Maximal Growth when Food Output Is Uncertain

1971 ◽  
pp. 157-166
Author(s):  
Avinash K. Dixit
Keyword(s):  
Maximal Growth

Resonant generation of electromagnetic surface wave by inhomogeneous relativistic electron stream

1981 ◽  
Vol 26 (3) ◽  
pp. 509-515 ◽  
Author(s):  
V. M. Čadež ◽  
S. Vuković ◽  
V. V. Frolov ◽  
A. Yu. Kyrie
Keyword(s):  
Surface Wave ◽  
Growth Rates ◽  
Doppler Effect ◽  
Maximal Growth ◽  
Electron Stream ◽  
Particle Flows ◽  
Anomalous Doppler Effect ◽  
Excitation Mechanisms ◽  
Resonant Generation ◽  
Cerenkov Effect

Generation of electromagnetic surface waves by relativistic inhomogeneous particle flows is investigated for plane and cylindrical geometries. The basic excitation mechanisms are shown to be the induced anomalous Doppler effect and the hydrodynamic Čerenkov effect. The relevant maximal growth rates may differ significantly from those derived for monoenergetic beams.

scholarly journals Stability Analysis of the Labrador Current

2014 ◽  
Vol 44 (2) ◽  
pp. 445-463 ◽  
Author(s):  
Sören Thomsen ◽  
Carsten Eden ◽  
Lars Czeschel
Keyword(s):  
Stability Analysis ◽  
Growth Rates ◽  
Baroclinic Instability ◽  
Cross Flow ◽  
Vertical Shear ◽  
Maximal Growth ◽  
Phase Velocities ◽  
Labrador Current ◽  
Lateral Mixing ◽  
Weak Stratification

Abstract Mooring observations and model simulations point to an instability of the Labrador Current (LC) during winter, with enhanced eddy kinetic energy (EKE) at periods between 2 and 5 days and much less EKE during other seasons. Linear stability analysis using vertical shear and stratification from the model reveals three dominant modes of instability in the LC: 1) a balanced interior mode with along-flow wavelengths of about 30–45 km, phase velocities of 0.3 m s−1, maximal growth rates of 1 day−1, and surface-intensified but deep-reaching amplitudes; 2) a balanced shallow mode with along-flow wavelengths of about 0.3–1.5 km, phase velocities of 0.55 m s−1, about 3 times larger growth rates, but amplitudes confined to the mixed layer (ML); and 3) an unbalanced symmetric mode with the largest growth rates, vanishing phase speeds, and along-flow structure, and very small cross-flow wavelengths, also confined to the ML. Both balanced modes are akin to baroclinic instability but operate at moderate-to-small Richardson numbers Ri with much larger growth rates as for the quasigeostrophic limit of Ri ≫ 1. The interior mode is found to be responsible for the instability of the LC during winter. Weak stratification and enhanced vertical shear due to local buoyancy loss and the advection of convective water masses from the interior result in small Ri within the LC and up to 3 times larger growth rates of the interior mode in March compared to summer and fall conditions. Both the shallow and the symmetric modes are not resolved by the model, but it is suggested that they might also play an important role for the instability in the LC and for lateral mixing.

Mesophilic mutants of an obligate psychrophile, Micrococcus cryophilus

1969 ◽  
Vol 15 (10) ◽  
pp. 1145-1150 ◽  
Author(s):  
P-C. Tai ◽  
H. Jackson
Keyword(s):  
Growth Temperature ◽  
Metabolic Pathways ◽  
Thermal Denaturation ◽  
Deoxyribonucleic Acid ◽  
Elevated Temperatures ◽  
Maximum Growth ◽  
Maximal Growth ◽  
Denaturation Temperature ◽  
Maximum Growth Temperature ◽  
Thermal Denaturation Temperature

Several mutants with elevated maximal growth temperature (MGT) were developed from an obligate psychrophile, Micrococcus cryophilus ATCC 15174, by ultraviolet irradiation. Two of the mutants, T8 and M19, have the most similar characteristics to those of their parent. The mutants lost the ability to grow well at 0 °C and showed changes in metabolic pathways while acquiring the ability to grow at elevated temperatures. Heat resistance and deoxyribonucleic acid thermal denaturation temperature were shown to be unrelated to maximum growth temperature. The significance of the mutants is discussed.

