scholarly journals The evolution of replicators

2000 ◽  
Vol 355 (1403) ◽  
pp. 1669-1676 ◽  
Author(s):  
Eörs Szathmáry
Keyword(s):  
Harmful Effect ◽  
Lipid Vesicles ◽  
System Size ◽  
Point Of View ◽  
Side Reactions ◽  
Evolutionary Potential ◽  
Satisfactory Solution ◽  
Small System ◽  
Human Culture ◽  
Successive Addition

Replicators of interest in chemistry, biology and culture are briefly surveyed from a conceptual point of view. Systems with limited heredity have only a limited evolutionary potential because the number of available types is too low. Chemical cycles, such as the formose reaction, are holistic replicators since replication is not based on the successive addition of modules. Replicator networks consisting of catalytic molecules (such as reflexively autocatalytic sets of proteins, or reproducing lipid vesicles) are hypothetical ensemble replicators, and their functioning rests on attractors of their dynamics. Ensemble replicators suffer from the paradox of specificity: while their abstract feasibility seems to require a high number of molecular types, the harmful effect of side reactions calls for a small system size. No satisfactory solution to this problem is known. Phenotypic replicators do not pass on their genotypes, only some aspects of the phenotype are transmitted. Phenotypic replicators with limited heredity include genetic membranes, prions and simple memetic systems. Memes in human culture are unlimited hereditary, phenotypic replicators, based on language. The typical path of evolution goes from limited to unlimited heredity, and from attractor–based to modular (digital) replicators.

Linear and nonlinear behaviour of two-stream instabilities in collisionless plasmas

2015 ◽  
Vol 81 (6) ◽  
Author(s):  
Y. W. Hou ◽  
M. X. Chen ◽  
M. Y. Yu ◽  
B. Wu
Keyword(s):  
Normal Mode Analysis ◽  
System Size ◽  
Point Of View ◽  
Mode Analysis ◽  
Nonlinear Behaviour ◽  
Initial Growth ◽  
Small Magnitude ◽  
Plasma Oscillations ◽  
Numerical Noise ◽  
Growth Properties

The transient, growth and nonlinear saturation stages in the evolution of the electrostatic two-stream instabilities as described by the Vlasov–Poisson system are reconsidered by numerically following the evolution of the total wave energy of the plasma oscillations excited from (numerical) noise. Except for peculiarities related to the necessarily finite (even though very small) magnitude of the perturbations in the numerical simulation, the existence and initial growth properties of the instabilities from the numerical results are found to be consistent with those from linear normal mode analysis and the Penrose criteria. However, contradictory to the traditional point of view, the growth of instability before saturation is not always linear. The initial stage of the growth can exhibit fine structures that can be attributed to the harmonics of the excited plasma oscillations, whose wavelengths are determined by the system size and the numerical noise. As expected, saturation of the unstable oscillations is due to electron trapping when they reach sufficiently large amplitudes.

Two Methods of Protection against Oxygen and the Improvement Which Results from Their Combined Use. I. Observations on the Mechanism of Protection

1947 ◽  
Vol 20 (4) ◽  
pp. 949-961 ◽  
Author(s):  
Jean Le Bras
Keyword(s):  
Physical Properties ◽  
Single Case ◽  
Protective Action ◽  
Harmful Effect ◽  
Point Of View ◽  
Theoretical Conclusion ◽  
Free Oxygen ◽  
Practical Point ◽  
Combined Use ◽  
Rate Of Absorption

Abstract The observations which are recorded in the present paper represent an extension of the single case of litharge which has already been described. They show that, when small percentages of certain substances are added to rubber with a view to protecting the rubber from deterioration by oxygen, these substances are capable of directing the combination of oxygen with the rubber in different ways. This is shown by the fact that, as a result, a given percentage of combined oxygen does not lead to the same deterioration in physical properties. This difference in behavior can be explained logically on the basis of the antioxygenic theory by assuming that some agents act, not by retarding the rate of oxidation, but by deactivating the peroxides as soon as they are formed. By what term are these agents to be designated? First of all it should be recalled how an antioxygenic substance is defined. Every substance is an antioxygenic agent when it has the power, in small percentages, of retarding the rate of absorption of free oxygen by an autoxidizable substance. This definition obviously does not apply to a perfect deactivating agent, since the latter has no effect on the rate of absorption of oxygen, in spite of it too protecting rubber against deterioration by oxygen, and therefore being equally worthy, from the practical point of view, of being called an antioxygenic agent. However, this would only lead to confusion between the phenomenon itself and its effects. Furthermore, since commercial antioxygenic substances appear to show, to a greater or less degree, a combination of the two actions, one might consider designating them by some term which would embody both mechanisms. The word “antiaging agent” is not suitable, for it is too general and applies to cases where, in addition to oxygen, other influences such as light and repeated flexing play a part. There is, then, a problem in terminology to be settled, but this will have to be left unanswered provisionally until sufficient facts which have a more direct bearing on the case are available. Finally attention should be called to the useful effect which may be pictured as a possibility when the two types of protective agents which have been described act jointly. In other words, if the two mechanisms in question were to be superimposed, it would appear to be possible to improve considerably the resistance of rubber to deterioration by oxygen, since any oxygen which escapes the protective action of the true antioxygenic agent has its harmful effect reduced by the deactivating agent. To express it figuratively, it might be said that oxygen which has succeeded in overcoming the first obstacle opposing its action finds itself confronted with a new defense which puts the oxygen partially out of action. As shown by experiments carried out on this subject, which are described in the following paper of this series, this theoretical conclusion is actually borne out by the results of the experiments.

