Studies in the Alismataceae. V. Experimental modification of phyllotaxis in pseudostolons of Echinodorus tenellus by means of growth inhibitors

1974 ◽  
Vol 52 (5) ◽  
pp. 1131-1142 ◽  
Author(s):  
W. A. Charlton
Keyword(s):  
Stable State ◽  
Main Axis ◽  
Trimethylammonium Chloride ◽  
Succinamic Acid ◽  
Lateral Buds ◽  
Experimental Findings ◽  
High Degree ◽  
Vegetative Bud ◽  
Experimental Modification

Treatment with triiodobenzoic acid (TIBA), N-dimethylamino succinamic acid (B-995), and (2-chloroethyl)trimethylammonium chloride (CCC) can modify the pattern of development of the pseudostolons of Echinodorus tenellus. In particular, CCC and B-995 can with a high degree of success suppress the normal reversal of genetic spiral of the pseudostolon. Other aspects of phyllotaxis, including phyllotaxis of lateral buds, are not affected by CCC and B-995.The pseudostolons, as previously described, are modified inflorescences bearing bracts in false whorls of three, and a vegetative bud in the axil of the first bract of each set after the first. After passing through a brief stabilizing phase the pseudostolon enters a stable state in which the direction of genetic spiral of the main axis reverses with the initiation of the second bract of each set, and in which the genetic spiral of the lateral vegetative bud is quite consistently homodromous with that of the main axis at the time of initiation of the bud.The experimental findings are discussed in relation to the earlier descriptive and analytical studies of E. tenellus. Some previously erected hypotheses relating to control of phyllotaxis in this plant are invalidated. It is suggested that in E. tenellus determination of maintenance or reversal of genetic spiral occurs within a short span of development between the initiation of the first and second bract of each set, and that direction of genetic spiral in the pseudostolon and its vegetative laterals may be controlled by mechanisms independent of those controlling other aspects of phyllotaxis such as divergence angle.

Feasibility of Molecular Structure Determination With a High Resolution Electron Microscope

1968 ◽  
Vol 26 ◽  
pp. 338-339
Author(s):  
T. A. Welton
Keyword(s):  
Electron Microscope ◽  
Substrate Surface ◽  
Helical Axis ◽  
Base Plane ◽  
Resolution Electron ◽  
High Resolution Electron Microscope ◽  
High Degree ◽  
Degree Of Order ◽  
Purine Pyrimidine

An ultimate design goal for an improved electron microscope, aimed at biological applications, is the determination of the structure of complex bio-molecules. As a prototype of this class of problems, we propose to examine the possibility of reading DNA sequence by an imaginable instrument design. This problem ideally combines absolute importance and relative simplicity, in as much as the problem of enzyme structure seems to be a much more difficult one.The proposed technique involves the deposition on a thin graphite lamina of intact double helical DNA rods. If the structure can be maintained under vacuum conditions, we can then make use of the high degree of order to greatly reduce the work involved in discriminating between the four possible purine-pyrimidine arrangements in each base plane. The phosphorus atoms of the back bone form in projection (the helical axis being necessarily parallel to the substrate surface) two intertwined sinusoids. If these phosphorus atoms have been located up to a certain point on the molecule, we have available excellent information on the orientation of the base plane at that point, and can then locate in projection the key atoms for discrimination of the four alternatives.

scholarly journals Influence of the Share of Renewable Energy Sources on the Level of Energy Security in EECCA Countries

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 903 ◽  
Author(s):  
Ivan Trifonov ◽  
Dmitry Trukhan ◽  
Yury Koshlich ◽  
Valeriy Prasolov ◽  
Beata Ślusarczyk
Keyword(s):  
Renewable Energy ◽  
Energy Security ◽  
Structural Characteristics ◽  
Renewable Energy Sources ◽  
Energy Resource ◽  
Energy Sources ◽  
Structural Content ◽  
High Degree