scholarly journals Proteotoxicity from aberrant ribosome biogenesis compromises cell fitness

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Blake W Tye ◽  
Nicoletta Commins ◽  
Lillia V Ryazanova ◽  
Martin Wühr ◽  
Michael Springer ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
Ribosome Assembly ◽  
Maximal Growth ◽  
Proliferating Cells ◽  
Cellular Processes ◽  
Direct Contribution ◽  
The Face ◽  
Cellular Phenotypes

To achieve maximal growth, cells must manage a massive economy of ribosomal proteins (r-proteins) and RNAs (rRNAs) to produce thousands of ribosomes every minute. Although ribosomes are essential in all cells, natural disruptions to ribosome biogenesis lead to heterogeneous phenotypes. Here, we model these perturbations in Saccharomyces cerevisiae and show that challenges to ribosome biogenesis result in acute loss of proteostasis. Imbalances in the synthesis of r-proteins and rRNAs lead to the rapid aggregation of newly synthesized orphan r-proteins and compromise essential cellular processes, which cells alleviate by activating proteostasis genes. Exogenously bolstering the proteostasis network increases cellular fitness in the face of challenges to ribosome assembly, demonstrating the direct contribution of orphan r-proteins to cellular phenotypes. We propose that ribosome assembly is a key vulnerability of proteostasis maintenance in proliferating cells that may be compromised by diverse genetic, environmental, and xenobiotic perturbations that generate orphan r-proteins.

scholarly journals Effect of Organic Solvents on the Yield of Solvent-Tolerant Pseudomonas putida S12

1999 ◽  
Vol 65 (6) ◽  
pp. 2631-2635 ◽  
Author(s):  
Sonja Isken ◽  
Antoine Derks ◽  
Petra F. G. Wolffs ◽  
Jan A. M. de Bont
Keyword(s):  
Growth Rate ◽  
Pseudomonas Putida ◽  
Organic Solvents ◽  
Critical Concentration ◽  
Bacterial Membrane ◽  
Maximal Growth ◽  
Wild Type ◽  
Active Efflux ◽  
Maximal Growth Rate ◽  
Solvent Tolerant

ABSTRACT Solvent-tolerant microorganisms are useful in biotransformations with whole cells in two-phase solvent-water systems. The results presented here describe the effects that organic solvents have on the growth of these organisms. The maximal growth rate of Pseudomonas putida S12, 0.8 h−1, was not affected by toluene in batch cultures, but in chemostat cultures the solvent decreased the maximal growth rate by nearly 50%. Toluene, ethylbenzene, propylbenzene, xylene, hexane, and cyclohexane reduced the biomass yield, and this effect depended on the concentration of the solvent in the bacterial membrane and not on its chemical structure. The dose response to solvents in terms of yield was linear up to an approximately 200 mM concentration of solvent in the bacterial membrane, both in the wild type and in a mutant lacking an active efflux system for toluene. Above this critical concentration the yield of the wild type remained constant at 0.2 g of protein/g of glucose with increasing concentrations of toluene. The reduction of the yield in the presence of solvents is due to a maintenance higher by a factor of three or four as well as to a decrease of the maximum growth yield by 33%. Therefore, energy-consuming adaptation processes as well as the uncoupling effect of the solvents reduce the yield of the tolerant cells.

