scholarly journals Microbial Interactions as Drivers of a Nitrification Process in a Chemostat

2021 ◽  
Vol 8 (3) ◽  
pp. 31
Author(s):  
Pablo Ugalde-Salas ◽  
Héctor Ramírez C. ◽  
Jérôme Harmand ◽  
Elie Desmond-Le Quéméner
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Microbial Ecology ◽  
Mathematical Analysis ◽  
Microbial Interactions ◽  
Genetic Sequencing ◽  
Optimal Tracking ◽  
Operational Taxonomic Units ◽  
Volterra Models ◽  
Nitrification Process

This article deals with the inclusion of microbial ecology measurements such as abundances of operational taxonomic units in bioprocess modelling. The first part presents the mathematical analysis of a model that may be framed within the class of Lotka–Volterra models fitted to experimental data in a chemostat setting where a nitrification process was operated for over 500 days. The limitations and the insights of such an approach are discussed. In the second part, the use of an optimal tracking technique (developed within the framework of control theory) for the integration of data from genetic sequencing in chemostat models is presented. The optimal tracking revisits the data used in the aforementioned chemostat setting. The resulting model is an explanatory model, not a predictive one, it is able to reconstruct the different forms of nitrogen in the reactor by using the abundances of the operational taxonomic units, providing some insights into the growth rate of microbes in a complex community.

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

scholarly journals Characterisation of Lactobacillus rhamnosus VT1 and its effect on the growth of Candida maltosa YP1

2008 ◽  
Vol 25 (No. 5) ◽  
pp. 272-282 ◽  
Author(s):  
D. Liptáková ◽  
Ľ. Valík ◽  
A. Lauková ◽  
V. Strompfová
Keyword(s):  
Growth Rate ◽  
Incubation Temperature ◽  
Lactobacillus Rhamnosus ◽  
Microbial Interactions ◽  
Lag Phase ◽  
Regression Equations ◽  
Candida Maltosa ◽  
Food Protection ◽  
Spoilage Yeast ◽  
Standard Response

The combined effect of initial amount of 18 h <i>L. rhamnosus</i> VT1 inoculum and incubation temperature on the growth of <i>Candida maltosa</i> YP1, an oxidative food spoilage yeast strain, was primarily modelled and studied by standard response surface methodology. This study resulted in the following linear regression equations characterising lag time and growth rate of <i>C. maltosa</i> YP1 in milk in competition with the potentially protective lactobacillus strain. Lag-phase of <i>C. maltosa</i> was strongly influenced by the amount of lactobacillus inoculum (<i>V</i><sub>0</sub>) and incubation temperature (1/<i>T</i>). The synergic effect of both these factors was also evident as results from the equation lag = –33.50 + 186.38 × <i>V</i><sub>0</sub> × 1/<i>T</i> + 512.27 × 1/<i>T</i> – 5.511 × <i>V</i><sub>0</sub> (<i>R</i><sup>2</sup><sub>(λ)</sub> = 0.849). The growth rate was sufficiently described by the linear relation: <i>Gr</i><sub>Cm</sub> = –0.00046 + 0.0033 × <i>T</i> – 0.0016 × <i>V</i><sub>0 (<i>R</i><sup>2</sup><sub>(Gr)</sub> = 0.847). On the basis of these equations, the mutual microbial interactions and the potential application of the lactobacillus strains to food protection are discussed.

scholarly journals Phylogenetic Core Groups: a promising concept in search of a consistent methodological framework

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Alberto Pascual-García
Keyword(s):  
Microbial Communities ◽  
Microbial Ecology ◽  
Environmental Conditions ◽  
The Novel ◽  
Methodological Framework ◽  
Operational Taxonomic Units ◽  
Traditional Classification ◽  
Taxonomical Classification ◽  
Novel Concept

AbstractIn this comment, we analyse the conceptual framework proposed by Aguirre de Cárcer (Microbiome 7:142, 2019), introducing the novel concept of Phylogenetic Core Groups (PCGs). This notion aims to complement the traditional classification in operational taxonomic units (OTUs), widely used in microbial ecology, to provide a more intrinsic taxonomical classification which avoids the use of pre-determined thresholds. However, to introduce this concept, the author frames his proposal in a wider theoretical framework based on a conceptualization of selection that we argue is a tautology. This blurs the subsequent formulation of an assembly principle for microbial communities, favouring that some contradictory examples introduced to support the framework appear aligned in their conclusions. And more importantly, under this framework and its derived methodology, it is not possible to infer PCGs from data in a consistent way. We reanalyse the proposal to identify its logical and methodological flaws and, through the analysis of synthetic scenarios, we propose a number of methodological refinements to contribute towards the determination of PCGs in a consistent way. We hope our analysis will promote the exploration of PCGs as a potentially valuable tool, helping to bridge the gap between environmental conditions and community composition in microbial ecology.