In this study we aimed to determine the extent to which changes in the share of renewable energy sources, their structural complex, and the level of energy security in Eastern Europe, Caucasus and Central Asia (EECCA) countries in the medium- and long-term are interconnected. The study was performed through modeling and determination of the structural characteristics of energy security in the countries. The methodology of the approach to modeling was based on solving the problem of nonlinear optimization by selecting a certain scenario. For the study, the data of EECCA countries were used. The ability of EECCA countries to benefit from long-term indirect and induced advantages of the transformation period depends on the extent to which their domestic supply chains facilitate the deployment of energy transformation and induced economic activity. This study provides an opportunity to assess the degree of influence of renewable energy sources on the level of energy security of countries in the context of energy resource diversification. The high degree of influence of renewable energy sources on energy security in the EECCA countries has been proven in the implementation of the developed scenarios for its increase. Energy security is growing. At the same time, its level depends not only on an increase in the share of renewable sources but also on the structure of energy resources complex of countries, and the development of various renewable energy sources. Therefore, today the EECCA countries are forced not only to increase the share of renewable energy sources but also to attach strategic importance to the structural content of their energy complex.

Resistance to Outflow of Cerebrospinal Fluid Determined by Bolus Injection Technique and Constant Rate Steady State Infusion in Humans

Neurosurgery ◽  
1985 ◽  
Vol 16 (3) ◽  
pp. 336-340 ◽  
Author(s):  
Michael Kosteljanetz
Keyword(s):  
Cerebrospinal Fluid ◽  
Steady State ◽  
Bolus Injection ◽  
Point Of View ◽  
Injection Technique ◽  
Communicating Hydrocephalus ◽  
Constant Rate ◽  
High Degree ◽  
Infusion Technique

Abstract Two methods for the determination of resistance to the outflow of cerebrospinal fluid, the bolus injection technique and the constant rate steady state infusion technique, were compared. Thirty-two patients with a variety of intracranial diseases (usually communicating hydrocephalus) were studied. There was a high degree of correlation between the resistance values obtained with the two methods, but values based on the bolus injection technique were systematically and statistically significantly lower than those obtained with the constant rate infusion test. From a practical point of view. both methods were found to be applicable in a clinical setting.

scholarly journals Magnetic and Electronic Properties of Weyl Semimetal Co2MnGa Thin Films

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 251
Author(s):  
Peter Swekis ◽  
Aleksandr S. Sukhanov ◽  
Yi-Cheng Chen ◽  
Andrei Gloskovskii ◽  
Gerhard H. Fecher ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Electronic Properties ◽  
Photoelectron Spectroscopy ◽  
Magnetic Moments ◽  
Field Orientation ◽  
Weyl Semimetal ◽  
Uniform Magnetization ◽  
Experimental Findings ◽  
High Degree

Magnetic Weyl semimetals are newly discovered quantum materials with the potential for use in spintronic applications. Of particular interest is the cubic Heusler compound Co2MnGa due to its inherent magnetic and topological properties. This work presents the structural, magnetic and electronic properties of magnetron co-sputtered Co2MnGa thin films, with thicknesses ranging from 10 to 80 nm. Polarized neutron reflectometry confirmed a uniform magnetization through the films. Hard x-ray photoelectron spectroscopy revealed a high degree of spin polarization and localized (itinerant) character of the Mn d (Co d) valence electrons and accompanying magnetic moments. Further, broadband and field orientation-dependent ferromagnetic resonance measurements indicated a relation between the thickness-dependent structural and magnetic properties. The increase of the tensile strain-induced tetragonal distortion in the thinner films was reflected in an increase of the cubic anisotropy term and a decrease of the perpendicular uniaxial term. The lattice distortion led to a reduction of the Gilbert damping parameter and the thickness-dependent film quality affected the inhomogeneous linewidth broadening. These experimental findings will enrich the understanding of the electronic and magnetic properties of magnetic Weyl semimetal thin films.

scholarly journals Large elastic deformations of isotropic materials. I. Fundamental concepts

1948 ◽  
Vol 240 (822) ◽  
pp. 459-490 ◽  
Keyword(s):  
The Body ◽  
Elastic Behaviour ◽  
Stress And Strain ◽  
Elastic Deformations ◽  
Hooke’S Law ◽  
Widespread Agreement ◽  
Wide Range ◽  
Hooke's Law ◽  
High Degree