Methodology for Enteropathogenic Escherichia coli

1975 ◽  
Vol 58 (2) ◽  
pp. 283-292
Author(s):  
Ira J Mehlman ◽  
Nicholas T Simon ◽  
Arvey C Sanders ◽  
Morris Fishbein ◽  
Joseph C Olson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Elevated Temperature ◽  
Growth Temperature ◽  
Maximal Growth ◽  
Enteropathogenic Escherichia Coli ◽  
Pathogenic Potential ◽  
Gram Negative ◽  
Tentative Identification ◽  
E Coli ◽  
Capsular Antigens

Abstract Pathogenic biotypes of Escherichia coli grow poorly at temperatures greatly different from that of the host. Percentages quantitatively recovered at 42.0, 44.0, 44.5, and 45.5°C in lauryl tryptose broth were 100, 76, 76, and 42, respectively. Corresponding values for 175 strains of varied origin were 98, 89, 82, and 65%. Maximal growth temperature is dependent upon medium. Lauryl tryptose and elevated coliform broths were equivalent in the recovery of small inocula (100 cells/ml) at 41.5–44.5°. Mac-Conkey, enteric enrichment, and Gram-negative broths were inhibitory at corresponding values. Growth at elevated temperature in nutrient broth is enhanced by carbohydrate. Standard lactose enrichment media fail to recover slow lactose fermenters. An acidified glutamic acid medium was unsuitable for recovery of E. coli. The data suggest modification of standard temperatures for the recovery of pathogenic biotypes. Previously recommended analytical methods have been simplified and supplemented. The enhancement of motility in indole-nitrite broth at 35°C is recommended. A 4-tube semiquantitative test is offered for tentative identification of somatic and capsular antigens. Inclusion of Alkalescens-Dispar strains is warranted by their pathogenic behavior. Examination in Shigella and Alkalescens-Dispar sera is required to cover the dysentery-like biotypes. Pathogenic potential cannot be inferred from serotype.

scholarly journals Extremal behavior in sectional matrices

2019 ◽  
Vol 18 (03) ◽  
pp. 1950041 ◽  
Author(s):  
Anna Bigatti ◽  
Elisa Palezzato ◽  
Michele Torielli
Keyword(s):  
Hilbert Functions ◽  
Maximal Growth ◽  
Homogeneous Ideal ◽  
Extremal Behavior ◽  
Hyperplane Sections ◽  
The Ideal

In this paper, we recall the object sectional matrix which encodes the Hilbert functions of successive hyperplane sections of a homogeneous ideal. We translate and/or reprove recent results in this language. Moreover, some new results are shown about their maximal growth, in particular, a new generalization of Gotzmann’s Persistence Theorem, the presence of a GCD for a truncation of the ideal, and applications to saturated ideals.

scholarly journals Modelling Methionine Requirements of Fast- and Slow-Growing Chinese Yellow-Feathered Chickens during the Starter Phase

Animals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 443 ◽  
Author(s):  
Long Li ◽  
K.F.M. Abouelezz ◽  
Zhonggang Cheng ◽  
A.E.G. Gad-Elkareem ◽  
Qiuli Fan ◽  
...  
Keyword(s):  
Regression Models ◽  
Polynomial Regression ◽  
Conversion Ratio ◽  
Quadratic Polynomial ◽  
Maximal Growth ◽  
Feed Conversion ◽  
Asymptotic Models ◽  
Males And Females ◽  
Slow Growing ◽  
Daily Gain

Two experiments were carried out to investigate the dietary methionine requirement for fast and slow-growing Chinese yellow-feathered breeds during the starter phase, based on growth variables and regression models. In Experiment 1, a total of 2880 one-day-old Lingnan chicks (fast growing breed) were used to test the methionine requirement from 1 to 21 days of age for males and females separately. Of each gender, 1440 birds were allocated into 6 dietary methionine levels (0.28%, 0.32%, 0.37%, 0.43%, 0.50% and 0.63%), each with 6 pen replicates of 40 chicks. Experiment 2 had the same design with Guangxi chicks (slow growing breed) from 1 to 30 d of age. Results indicated that significant nonlinear or quadratic responses to increasing dietary methionine levels were observed in body weight, daily gain, feed intake and feed conversion ratio of both breeds. In summary, the quadratic polynomial regression showed that the optimal methionine requirements for maximal growth performance of Lingnan chickens were 0.52–0.58% in males, 0.51% in females, and 0.53% in mixed genders. The corresponding values for Guangxi breed were 0.53% in males by quadratic polynomial regression and 0.43% in females, and 0.48% to 0.49% in mixed sexes by exponential asymptotic models.

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