ON MURATA DENSITIES

2011 ◽  
Vol 07 (07) ◽  
pp. 1717-1736
Author(s):  
CHRISTIAN BALLOT ◽  
MIREILLE CAR
Keyword(s):  
Growth Conditions ◽  
Density Functions ◽  
Abstract Theory ◽  
Global Function ◽  
Japan Acad ◽  
Arithmetical Semigroup ◽  
Set Up ◽  
Arithmetical Semigroups ◽  
Asymptotic Densities ◽  
Similar Classification

In this paper, we set up an abstract theory of Murata densities, well tailored to general arithmetical semigroups. In [On certain densities of sets of primes, Proc. Japan Acad. Ser. A Math. Sci.56(7) (1980) 351–353; On some fundamental relations among certain asymptotic densities, Math. Rep. Toyama Univ.4(2) (1981) 47–61], Murata classified certain prime density functions in the case of the arithmetical semigroup of natural numbers. Here, it is shown that the same density functions will obey a very similar classification in any arithmetical semigroup whose sequence of norms satisfies certain general growth conditions. In particular, this classification holds for the set of monic polynomials in one indeterminate over a finite field, or for the set of ideals of the ring of S-integers of a global function field (S finite).

scholarly journals Treatment with surfactants enables quantification of translational activity by O-propargyl-puromycin labelling in yeast

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jennifer Staudacher ◽  
Corinna Rebnegger ◽  
Brigitte Gasser
Keyword(s):  
Mammalian Cells ◽  
Growth Conditions ◽  
Non Invasive ◽  
Translational Activity ◽  
Wide Range ◽  
Simple Protocol ◽  
Set Up ◽  
Different Strains ◽  
Negative Controls ◽  
Global Translation

Abstract Background Translation is an important point of regulation in protein synthesis. However, there is a limited number of methods available to measure global translation activity in yeast. Recently, O-propargyl-puromycin (OPP) labelling has been established for mammalian cells, but unmodified yeasts are unsusceptible to puromycin. Results We could increase susceptibility by using a Komagataella phaffii strain with an impaired ergosterol pathway (erg6Δ), but translation measurements are restricted to this strain background, which displayed growth deficits. Using surfactants, specifically Imipramine, instead, proved to be more advantageous and circumvents previous restrictions. Imipramine-supplemented OPP-labelling with subsequent flow cytometry analysis, enabled us to distinguish actively translating cells from negative controls, and to clearly quantify differences in translation activities in different strains and growth conditions. Specifically, we investigated K. phaffii at different growth rates, verified that methanol feeding alters translation activity, and analysed global translation in strains with genetically modified stress response pathways. Conclusions We set up a simple protocol to measure global translation activity in yeast on a single cell basis. The use of surfactants poses a practical and non-invasive alternative to the commonly used ergosterol pathway impaired strains and thus impacts a wide range of applications where increased drug and dye uptake is needed.

Application of Sulfate-Reducing and Sulfide-Oxidizing Bacterial Symbiosis for Wastewater Treatment

1995 ◽  
Vol 30 (2) ◽  
pp. 305-324 ◽  
Author(s):  
V. Tare ◽  
P.C. Sabumon
Keyword(s):  
Organic Matter ◽  
Microbial Population ◽  
Domestic Wastewater ◽  
Growth Conditions ◽  
Sulfate Reducing ◽  
Bacterial Symbiosis ◽  
Scale Models ◽  
Microbial System ◽  
Set Up ◽  
Reducing Bacteria

Abstract This investigation attempted to advance the state of the art of the process which utilizes the symbiotic relationship between the sulfate-reducing bacteria (SRB) and sulfide oxidizing bacteria (SOB) for degradation of organic matter present in wastewater. Major emphasis has been on the development of the desired microbial system without any external seed and comparative evaluation of the two types of multistage reversing flow bioreactor (MRB) systems. Biological vessels (BVs) in the MRB systems simulate conditions which correspond to configurations described as upflow sludge blanket and stationary fixed film. Two bench-scale models – one designed to achieve self granulation of sludge (SGS), and the second designed to promote growth of SRB/SOB on additional nonreactive surface – were set up and operated over a period of 4 months. Domestic wastewater supplemented with organic matter from sugar cane molasses was used as feed to develop the desired microbial population. Several visual and microscopic observations confirmed the presence of a significant number of SRB and SOB in all the biological vessels. Results indicated that it is possible to develop SGS and a microbial population of SRB and SOB which could attach to the nonreactive surface without any external seeding. Domestic wastewater could serve as a source of these organisms. Immobilized growth conditions and suspended growth conditions in BVs yield similar results in terms of organic matter utilization. The empirical formula for MRB biomass can be expressed as C11O12H36N5S.