scholarly journals The homogeneous catalysis of gaseous reactions by iodine. The decomposition of propionic aldehyde, and a general discussion

1933 ◽  
Vol 142 (846) ◽  
pp. 77-88 ◽  
Keyword(s):  
Kinetic Analysis ◽  
Homogeneous Catalysis ◽  
Chemical Change ◽  
Point Of View ◽  
The Other ◽  
Side Reactions ◽  
General Point ◽  
Chemical Changes ◽  
Secondary Reactions ◽  
The One

Previous papers have dealt with the homogeneous catalysis of the decomposition of ethers and of acetaldehyde by iodine. The problem of the mechanism of these catalysed reactions can be approached in two ways: on the one hand, by seeking to obtain as complete a picture as possible of the types of chemical change which are susceptible to the action of a given catalyst, and, the catalysts which will promote a given chemical change; and, on the other hand, by investigating in detail the kinetics and molecular statistics of individual reactions. Experiments on the different kinds of reaction which iodine will catalyse are being published elsewhere. Most of the chemical changes have involved too many side reactions, or secondary reactions with the catalyst, to be suitable for complete kinetic analysis. Nevertheless, they show the chemical specificity of the action of iodine in the clearest manner, and this aspect of the problem is discussed from a general point of view in the last section of the present paper.

scholarly journals Place of Literature in the System of Philosophical Hermeneutics

2015 ◽  
pp. 4-8
Author(s):  
Oksana A. Koval ◽  
Ekaterina B. Krukova
Keyword(s):  
Theoretical Model ◽  
Literary Text ◽  
Point Of View ◽  
Modern Literature ◽  
Philosophical Hermeneutics ◽  
Historical School ◽  
Human Culture ◽  
Leading Role ◽  
The World

The authors attempt to build a theoretical model of the understanding of literature from the perspective of philosophical hermeneutics where the language takes a leading role in the process of formation of human culture. From this point of view, the literature receives a specific status of an existential practice in our being-in-the-world. The strategy of perception and interpretation of a literary text, offered by H-G. Gadamer, strongly contrasts with the traditional way of interpretation practiced by the historical school of hermeneutics, but, for this reason, it seems to be the most adequate to the processes happening in the modern literature.

scholarly journals On-site solar powered refueling stations for green hydrogen production and distribution: performances and costs

2022 ◽  
Vol 334 ◽  
pp. 01005
Author(s):  
Simona Di Micco ◽  
Mariagiovanna Minutillo ◽  
Alessandra Perna ◽  
Elio Jannelli
Keyword(s):  
Hydrogen Production ◽  
Economic Analysis ◽  
Essential Element ◽  
Energy Transition ◽  
Economic Indicator ◽  
System Size ◽  
Point Of View ◽  
Environmental Benefits ◽  
Innovative Technology ◽  
Battery System

Today, the hydrogen is considered an essential element in speeding up the energy transition and generate important environmental benefits. Not all hydrogen is the same, though. The “green hydrogen”, which is produced using renewable energy and electrolysis to split water, is really and completely sustainable for stationary and mobile applications. This paper is focused on the techno-economic analysis of an on-site hydrogen refueling station (HRS) in which the green hydrogen production is assured by a PV plant that supplies electricity to an alkaline electrolyzer. The hydrogen is stored in low pressure tanks (200 bar) and then is compressed at 900 bar for refueling FCHVs by using the innovative technology of the ionic compressor. From technical point of view, the components of the HRS have been sized for assuring a maximum capacity of 450 kg/day. In particular, the PV plant (installed in the south of Italy) has a size of 8MWp and supplies an alkaline electrolyzer of 2.1 MW. A Li-ion battery system (size 3.5 MWh) is used to store the electricity surplus and the grid-connection of the PV plant allows to export the electricity excess that cannot be stored in the battery system. The economic analysis has been performed by estimating the levelized cost of hydrogen (LCOH) that is an important economic indicator based on the evaluation of investment, operational & maintenance and replacement costs. Results highlighted that the proposed on-site configuration in which the green hydrogen production is assured, is characterized by a LCOH of 10.71 €/kg.