The mathematical theory of small elastic deformations has been developed to a high degree of sophistication on certain fundamental assumptions regarding the stress-strain relationships which are obeyed by the materials considered. The relationships taken are, in effect, a generalization of Hooke’s law— ut tensio, sic vis . The justification for these assumptions lies in the widespread agreement of experiment with the predictions of the theory and in the interpretation of the elastic behaviour of the materials in terms of their known structure. The same factors have contributed to our appreciation of the limitations of these assumptions. The principal problems, which the theory seeks to solve, are the determination of the deformation which a body undergoes and the distribution of stresses in it, when certain forces are applied to it, and when certain points of the body are subjected to specified displacements. These problems are always dealt with on the assumption that the generalization of Hooke’s law is obeyed by the material of the body and that the deformation is small, i.e. the change of length, in any linear element in the material, is small compared with the length of the element in the undeformed state. Apart from the fact that the generalization of Hooke’s law is obeyed accurately by a very wide range of materials, under a considerable variety of stress and strain conditions, it has the further advantage that it leads to a mathematically tractable theory.

EVALUATION OF PROTEIN IN FOODS: IV. A SIMPLIFIED CHEMICAL SCORE

1959 ◽  
Vol 37 (1) ◽  
pp. 1293-1299 ◽  
Author(s):  
J. M. McLaughlan ◽  
C. G. Rogers ◽  
D. G. Chapman ◽  
J. A. Campbell
Keyword(s):  
Rapid Screening ◽  
Assay Method ◽  
Efficiency Ratio ◽  
Lysine Concentration ◽  
Chemical Score ◽  
Group A ◽  
High Degree ◽  
The Relationship ◽  
Bio Assay

Available evidence has shown that most common foods are deficient in lysine, methionine, or in methionine and cystine. Based on the determination of these amino acids, a simplified chemical score was developed and compared with protein efficiency ratio (P.E.R.) values determined with the same samples. Each of 43 foods was assigned to either of two categories: (a) foods apparently deficient in lysine or (b) in methionine (+ cystine). With 16 foods in the former group there was a high degree of correlation between lysine concentration and P.E.R. With 27 foods in the latter group, a good correlation was found between the methionine (+ cystine) concentration and P.E.R. Since the regression lines for the two groups were different, a factor was added to the methionine (+ cystine) values to simplify the relationship. That foods deficient in lysine or in methionine (+ cystine) fell into two distinct groups appeared to be substantiated by data available in the literature. Because the simplified method is relatively rapid, yields reproducible results, and correlates with animal assays, it is proposed as a rapid screening procedure for the evaluation of protein in foods, but is not intended to replace the rat bio-assay method.

Determination of Sample Size in Service Inspection

1997 ◽  
Vol 119 (1) ◽  
pp. 57-60
Author(s):  
S. Qin ◽  
G. E. O. Widera
Keyword(s):  
Sample Size ◽  
Large Volume ◽  
Analysis Method ◽  
Degree Of Confidence ◽  
Impossible Task ◽  
The Mean ◽  
High Degree ◽  
Service Inspection ◽  
False Rejection

When performing inservice inspection on a large volume of identical components, it becomes an almost impossible task to inspect all those in which defects may exist, even if their failure probabilities are known. As a result, an appropriate sample size needs to be determined when setting up an inspection program. In this paper, a probabilistic analysis method is employed to solve this problem. It is assumed that the characteristic data of components has a certain distribution which can be taken as known when the mean and standard deviations of serviceable and defective sets of components are estimated. The sample size can then be determined within an acceptable assigned error range. In this way, both false rejection and acceptance can be avoided with a high degree of confidence.

scholarly journals Amplitude response of a telemetered seismic system from seismometers to digital acquisition system

1995 ◽  
Vol 38 (1) ◽  
Author(s):  
R. Di Giovambattista ◽  
S. Barba ◽  
A. Marchetti
Keyword(s):  
Digital Signals ◽  
Amplitude Response ◽  
Automatic Mode ◽  
Steady State Method ◽  
Sinusoidal Current ◽  
Fully Automatic ◽  
The Difference ◽  
High Degree ◽  
Seismic System