scholarly journals Abstract semilinear stochastic Itó-Volterra integrodifferential equations

2006 ◽  
Vol 2006 ◽  
pp. 1-22 ◽  
Author(s):  
David N. Keck ◽  
Mark A. McKibben
Keyword(s):  
Existence And Uniqueness ◽  
Separable Hilbert Space ◽  
Analogous Result ◽  
Growth Conditions ◽  
Integrodifferential Equations ◽  
Time Dependent ◽  
Abstract Theory ◽  
Approximation Result ◽  
Global Existence And Uniqueness ◽  
Real Separable Hilbert Space

We consider a class of abstract semilinear stochastic Volterra integrodifferential equations in a real separable Hilbert space. The global existence and uniqueness of a mild solution, as well as a perturbation result, are established under the so-called Caratheodory growth conditions on the nonlinearities. An approximation result is then established, followed by an analogous result concerning a so-called McKean-Vlasov integrodifferential equation, and then a brief commentary on the extension of the main results to the time-dependent case. The paper ends with a discussion of some concrete examples to illustrate the abstract theory.

Studies of the Nutritional, Environmental Effects and Repressive Nature of Simple Sugars on the Production of endo-β-mannanase by Aspergillus flavus PT7 on Solid State Fermentation

2019 ◽  
pp. 1-12
Author(s):  
Ukponobong E. Anita ◽  
Nsikak U. Stephen ◽  
Abiodun A. Onilude ◽  
Inimfon A. Ibanga
Keyword(s):  
Enzyme Activity ◽  
Environmental Factors ◽  
Aspergillus Flavus ◽  
Nitrogen Sources ◽  
Growth Conditions ◽  
Inoculum Size ◽  
Lag Period ◽  
Production Increase ◽  
Set Up ◽  
Ibadan Nigeria

Aims: The importance of nutritional and environmental factors in the production of microbial enzymes cannot be overemphasized. Hence, endo-β-mannanase production was systematically studied in a step-wise approach of building up on the experimentally observed conditions favouring the production of this enzyme in Aspergillus flavus PT7. Place and Duration of Study: Department of Microbiology, University of Ibadan, Nigeria, between January 2018 and December 2018. Methodology: Thirty-eight (38) fungal isolates obtained were screened for mannolytic ability using standard method. The highest producer of endo-β-mannasase was subjected to various production conditions by adjusting the nutritional and environmental factors in view of optimizing the production of this enzyme in the isolate Aspergillus flavus PT7. Results: Copra meal was the highest inducer of mannanase production in the isolate at enzyme activity of 85.86±3.93 U/gds. Production increased to 94.54±0.42 when all forms of extraneous nitrogen sources were excluded from the production medium. pH 5.0, temperature 30°C, moisture content at 100% v/w and inoculum size of 8.0% v/w led to the increase in production by 44% (enzyme activity of 153.24±5.69 U/gds) in 5 days of incubation. Allowing the production set up additional two (2) days led to production increase with a recorded enzyme activity of 170.34±4.35 U/gds. Production of endo-β-mannanase in A. flavus PT7 was observed to be inductive as the presence of simple sugars like glucose, galactose, arabinose and xylose led to extended lag period in the production of the enzymes by the isolate. Conclusion: Production of endo-β-mannanase by Aspergillus flavus PT7 was successfully optimized in a step-wise and systematic experimental study of the nutritional and environmental growth conditions of the isolate.

The function field abstract prime number theorem

1989 ◽  
Vol 106 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Stephen D. Cohen
Keyword(s):  
Finite Field ◽  
Prime Number ◽  
Function Field ◽  
Prime Number Theorem ◽  
Arithmetical Semigroup ◽  
Enumeration Problems ◽  
Ring Of Polynomials ◽  
Arithmetical Semigroups ◽  
Positive Integers ◽  
Free Commutative Semigroup

For arithmetical semigroups modelled on the positive integers, there is an ‘abstract prime number theorem’ (see, for example, [1]). In order to study enumeration problems in the several arithmetical categories whose prototype instead is the ring of polynomials in an indeterminate over a finite field of order q, Knopfmacher[2, 3] introduced the following modification. An additive arithmetical semigroup G is a free commutative semigroup with an identity, generated by a countable set of ‘primes’ P and admitting an integer-valued degree mapping ∂ with the properties(i) ∂(l) = 0,∂(p) > 0 for p∈P;(ii) ∂(ab) = ∂(a) + ∂(b) for all a, b in G;(iii) the number of elements in G of degree n is finite. (This number will be denoted by G(n).)

scholarly journals The art of growing plants for experimental purposes: a practical guide for the plant biologist