Suggestions and Debates

1974 ◽  
Vol 7 (1) ◽  
pp. 31-57
Author(s):  
William J. Mcgrath
Keyword(s):  
Social Psychology ◽  
Point Of View ◽  
Human Culture

While on vacation in Rome during the fall of 1913, Freud mentioned in a letter that his visit to the eternal city had restored his zest for work and that in addition to several other pieces he had written the preface to his book Totem and Taboo. In this preface he modestly notes that essays “represent a first attempt on my part at applying the point of view and the findings of psycho-analysis to some unsolved problems of social psychology,” but taken as a whole the four essays in fact present as bold and ingenious a theory on the nature and origins of human civilization as that proposed in Rousseau's Second Discourse a century and a half earlier. Rome was, in every sense, an appropriate place to launch such an ambitious undertaking, and as a connoisseur of jokes and irony Freud may well have chosen his vacation residence, the Eden Hotel, at least in part because of its name. However, the picture Freud draws of primitive man's first steps toward the establishment of civilization is far from edenic. Near the end of Totem and Taboo Freud conjures up a description of the primal crime on which human culture rests: “One day the brothers who had been driven out came together; killed and devoured their father and so made an end of the patriarchal horde. United, they had the courage to do and succeeded in doing what would have been impossible for them individually.”

The Hellenic Crisis from the Point of View of Constitutional and International Law Part III

1918 ◽  
Vol 12 (2) ◽  
pp. 312-337
Author(s):  
Theodore P. Ion
Keyword(s):  
International Law ◽  
Point Of View ◽  
Satisfactory Solution ◽  
The Third ◽  
Public Property ◽  
Law Of Nations ◽  
Greek Government ◽  
The Government ◽  
The Military ◽  
Of Greece

The third part of the essay on the Hellenic Crisis, which has happily received a satisfactory solution, will deal with the incidents which are connected with the law of nations and inquire as to how far the European belligerents in their dealings with Greece, and the Greek Government in its relations with them, adhered to the tenets and usages of international law.The points to be here discussed are of a manifold character.First, it will be examined whether the serious charge made by the Entente Powers against Constantine, the ex-King of the Hellenes, that he violated the obligations arising out of the Treaty of Alliance between Greece and Serbia, by which the two states bound themselves to assist each other for the defense of their respective territories in case of attack by a third Power, and particularly by Bulgaria, is well founded according to the letter and spirit of the instrument of alliance.Secondly, whether the military occupation of portions of the territory of the Hellenic Kingdom by both sets of belligerents, the seizure of its war material and other public property, and particularly the coercive measures employed by the Entente Powers against the Government and people of Greece and their forcible intervention in the internal affairs of that country, can be justified either by reason of treaty stipulations or on account of the unneutral conduct of the then King and his government towards the Entente Allies. The first point to be examined is the obligation arising out of the treaty of alliance between Greece and Serbia.

Limits of the Jurisdiction of the Permanent Court of International Justice

1931 ◽  
Vol 25 (2) ◽  
pp. 203-213 ◽  
Author(s):  
Frank B. Kellogg
Keyword(s):  
Point Of View ◽  
International Justice ◽  
Legal Rights ◽  
Satisfactory Solution ◽  
The Future ◽  
The Moment

While I agree with the action taken by the Court and consider that, in view of the unsatisfactory and contradictory provisions of the special agreement by which the parties have submitted this case to the Court, it is perhaps the only course by which the Court could, under its Statute, aid the parties in arriving at a wholly satisfactory solution of their dispute, nevertheless, in view of certain language used in the order, which might be the source of doubt as to the limits of the jurisdiction of this Court and might serve as a basis of argument that it is within the competence of this Court, with the consent of the parties, to take jurisdiction of and decide purely political questions upon considerations of expediency without regard to the legal rights of the parties, I feel it incumbent upon me to make the following observations:In my opinion the question of the competence of this Court which has been raised by the present case and a direct decision of which the Court has avoided, for the moment at least, by the making of the present order, is, from the point of view of the future of this Court and the development of the judicial settlement of international disputes, by far the most important question which has ever been brought before the Permanent Court of International Justice. I feel, therefore, that I would be derelict in my duty if I allowed the question to be passed over in silence or left any doubt as to my opinion in regard thereto.

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