Automated amplitude response of the complete seismometer, telemetry and recording system js obtaiued trom sinusoidal inputs to the calibration coil. Custom-built software was designed to perform fully automatic cali- bration analyses of the digital signals. In this paper we describe the signals used for calibration and interactive and batch procedures designed to obtain calibration functions in automatic mode. By using a steady-state method we reach a high degree of accuracy in the determination of both the frequency and amplitude of the \ignal. The only parameters required by this procedure are the seismometer mass, the calibration-coil constant and the intensity of the current injected into the calibration coil. This procedure is applicable to telemetered seismic systems and represents an optimization of the processing time. The software was designed to requjre no modification" jf the device used to generate the sinusoidal current should change. In particular, it is possi- ble to changc the number of monotrequcncy packages transmitted to the calibration coil with the on]y restric- tion that the difference between the frequency of two consecutjve packages be greater than 5%; for these rea- sons the procedure is expected to be usefu] for the seismological community. The paper inc]udes a generaI de- scription of thc designing criteria, and of the hardware and software architecture, as well as an account of thc system's performancc during a two year period of operation.

scholarly journals The use of parallel computing for the high-resolution determination of earthquake source parameters

2019 ◽  
pp. 68-75
Author(s):  
A. S. Fomochkina ◽  
V. G. Bukchin
Keyword(s):  
Parallel Computing ◽  
Focal Mechanism ◽  
Source Parameters ◽  
Nodal Plane ◽  
Earthquake Parameters ◽  
Earthquake Source Parameters ◽  
Detailed Search ◽  
High Degree ◽  
Special Case

Alongside the determination of the focal mechanism and source depth of an earthquake by direct examination of their probable values on a grid in the parameter space, also the resolution of these determinations can be estimated. However, this approach requires considerable time in the case of a detailed search. A special case of a shallow earthquake whose one nodal plane is subhorizontal is an example of the sources that require the use of a detailed grid. For studying these events based on the records of the long-period surface waves, the grids with high degree of detail in the angles of the focal mechanism are required. We discuss the application of the methods of parallel computing for speeding up the calculations of earthquake parameters and present the results of studying the strongest aftershock of the Tohoku, Japan, earthquake by this approach.

scholarly journals Determination of thermodynamic stability of FeB monoboride

2019 ◽  
Vol 27 (2) ◽  
pp. 69-76
Author(s):  
N. Yu. Filonenko ◽  
A. N. Galdina
Keyword(s):  
Thermodynamic Stability ◽  
Boron Content ◽  
Boron Concentration ◽  
Cast Alloy ◽  
Thermodynamic Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Temperature Expansion ◽  
Experimental Findings

In this paper we investigate the phase composition and phase transformations in the Fe-B system alloys with boron content in the range of 9.0–15.0 wt.%. We use microstructural, X-ray diffraction, differential thermal and durometric analyzes to determine the physical properties of the alloys. The experimental findings show that in the as-cast alloy structure there is Fe5B3 phase in small quantities along with FeB monoboride and Fe2B boride. The Fe5B3 phase is formed as a result of the peritectic reaction L+FeB→Fe5B3 at the temperature of 1680 K. The eutectic transformation L→Fe5B3 +Fe2B occurs in the boron concentration range of 8.8–10.5 wt.%. After annealing of the Fe-B alloys at the temperature of 1473 K and cooling with the rate of 102 K/s we observe the occurring of the Fe5B3 phase. To spot an opportunity of the secondary monoboride formation in the alloys under consideration, we calculate the thermodynamic characteristics of stability of the system. Accounting for the contribution of the first degree approximation of high-temperature expansion of thermodynamic potential of FeB iron monoboride in a Fe-B binary alloy enables us to study its thermodynamic stability. It is shown that stability decrease of FeB at 1423 K allows suggesting that at this temperature the phase transformation occurs and this fact correlates to the differential thermal analysis results.

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