa" toxic effects appeared only in the plants receiving the last dosis of lead arsenate; this result is explained quite naturally by a considerable absorption of the AsO4 --- ion by "terra roxa" colloidal material; furthermore the CaO, P2O5 and Fe2O3 content and the pH value (higher) would decrease the arsenate solubilization in the soil considered; 3) the pot experiment with organic insecticides applied in the rates usually employed in the control of cotton pests, showed that 10% D.D.TD. and 2.5% Rotenone did not affect cotton plants cultivated in a sandy soil; however we agree with FOSTER (1951), in the point that both mineral and organic insecticides must be applied in the minimum amount as possible; we also think that experiments like those should be carried out with the known insecticides, in several soil conditions and with many crops in order to determine the maximum limits of tolerancy.

Contribuição ao estudo do «vermelhão» do algodoeiro (Gossipium herbaceum)

During the years 1948, 1949 and 1951 a disease occurred in the cotton crops of the state of S. Paulo Brazil (S. Am.), which caused a severe drop in yields. The abnormality was characterized by a typical reddish - purple color of the leaves, being by this reason, called "vermelhão", that is, reddening of the cotton plant. The disease was associated with a dry season. Among the several hypotheses raised to explain the causes of the disease were: insect attack, potassium deficiency - where from the name "potash hunger" was also given -, and magnesium deficiency: In order to study the problem the Department of Agricultural Chemistry of the College of Agriculture of the University of São Paulo, at Piracicaba, carried out a series of experiments as follows: 1. pot experiments in which soil of one of the affected regions was used ("terra roxa", a red-brownish soil derived from basalt); 2. pot-soil experiments varying the moisture supplied; 3. sand culture experiments omitting certain elements from the nutrient solutions; 4. field plot experiments, conducted on a sandy soil; three different varieties were employed: Texas, Express, and I.A. 817; magnesium was applied either as sulfate or dolomitic limestone. All the experiments were completed with suitable chemical analyses. The results can be summarized as follows: 1. in the first trial, the not properly manured pots (minus Mg), symptoms were registered which were similar to the symptoms observed in the field; it was possible to establish some differences among three different types of reddening: due to lack of K in the mixed fertilizers used, the characteristic cotton rust made its appearance, the red color in the leaves of the minus Mg plants was all alike that described in the current literature as a symptom of Mg-deficiency; in all the treatments ocurred a yellow-reddish color in the leaves associated with the latest stages of maturity; 2. in the second experiment it was verified that when the plants in the pots with soil were kept 75 per cent of the water holding capacity, no symptom of deficiency showed up; was true even for the plants not receiving neither K nor Mg; however, plants supplied with only 25 per cent of the water holding capacity showed, respectively, cotton rust in the minus K treatment and the red purplish color in the minus Mg series; 3. the sand culture experiment confirmed lack of Mg as the cause of "vermelhão", being potash deficiency the responsible for cotton rust; 4. in the field experiment, variety LA. 817 revealed to be the most sensitive to "vermelhão" when Mg was omitted from the fertilizers; symptoms of K deficiency appeared when no K was supplied; both magnesium sulfate and dolomitic limestone proved to be equally effective in the control of "vermelhão"; 5. the analyses of material collected both in the field as well in the pots revealed that leaf petiole in the most reliable part to indicate the K and Mg status of the plant; the variation in Mg content suffered by the plants showing different stages of "vermelhão was, quantitatively, at least as large as that in K content, however when one deals with K deficient plants, that is, plants showing the typical rust, no variation occurred in the Mg content, whereas K in the dry mater dropped from more than 1 per cent to less than half per cent. Then, the following general conclusions can be drawn: 1. Mg deficiency is the cause of "vermelhão" of cotton crops; 2. K deficiency also occurred, but in a lesser degree; 3. the climate conditions - especially the lack of rain influenced the soil dynamic of K, and especially Mg, bringing a severe reduction in their assimilability; 4. the "vermelhão" disease can be easily controlled upon additions either of magnesium sulfate or dolomitic limestone.

Publications of Field Museum of Natural History.

Fieldiana. Botany, v. 13, part 2

Useful plants and drugs of Iran and Iraq / by David Hooper. With notes by Henry Field.

v.9:no.3(1937)

Design, modeling and control of an autonomous field robot for white asparagus harvesting

Magdeburg, Univ., Fak. für Maschinenbau, Diss., 2014

Publications of Field Museum of Natural History.

Fieldiana. Botany series v. 11, index

Proceedings of the Cotteswold Naturalists' Field Club.

v.2 (1854-1860)