2012 ◽  
Vol 39 (11) ◽  
pp. 821 ◽  
Author(s):  
Hendrik Poorter ◽  
Fabio Fiorani ◽  
Mark Stitt ◽  
Uli Schurr ◽  
Alex Finck ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Growth Conditions ◽  
Plant Performance ◽  
Experimental Conditions ◽  
Rooting Medium ◽  
Critical Issues ◽  
Light Quantity ◽  
Controlled Environments ◽  
Plant Biologist ◽  
Set Up

Every year thousands of experiments are conducted using plants grown under more-or-less controlled environmental conditions. The aim of many such experiments is to compare the phenotype of different species or genotypes in a specific environment, or to study plant performance under a range of suboptimal conditions. Our paper aims to bring together the minimum knowledge necessary for a plant biologist to set up such experiments and apply the environmental conditions that are appropriate to answer the questions of interest. We first focus on the basic choices that have to be made with regard to the experimental setup (e.g. where are the plants grown; what rooting medium; what pot size). Second, we present practical considerations concerning the number of plants that have to be analysed considering the variability in plant material and the required precision. Third, we discuss eight of the most important environmental factors for plant growth (light quantity, light quality, CO2, nutrients, air humidity, water, temperature and salinity); what critical issues should be taken into account to ensure proper growth conditions in controlled environments and which specific aspects need attention if plants are challenged with a certain a-biotic stress factor. Finally, we propose a simple checklist that could be used for tracking and reporting experimental conditions.

The Effects of Drying Techniques on Clay-Rich Soil Texture

1974 ◽  
Vol 32 ◽  
pp. 466-467
Author(s):  
T. G. Naymik
Keyword(s):  
Critical Point ◽  
Liquid Nitrogen ◽  
Liquid Nitrogen Temperature ◽  
Drying Methods ◽  
Air Drying ◽  
Freeze Dried ◽  
Critical Point Drying ◽  
Set Up ◽  
The Relationship ◽  
Quartz Grains

Three techniques were incorporated for drying clay-rich specimens: air-drying, freeze-drying and critical point drying. In air-drying, the specimens were set out for several days to dry or were placed in an oven (80°F) for several hours. The freeze-dried specimens were frozen by immersion in liquid nitrogen or in isopentane at near liquid nitrogen temperature and then were immediately placed in the freeze-dry vacuum chamber. The critical point specimens were molded in agar immediately after sampling. When the agar had set up the dehydration series, water-alcohol-amyl acetate-CO2 was carried out. The objectives were to compare the fabric plasmas (clays and precipitates), fabricskeletons (quartz grains) and the relationship between them for each drying technique. The three drying methods are not only applicable to the study of treated soils, but can be incorporated into all SEM clay soil studies.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

Eels Under Standing Wave Conditions

1982 ◽  
Vol 40 ◽  
pp. 492-495
Author(s):  
O.L. Krivanek ◽  
J. TaftØ
Keyword(s):  
Standing Wave ◽  
Wave Conditions ◽  
Set Up ◽  
A Site ◽  
Complex Crystal

It is well known that a standing electron wavefield can be set up in a crystal such that its intensity peaks at the atomic sites or between the sites or in the case of more complex crystal, at one or another type of a site. The effect is usually referred to as channelling but this term is not entirely appropriate; by analogy with the more established particle channelling, electrons would have to be described as channelling either through the channels or through the channel walls, depending on the diffraction conditions.

Low-Loss Images in a Stem/Tem Microscope

1976 ◽  
Vol 34 ◽  
pp. 496-497 ◽  
Author(s):  
David C. Joy ◽  
Dennis M. Maher
Keyword(s):  
High Resolution ◽  
Surface Topography ◽  
Beam Direction ◽  
Low Loss ◽  
Specimen Holder ◽  
Glancing Angle ◽  
High Resolution Images ◽  
Set Up ◽  
Conventional Manner ◽  
Objective Type

High-resolution images of the surface topography of solid specimens can be obtained using the low-loss technique of Wells. If the specimen is placed inside a lens of the condenser/objective type, then it has been shown that the lens itself can be used to collect and filter the low-loss electrons. Since the probeforming lenses in TEM instruments fitted with scanning attachments are of this type, low-loss imaging should be possible.High-resolution, low-loss images have been obtained in a JEOL JEM 100B fitted with a scanning attachment and a thermal, fieldemission gun. No modifications were made to the instrument, but a wedge-shaped, specimen holder was made to fit the side-entry, goniometer stage. Thus the specimen is oriented initially at a glancing angle of about 30° to the beam direction. The instrument is set up in the conventional manner for STEM operation with all the lenses, including the projector, excited.

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