Dispersion in fatigue crack growth rate and processing of experimental data

1984 ◽  
Vol 20 (3) ◽  
pp. 259-265
Author(s):  
S. Ya. Yarema ◽  
L. S. Mel'nichok ◽  
B. A. Popov
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Crack Growth Rate

Interpretation of Experimental Data with Regard to the Activated Sludge Model No.1 and Calibration of the Model for Municipal Wastewater Treatment Plants

1992 ◽  
Vol 25 (6) ◽  
pp. 167-183 ◽  
Author(s):  
H. Siegrist ◽  
M. Tschui
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Municipal Wastewater Treatment ◽  
Activated Sludge Model

The wastewater of the municipal treatment plants Zürich-Werdhölzli (350000 population equivalents), Zürich-Glatt (110000), and Wattwil (20000) have been characterized with regard to the activated sludge model Nr.1 of the IAWPRC task group. Zürich-Glatt and Wattwil are partly nitrifying treatment plants and Zürich-Werdhölzli is fully nitrifying. The mixing characteristics of the aeration tanks at Werdhölzli and Glatt were determined with sodium bromide as a tracer. The experimental data were used to calibrate hydrolysis, heterotrophic growth and nitrification. Problems arising by calibrating hydrolysis of the paniculate material and by measuring oxygen consumption of heterotrophic and nitrifying microorganisms are discussed. For hydrolysis the experimental data indicate first-order kinetics. For nitrification a maximum growth rate of 0.40±0.07 d−1, corresponding to an observed growth rate of 0.26±0.04 d−1 was calculated at 10°C. The half velocity constant found for 12 and 20°C was 2 mg NH4-N/l. The calibrated model was verified with experimental dam of me Zürich-Werdhölzli treatment plant during ammonia shock load.

scholarly journals Microbiome of the Rhizosphere: from Structure to Functions

2021 ◽  
Author(s):  
Ning Ling ◽  
Tingting Wang ◽  
Yakov Kuzyakov
Keyword(s):  
Nitrogen Fixation ◽  
Microbial Ecology ◽  
16S Rdna ◽  
N Cycling ◽  
Microbial Interactions ◽  
Community Diversity ◽  
Organic Substances ◽  
Microbial Composition ◽  
Soil Function ◽  
Copiotrophic Bacteria

Abstract Microbial composition and functioning in the rhizosphere are among the most fascinating but hidden topics in microbial ecology. We generalized bacterial traits regarding community diversity, composition and functions using published 16s rDNA amplicon sequences of 584 pairs of bulk soils vs rhizosphere of crops. The lower bacterial diversity in the rhizosphere (-7% richness) compared to root-free soil reflects the excess of available organic substances near the root. The rhizosphere is enriched by Bacteroidetes, Proteobacteria and Cyanobacteria as well as other copiotrophic bacteria (r strategists). Complex but unstable bacterial networks in rhizosphere reflect tight microbial interactions and adaptations to fluctuating conditions common for r strategists. The dominant dormancy strategy in the rhizosphere is the toxin-antitoxin system, while sporulation is common in bulk soil. Function prediction analysis showed that the rhizosphere is strongly enriched (50–115%) in methanol oxidation, ureolysis, cellulolysis, chitinolysis and nitrogen fixation, but strongly depleted in functions related to N-cycling.

scholarly journals Dynamic of the Accelerated Expansion of the Universe in the DGP Model

2011 ◽  
Vol 21 (3) ◽  
pp. 253 ◽  
Author(s):  
Vo Quoc Phong
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Cold Dark Matter ◽  
Growth Index ◽  
Cosmic Acceleration ◽  
Accelerated Expansion ◽  
Density Parameter ◽  
Type Ia ◽  
Age Of The Universe ◽  
The Universe

