Transformation of15N-labelled urea and its modified forms in tropical wetland rice culture

AbstractSilicate slags are one of the most widely used silicon (Si) source in agriculture. Even though the agronomic significance of slags has been demonstrated in several crops, only a few attempts were made to evaluate these Si sources based on their chemical composition. The main objective of this study was to characterize different silicate slags based on their chemical properties and to explore the effect of these chemical properties on the yield, and Si uptake in wetland rice, and dissolution of Si into the soil. Slags were characterised for pH, calcium and magnesium content (alkalinity, A), silicon content, 5 day Na2CO3 + NH4NO3 extractable Si content, and alkalinity to Si ratio (A/Si). Greenhouse and incubation experiments were also conducted using different silicate slags and wollastonite applied at the rate of 300 kg Si ha−1. Slags with A/Si < 3 were found to be ideal Si sources for the economic production of wetland rice and found consistent in increasing soil Si content and rice Si uptake. We conclude that the A/Si ratio of slags can be used as an important parameter to assess the agronomic efficiency of silicate slags in wetland rice.

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A Comparative Analysis of Fractional-Order Gas Dynamics Equations via Analytical Techniques

Mathematics ◽

10.3390/math9151735 ◽

2021 ◽

Vol 9 (15) ◽

pp. 1735

Author(s):

Shuang-Shuang Zhou ◽

Nehad Ali Shah ◽

Ioannis Dassios ◽

S. Saleem ◽

Kamsing Nonlaopon

Keyword(s):

Homotopy Perturbation Method ◽

Graphical Representation ◽

Analytical Techniques ◽

Variational Iteration Method ◽

Computational Techniques ◽

System Of Nonlinear Equations ◽

Gas Dynamics Equations ◽

Homotopy Perturbation ◽

Fractional System ◽

Modified Forms

This article introduces two well-known computational techniques for solving the time-fractional system of nonlinear equations of unsteady flow of a polytropic gas. The methods suggested are the modified forms of the variational iteration method and the homotopy perturbation method by the Elzaki transformation. Furthermore, an illustrative scheme is introduced to verify the accuracy of the available techniques. A graphical representation of the exact and derived results is presented to show the reliability of the suggested approaches. It is also shown that the findings of the current methodology are in close harmony with the exact solutions. The comparative solution analysis via graphs also represents the higher reliability and accuracy of the current techniques.

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Blood Circulation in Insect Wings

The Canadian Entomologist ◽

10.4039/ent9698-1 ◽

1964 ◽

Vol 96 (1-2) ◽

pp. 98-98 ◽

Cited By ~ 2

Author(s):

J. W. Arnold

Keyword(s):

Blood Circulation ◽

The Body ◽

Insect Wings ◽

Wing Structure ◽

Wing Veins ◽

Taxonomic Groups ◽

Modified Forms ◽

Surrounding Membrane

Despite their inert appearance, the wings of insects are living appendages and are supplied with blood. This is true for definitive wings as well as for developing ones, and for modified wings such as tegmina, elytra, hemelytra, and halteres as for those that are specialized for flight. Typically the blood circulates only through the wing veins, but in some insects it escapes into the surrounding membrane in certain areas, and in highly modified forms it may be entirely unconfined. The course of circulation is basically the same in the wings of most insects. It flows outward from the body in the costo-medial veins, moves toward the posterior margins via cross-veins, and returns to the body through the cubito-anal veins and axillary cord. However, rhe precise route followed is highly variable concomitant with distinctive patterns of venation in different taxonomic groups and with wing structure. This is illustrated for a number of orders.

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