Seasonal fluctuations in river bacteria as measured by multivariate statistical analysis of continuous cultures

1982 ◽  
Vol 28 (8) ◽  
pp. 959-975 ◽  
Author(s):  
Colin R. Bell ◽  
Maxine A. Holder-Franklin ◽  
Mervyn Franklin
Keyword(s):  
Statistical Analysis ◽  
Continuous Culture ◽  
Culture Medium ◽  
Nitrogen Concentration ◽  
Diversity Analysis ◽  
Seasonal Fluctuations ◽  
High Nitrogen ◽  
Continuous Cultures ◽  
Multivariate Statistical ◽  
Nitrogen Concentrations

Forty-eight continuous culture enrichments were performed on summer and winter water samples from two contrasting rivers. The cell output from each chemostat was dependant on the temperature and nitrogen concentration of each enrichment. The diversity of the populations from the continuous cultures, as assessed by species diversity analysis, was always greater than populations obtained on agar plates. However, the species isolated exclusively by continuous culture in these experiments were not unique to the chemostat. All of these species had been isolated at some time on plates directly. High nitrogen concentrations were found to decrease diversity. Populations sampled during the winter were influenced primarily by the concentration of nitrogen. Summer isolates were affected mainly by the temperature of the culture medium. The nutritional versatility of the population was not affected by enrichment of the continuous culture.

Intraseasonal variation in the δ15N signature of taiga trees and shrubs

1998 ◽  
Vol 28 (3) ◽  
pp. 485-488 ◽  
Author(s):  
Knut Kielland ◽  
Bruce Barnett ◽  
Don Schell
Keyword(s):  
Growth Form ◽  
Nitrogen Concentration ◽  
Growing Season ◽  
Isotopic Signature ◽  
Seasonal Fluctuations ◽  
Intraseasonal Variation ◽  
Plant Nitrogen ◽  
Nitrogen Turnover ◽  
Nitrogen Concentrations ◽  
Trees And Shrubs

We examined the stable isotope ratios of nitrogen from six dominant taiga species over three distinct phenological periods during the growing season. Temporal changes in the isotopic signature varied among species, but were not consistent within a given growth form. Despite large variation between nitrogen concentrations in new, mature, and senescent foliage, the seasonal fluctuations in δ15N were small with the exception of aspen, a tree species growing on the most fertile sites. In the absence of strong within-season variation in isotope signature, we conclude that this parameter reasonably well integrates the plant-nitrogen relations over the growing season for most species, with the caveat that this parameter may show significant temporal variation in species from high-nitrogen environments. We found a significant, positive relationship between nitrogen concentration and δ15N values in mature and newly flushed foliage, suggesting that plant enrichment in δ15N is associated with increased soil nitrogen turnover.

scholarly journals Growth and Biochemical Composition of Porphyridium purpureum SCS-02 under Different Nitrogen Concentrations

Marine Drugs ◽  
2019 ◽  
Vol 17 (2) ◽  
pp. 124 ◽  
Author(s):  
Tao Li ◽  
Jin Xu ◽  
Houbo Wu ◽  
Peiliang Jiang ◽  
Zishuo Chen ◽  
...  
Keyword(s):  
Large Scale ◽  
Culture Medium ◽  
Nitrogen Concentration ◽  
Nitrogen Supply ◽  
Arachidonic Acid Content ◽  
Porphyridium Purpureum ◽  
Strong Light ◽  
Commercial Cultivation ◽  
Nitrogen Concentrations ◽  
Low Nitrogen

Microalgae of the genus Porphyridium show great potential for large-scale commercial cultivation, as they accumulate large quantities of B-phycoerythrin (B-PE), long chain polyunsaturated fatty acids (LC-PUFAs) and exopolysaccharide (EPS). The present study aimed to adjust culture nitrogen concentrations to produce Porphyridium biomass rich in B-PE, LC-PUFAs and EPS. Porphyridium purpureum SCS-02 was cultured in ASW culture medium with low nitrogen supply (LN, 3.5 mM), medium nitrogen supply (MN, 5.9 mM) or high nitrogen supply (HN, 17.6 mM). HN significantly enhanced the accumulation of biomass, intracellular protein, B-PE and eicosapentaenoic acid. LN increased the intracellular carbohydrate and arachidonic acid content, and promoted the secretion of EPS. The total lipids content was almost unaffected by nitrogen concentration. Based on these results, a semi-continuous two-step process was proposed, which included the production of biomass rich in B-PE and LC-PUFAs with sufficient nitrogen, and induced EPS excretion with limited nitrogen and strong light.

scholarly journals Orchid in vitro growth as affected by nitrogen levels in the culture medium

