Phosphorus

About: Phosphorus is a research topic. Over the lifetime, 53120 publications have been published within this topic receiving 939731 citations. The topic is also known as: element 15 & P.

A nutrient budget of some intensive marine shrimp ponds in Thailand

Abstract: . A mass balance was constructed for nutrient flow through intensive marine shrimp ponds in which budgets for nitrogen and phosphorus were determined for a series of ponds in southern Thailand over two or three culture cycles. Ninety-five per cent of the nitrogen and 71% of the phosphorus applied to the ponds was in the form of feed and fertilizers. Of the feed input (at a food conversion ratio of 2) only 24% of the nitrogen and 13% of the phosphorus was incorporated into the shrimp harvested, whilst the remainder was retained in the pond and ultimately exported to the surrounding environment. The effluent water contained 35% of the nitrogen and 10% of the phosphorus discharged. Of the N and P exported in this effluent, 63–67% occurred during routine water exchange and the remainder during drainage on harvest. A major portion of the nitrogen (31%) and most of the phosphorus (84%) was retained in the sediments, emphasizing the importance of the correct removal and disposal of sediments between crops. Pond age (between two and six production cycles) did not markedly affect nutrient flows, whilst increasing stocking density increased the quantity of nutrients, but not their relative proportions. The results derived from the nutrient budget provide data which may help define effective management techniques for reducing potentially harmful nutrient levels within intensive shrimp ponds, and for reducing the discharge of nutrients to the local environment. The data may also assist in determining the carrying capacity of an area for shrimp farming, and the potential impact of its development on the environment.

An automated procedure for the simultaneous determination of calcium and phosphorus.

Abstract: A completely automated method for the simultaneous or individual determination of calcium and phosphorus in serum and urine without preliminary sample treatment is reported. Separation of calcium and phosphorus from interfering materials is achieved by dialysis under acid conditions. The dialyzed calcium is determined colorimetrically using a metal complexing dye (cresolphthalein complexone) in an alkaline medium. Magnesium, phosphate, citrate, sulfate, etc., did not introduce significant errors under the test conditions. Inorganic phosphorus is determined by a modified Fiske-SubbaRow procedure. Reproducibility and recovery data as well as comparisons with manual methods are presented.

Phosphorus-31 Nmr Spectroscopy in Stereochemical Analysis

Abstract: General Experimental Techniques and Compilation of Chemical Shift Data Empirical Methods for Interpreting Chemical Shifts of Phosphorus Compounds Special Experimental Techniques in Phosphorus NMR Spectroscopy Oriented Phases Theoretical Considerations: Calculations of the Chemical Shift Theoretical Considerations: Spin-Spin Coupling NMR Studies of the Stereochemistry and Fluxionality of Five- and Six-Coordinate Phosphorus Compounds Mechanisms of Reactions of Phosphorus Compounds Conformation and Stereochemistry of Cyclic Compounds Higher Order 31P NMR Spectra of Polyphosphorus Compounds Stereospecificity in 31P-Element Couplings: Proton-Phosphorus Couplings Stereospecificity in 31P-Element Couplings: Phosphorus-Carbon Coupling Stereospecificity in 31P-Element Couplings: One-Bond Couplings to Other Nonmetals and to Metals Stereochemistry of Metal Complexes: Unidentate Phosphorus Ligands Stereochemistry of Metal Complexes: Polydentate Phosphorus Ligands Stereochemistry of Metal Complexes: Phosphido Bridging Ligands Unusual Ligation Modes of Phosphorus Compounds: One- and Two-Coordinate Phosphorus Compounds Unusual Ligation Modes of Phosphorus Compounds: Phosphorus Ylides Unusual Ligation Modes of Phosphorus Compounds: Phospholes Unusual Ligation Modes of Phosphorus Compounds: Phosphoranides Index.