According to experimental data of SNe Ia (Supernovae type Ia), we will discuss in detial dynamics of the DGP model and introduce a simple parametrization of matter $\omega$, in order to analyze scenarios of the expanding universe and the evolution of the scale factor. We find that the dimensionless matter density parameter at the present epoch $\Omega^0_m=0.3$, the age of the universe $t_0= 12.48$ Gyr, $\frac{a}{a_0}=-2.4e^{\frac{-t}{25.56}}+2.45$. The next we study the linear growth of matter perturbations, and we assume a definition of the growth rate, $f \equiv \frac{dln\delta}{dlna}$. As many authors for many years, we have been using a good approximation to the growth rate $f \approx \Omega^{\gamma(z)}_m$, we also find that the best fit of the growth index, $\gamma(z)\approx 0.687 - \frac{40.67}{1 + e^{1.7. (4.48 + z)}}$, or $\gamma(z)= 0.667 + 0.033z$ when $z\ll1$. We also compare the age of the universe and the growth index with other models and experimental data. We can see that the DGP model describes the cosmic acceleration as well as other models that usually refers to dark energy and Cold Dark Matter (CDM).

scholarly journals The effect of sludge retention time (SRT) on the Nitrifier typical kinetics at ambient temperature under the low ammonia density

2021 ◽  
Author(s):  
Yifan Li ◽  
Jinzhu Wu ◽  
Yongjie Liu ◽  
Feiyong Chen ◽  
Jie Guan ◽  
...  
Keyword(s):  
Growth Rate ◽  
Ambient Temperature ◽  
Retention Time ◽  
Stable State ◽  
Species Structure ◽  
Maximum Reaction Rate ◽  
Sludge Retention Time ◽  
Structure Changes ◽  
Nitrification Process ◽  
D 20

Abstract Sludge retention time (SRT) regulation is one of the essential management techniques for refined control of the main-sidestream treatment process under the low ammonia density. It is indispensable to understand the effect of SRTs changes on the Nitrifier kinetics to obtain the functional separation of the Nitrifier and the refined control of the nitrification process. In this study, Nitrifier was cultured with conditions of 35 ± 0.5 °C, pH 7.5 ± 0.2, DO 5.0 ± 0.5 mg-O/L, and SRTs was controlled for 40 d, 20 d, 10 d, and 5 d. The net growth rate (), decay rate (), specific growth rate (), the yield of the Nitrifier (), temperature parameter (), and inhibition coefficient () have been measured and extended with the SRT decreases. Instead, the half-saturation coefficient () decreased. In addition, the limited value of pH inhibition occurs (), and the pH of keeping 5% maximum reaction rate () was in a relatively stable state. The trade of kinetics may be induced by the species structure of Nitrifier changed. The Nitrosomonas proportion was increased, and the Nitrospira used to be contrary with the SRT decreasing. It is a match for the functional separation of Nitrifier when SRTs was 20 d at ambient temperature under the low ammonia density. The kinetics of ammonia-oxidizing organism (AOO) and nitrite-oxidizing organism (NOO) in Nitrifier under different SRT conditions should be measured respectively to the refined control of the partial nitrification process in the future study. HIGHLIGHT The Nitrifier typical kinetics used to be affected notably by way of SRTs changes. The species structure of the Nitrifier was recognized beneath distinctive SRTs. The change of Nitrifier kinetics with SRTs used to be estimated by the species structure changes.

Microbial community composition is linked to Sphagnum acclimation to warming

2021 ◽  
Author(s):  
Tatjana Živković ◽  
Alyssa A Carell ◽  
Gustaf Granath ◽  
Mats B Nilsson ◽  
Manuel Helbig ◽  
...  
Keyword(s):  
Growth Rate ◽  
Host Plant ◽  
Climate Warming ◽  
Elevated Temperatures ◽  
Critical Role ◽  
Temperature Acclimation ◽  
Microbial Interactions ◽  
Germ Free ◽  
Wide Range ◽  
Thermal Origin

