نتایج جستجو برای: phosphorus p
تعداد نتایج: 1299810 فیلتر نتایج به سال:
Spatial and temporal variability of phosphorus (P) fractions content in bottom sediments of a shallow preliminary reservoir was studied in Antoninek, situated in Poznań. Fractions were analyzed at least once in a season (more often in spring and summer) between August 2004 and November 2005 according to the fractioning protocol proposed by Psenner et al. (1988). Circa 10 cm thick sediment layer...
The issues of diffuse and point source phosphorus (P) pollution in the Hampshire Avon and Blashford Lakes are explored using a catchment model of the river system. A multibranch, process based, dynamic water quality model (INCA-P) has been applied to the whole river system to simulate water fluxes, total phosphorus (TP) and soluble reactive phosphorus (SRP) concentrations and ecology. The model...
The extraction of soil organic phosphorus by the NaOH-EDTA procedure was assessed in detail for a tropical forest soil (clay-loam, pH 4.3, total carbon 2.7%). Optimum conditions for the quantification of soil organic phosphorus and characterization of its composition by solution P NMR spectroscopy were extraction in a solution containing 0.25 M NaOH and 50 mM Na2EDTA in a 1:20 solid to solution...
Harvests of crops, their trade and consumption, soil erosion, fertilization and recycling of organic waste generate fluxes of phosphorus in and out of the soil that continuously change the worldwide spatial distribution of total phosphorus in arable soils. Furthermore, due to variability in the properties of the virgin soils and the different histories of agricultural practices, on a planetary ...
OBJECTIVE To assess the knowledge of adult hemodialysis patients and nurses working in dialysis units, specifically with regard to knowledge of phosphorus and other nutrients related to dietary management of end-stage renal disease. DESIGN Cross-sectional cohort study. SETTING Hemodialysis unit. SUBJECTS One hundred ninety-one hemodialysis patients and 105 dialysis nurses, as well as 86 c...
We derive the structural principles of polyhedral allotropes of phosphorus, introducing three distinct families of black phosphorus nanostructures. The predicted tetrahedral, octahedral, and icosahedral phosphorus cages can also be considered as phosphorus fullerenes. Phosphorus cages up to P(888) are systematically investigated by quantum chemical methods, and their thermodynamic stabilities a...
To investigate the correlations among seminal plasma Magnesium (Mg), Phosphorus (P), Potassium (K), Calcium (Ca), Chromium (Cr), Manganese (Mn), Iron (Fe), Copper (Cu), Zinc (Zn), Selenium (Se), Molybdenum (Mo) and Iodine (I) concentrations and semen parameters [1– 15]. 500 fertile and 1000 infertile males provided a standardized semen specimen. Total Magnesium (Mg), Phosphorus (P), Potassium (...
The acute effect of i.v. and direct intrarenal arterial infusion of 25-hydroxycholecalciferol (25HCC) and 1,25-dihydroxycholecalciferol (1,25-DHCC) on renal handling of phosphorus was evaluated in the following groups of rats: (a) intact animals, (b) parathyroidectomized (PTX) hypocalcemic rats, (c) PTX rats in which normocalcemia was maintained with calcium supplements and (d) PTX animals in w...
Concern over nonpoint-source phosphorus (P) losses from agricultural lands to surface waters has resulted in scrutiny of factors affecting P loss potential. A rainfall simulation study was conducted to quantify the effects of alternative P sources (dairy manure, poultry manure, swine slurry, and diammonium phosphate), application methods, and initial soil P concentrations on runoff P losses fro...
Drinking-water treatment residuals (WTRs) can immobilize excess soil phosphorus (P), but little is known about the long-term P retention by WTRs. To evaluate the long-term P sorption characteristics of one Fe- and one Al-based WTR, physicochemical properties pertinent to time-dependency and hysteresis of P sorption were assessed. This study also investigated the P sorption mechanisms that could...
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