2012 ◽  
Vol 30 (1) ◽  
pp. 119-124 ◽  
Author(s):  
Armando R Tavares ◽  
Jorge Luiz M Young ◽  
Sandra S Ori ◽  
Shoey Kanashiro ◽  
Giuseppina PP Lima ◽  
...  
Keyword(s):  
Culture Medium ◽  
Culture Media ◽  
Nitrogen Concentration ◽  
Dry Weight ◽  
In Vitro Cultivation ◽  
Ionic Balance ◽  
In Vitro Growth ◽  
Nitrogen Levels ◽  
Nitrogen Concentrations

In vitro cultivation is the main propagation method for the family Orchidaceae, whereas nitrogen is the most important nutrient in the culture media. This work was carried out to study the influence of different nitrogen concentrations on the in vitro growth of the orchid Phalaenopsis amabilis. Nitrogen concentrations varied by altering the ionic balance of the Murashige & Skoog (MS) culture medium. Plants, 360 days old, were cultivated in liquid MS, modified with 7.5, 15, 30, 45, and 60 mM N. After 180 days, we assessed plant and root length, number of leaves and roots, and fresh and dry weight of leaves, roots and plants. Treatments were assigned to completely randomized plots, with four replications. Plots consisted of five three-plant flasks. The lowest nitrogen level (7.5 mM) in the medium induced root development in length, number, and fresh and dry weight. The concentration 30 mM N stimulated both emission and dry weight accumulation of leaves. The original nitrogen concentration in the MS medium (60 mM) was excessive for the in vitro growth of P. amabilis.

Nitrogen in temperate crop and pasture plants

1975 ◽  
Vol 26 (1) ◽  
pp. 103 ◽  
Author(s):  
JS Gladstones ◽  
JF Loneragan
Keyword(s):  
Nitrogen Concentration ◽  
Trifolium Subterraneum ◽  
Lolium Rigidum ◽  
High Nitrogen ◽  
Pasture Legumes ◽  
Ornithopus Compressus ◽  
Nitrogen Concentrations ◽  
Three Stages ◽  
Erodium Botrys ◽  
Pasture Plants

Nitrogen concentrations were determined in the tops of 24 annual crop and pasture varieties grown together in ungrazed plots on a lateritic gravelly sand at Gidgegannup, W.A., and sampled at three stages during growth and at maturity. All legumes had higher nitrogen concentrations in the tops than all non-legumes, but considerable variation was evident within each group. Among pasture legumes, Ornithopus compressus and O. sativus had the highest concentrations, especially towards maturity, and Trifolium subterraneum cv. Yarloop and Clare the lowest. Nitrogen concentrations in all Lupinus spp. fell rapidly towards maturity, and they were unique in suffering substantial net nitrogen losses from the tops. The herb Erodium botrys grew better and took up more nitrogen under conditions of deficiency than did the grasses. Its nitrogen concentration was nevertheless very low. Among the grasses, Bromus rigidus consistently had the highest nitrogen concentration and Lolium rigidum the lowest. There was some evidence among non-legumes of a correlation between high nitrogen concentrations and/or total uptake and observed adaptation to sandy soils. The superior adaptation of legumes in the experimental environment was demonstrated. It is suggested that crop legumes could make a more important agronomic contribution than hitherto in this and similar environments.

High Nitrogen Concentration in Fe-Cr-Ni Alloys

1991 ◽  
Vol 251 ◽  
Author(s):  
James C. Rawers ◽  
Nev A. Gokcen ◽  
Robert D. Pehlke
Keyword(s):  
High Pressure ◽  
Nitrogen Concentration ◽  
Weight Percent ◽  
Published Data ◽  
High Nitrogen ◽  
Concentration Data ◽  
Statistical Correlations ◽  
Nitrogen Concentrations ◽  
Pressure Melting ◽  
Percent Nitrogen

ABSTRACTIncreasing the nitrogen concentration in iron and iron alloys significantly improves their mechanical properties. A recent technique for melting in a hot-isostatic pressure furnace using nitrogen as the pressurizing gas has been developed by U.S. Bureau of Mines researchers for making massive nitrogen additions to iron (up to 1.6 weight percent nitrogen) and iron-chromium-nickel alloys (up to 6.6 weight percent nitrogen). The total nitrogen concentration measured at atmospheric pressure and room temperature was determined to be the equilibrium nitrogen concentration in the molten alloy. Statistical correlations were derived to explain the effects of melt pressure and alloy composition on the resulting nitrogen concentration. Nitrogen concentrations measured in solidified alloys made by high pressure melting techniques at lower pressures are consistent with previous published data. Computer generated phase diagrams for high nitrogen-chromium concentrations are also consistent with nitride microstructure observed after high-pressure melting. Extension of existing atmospheric nitrogen concentration data to higher pressure nitrogen concentrations shows Sievert's law (nitrogen concentration is proportional to the square root of the nitrogen melt pressure) to be valid for pure iron. However, substantial deviations from Sievert's law are observed for higher alloy compositions. Statistical fits of thermodynamic concentration data to the high-pressure melt nitrogen data requires evaluating element concentration terms, interaction effect terms, pressure terms, and pressure-composition effects terms. Examination of the nitrogen concentration data suggests several methods of correlation.