&lt;p&gt;Peatlands store about third of the terrestrial carbon (C) and exert long-term climate cooling. Dominant plant genera in acidic peatlands, &lt;em&gt;Sphagnum&lt;/em&gt; mosses, are main contributors to net primary productivity. Through associative relationships with diverse microbial organisms (microbiome), &lt;em&gt;Sphagnum&lt;/em&gt; mosses control major biogeochemical processes, namely uptake, storage and potential release of carbon and nitrogen. Climate warming is expected to negatively impact C accumulation in peatlands and alter nutrient cycling, however &lt;em&gt;Sphagnum&lt;/em&gt;-dominated peatland resilience to climate warming may depend on &lt;em&gt;Sphagnum&lt;/em&gt;-microbiome associations. The ability of the microbiome to rapidly acclimatize to warming may aid &lt;em&gt;Sphagnum&lt;/em&gt; exposed to elevated temperatures through host-microbiome acquired thermotolerance. We investigated the role of the microbiome on &lt;em&gt;Sphagnum&lt;/em&gt;&amp;#8217;s ability to acclimate to elevated temperatures using a microbiome-transfer approach to test: a) whether the thermal origin of the microbiome influences acclimation of &lt;em&gt;Sphagnum&lt;/em&gt; growth and b) if microbial benefits to &lt;em&gt;Sphagnum&lt;/em&gt; growth depend on donor &lt;em&gt;Sphagnum&lt;/em&gt; species.&lt;/p&gt;&lt;p&gt;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160; Using a full-factorial design, microbiomes were separated from &lt;em&gt;Sphagnum&lt;/em&gt; &amp;#8220;donor&amp;#8221; species from four different peatlands across a wide range of thermal environments (11.4-27&amp;#176;C). The microbiomes were transferred onto germ-free &amp;#8220;recipient&amp;#8221; &lt;em&gt;Sphagnum&lt;/em&gt; species in the laboratory and exposed to a range of experimental temperatures (8.5 &amp;#8211; 26.5&amp;#176;C) for growth analysis over 4 weeks.&lt;/p&gt;&lt;p&gt;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160; Normalized growth rates were maximized for plants that received a microbiome from a matched &amp;#8220;donor&amp;#8221; and with a similar origin temperature (&amp;#916;T&lt;sub&gt;treatment-origin&lt;/sub&gt;: 0.3&amp;#177;0.9&amp;#176;C [&amp;#177;standard error], p = 0.73). For non-matched &amp;#8220;donor-recipient&amp;#8221; &lt;em&gt;Sphagnum&lt;/em&gt; pairs, &amp;#916;T&lt;sub&gt;treatment-origin&lt;/sub&gt; was slightly negative with -4.1&amp;#177;2.1&amp;#176;C (p = 0.06). The largest growth rate of the &amp;#8220;recipient&amp;#8221; was measured when grown with a microbiome from a matching &amp;#8220;donor&amp;#8221; &lt;em&gt;Sphagnum&lt;/em&gt; species and was 252% and 48% larger than the maximum growth rate of the germ-free &lt;em&gt;Sphagnum&lt;/em&gt; and the non-matched &amp;#8220;donor-recipient&amp;#8221; &lt;em&gt;Sphagnum&lt;/em&gt; pairs, respectively.&lt;/p&gt;&lt;p&gt;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160; Our results suggest that the composition of the &lt;em&gt;Sphagnum&lt;/em&gt; microbiome plays a critical role in host plant temperature acclimation. We found that microbially-provided benefits to the host plant were most pronounced when: 1) the thermal origin of the microbiome is similar to experimental temperatures, and 2) when donor and recipient &lt;em&gt;Sphagnum&lt;/em&gt; species are the same. Together, these results suggest that &lt;em&gt;Sphagnum&lt;/em&gt; temperature acclimation can be modulated, in part, by microbial interactions and may potentially play a role in peatland resilience to climate warming.&lt;/p&gt;

Young’s Experiment on Slits with an Angle Between Them

2014 ◽  
Vol 9 (2) ◽  
pp. 173-179
Author(s):  
Anton Bogomyagkov ◽  
Viktor Dorokhov ◽  
Oleg Meshkov ◽  
Aleksandr Polygalov ◽  
Alexey Shcheglov
Keyword(s):  
Experimental Data ◽  
Interference Pattern ◽  
Intensity Distribution ◽  
Mathematical Analysis ◽  
Theoretical Calculations ◽  
Experimental Results ◽  
Digital Data ◽  
Hyperbolic Function ◽  
Standard Laboratory ◽  
Arbitrary Angle

Here are proposed a modified version of Young’s experiment on slits with an arbitrary angle between them. Also here performed mathematical analysis of the proposed scheme, showing that the intensity distribution can be approximated by a hyperbolic function. Experimental data confirm theoretical calculations. Analysis of the experimental results has conducted using two different methods of processing the digital data of the interference pattern. Theoretical calculations and experimental results established a nontrivial fact, that the interference patterns for slits with different, but symmetrical respect to 90° angles have the same intensity distribution. This experiment may be used as a standard laboratory work in University on optics workshop

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