Statistical Analsysis to Evaluate Heavy Metal Pollution in the Air Obatained by Moss Technique in Hanoi and its Surrounding Region

2019 ◽  
Vol 29 (3SI) ◽  
pp. 411
Author(s):  
N. H. Quyet ◽  
Le Hong Khiem ◽  
V. D. Quan ◽  
T. T. T. My ◽  
M. V. Frontasieva ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Statistical Analysis ◽  
Metal Pollution ◽  
Heavy Metal Pollution ◽  
Principal Component ◽  
Multivariate Statistical ◽  
Five Factors ◽  
Heavy Metal Elements ◽  
Surrounding Areas ◽  
Potential Pollution

The aim of this paper was the application of statistical analysis including principal component analysis to evaluate heavy metal pollution obtained by moss technique in the air of Ha Noi and its surrounding areas and to evaluate potential pollution sources. The concentrations of 33 heavy metal elements in 27 samples of Barbula Indica moss in the investigated region collected in December of 2016 in the investigated area have been examined using multivariate statistical analysis. Five factors explaining 80% of the total variance were identified and their potential sources have been discussed.

Multivariate statistical analysis of elements content in snow cover in Blagoveshchensk

2018 ◽  
Vol 52 (2) ◽  
pp. 15
Author(s):  
V. I. Radomskaya ◽  
D. V. Yusupov ◽  
L. М. Pavlova ◽  
А. G. Sеrgееvа ◽  
N. А. Bоrоdinа ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Snow Cover ◽  
Multivariate Statistical Analysis ◽  
Multivariate Statistical

Multivariate Statistical Analysis Regarding the Formulation of Oxicam-Based Pharmaceutical Hydrogels

2017 ◽  
Vol 68 (4) ◽  
pp. 726-731
Author(s):  
Lenuta Maria Suta ◽  
Anca Tudor ◽  
Colette Roxana Sandulovici ◽  
Lavinia Stelea ◽  
Daniel Hadaruga ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Multivariate Statistical Analysis ◽  
Pharmaceutical Formulations ◽  
Analysis Data ◽  
Multivariate Statistical ◽  
Predictive Variables ◽  
Rapid Release ◽  
Computational Data ◽  
Experimental Protocols ◽  
Formulation Factors

In this paper, it was analysed the influence of formulation factors over obtaining oxicam hydrogels, using the statistical analysis. Data analysis and predictive modeling by multivariate regression offers a large number of possible explanatory/predictive variables. Therefore, variable selection and dimension reduction is a major task for multivariate statistical analysis, especially for multivariate regressions. The statistical analysis and computational data processing of responses obtained from different pharmaceutical formulations, via different experimental protocols, lead to the optimization of the formulation process. It was found that the most suitable pharmaceutical formulations based on oxicams with the possibility of rapid release contained cyclodextrin, in particular 2-hydroxypropyl-b-cyclodextrin.

Anaerobic Semi-Continuous Culture Biodegradation of Dichlorophenols Containing an Ortho Chlorine

1987 ◽  
Vol 22 (3) ◽  
pp. 427-436 ◽  
Author(s):  
S.E. Hrudey ◽  
E. Knettig ◽  
P.M. Fedorak ◽  
S.A. Daignault
Keyword(s):  
Activated Carbon ◽  
Continuous Culture ◽  
Chlorine Atom ◽  
Degradation Process ◽  
Anaerobic Sludge ◽  
Continuous Cultures ◽  
Complete Mineralization

Abstract Rapid and preferential dechlorination of the ortho chlorine from 2,6-, 2,4- and 2,3- dichlorophenol substrates was observed in semi-continuous cultures inoculated with 50% unacclimated anaerobic sludge. The rate of further dechlorination depended on the position of the second chlorine atom. The dechlorination rates for the second chlorine ranked ortho > para > meta. Complete mineralization to methane was only observed in cultures fed 2,6-dichlorophenol. Addition of activated carbon to the anaerobic cultures showed some benefit to the degradation process.

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