Search results for "Darwin"
showing 10 items of 96 documents
Politica industriale ed evoluzione dei settori industriali: alcune implicazioni di evolutionary economics
2012
The debate on state aids to firms and in general the debate on the state role on industrial policy lasts fro a long time. It is endless, because lack not only rigorous empirical evidence of the measure effectiveness, but also a non-organic theory of the subject. A first theoretical discrimination between in-dustrial policies on structure and performance allow us to make some pre-liminary considerations and following implications of research. If the former aimed at changing the genotype, such as the policies that have fostered sus-tainable development based on creation and spread of knowledge, the latter are limited, on the other side, to phenotypic changes characterized by short-term and ma…
Senescence and longevity : from physiological mechanisms to evolutionary processes : studies in birds and mammals
2012
There is an incredible diversity of lifespan in the animal kingdom ranging from a few days for small gastrotrichs worms to several hundred of years for some bivalves or tortoises. This amazing diversity has long questioned biology researchers. The growing interest in the phenomenon of aging, mainly due to the increase in life expectancy in humans, has questioned researchers on processes that determine patterns of longevity and ageing. On the one hand, biomedical and biogerontological studies helped describe numerous cellular and physiological mechanisms related to aging. Among these mechanisms, oxidative stress has been identified as playing a major role, through life-time accumulation of d…
Reading a Qubit Quantum State with a Quantum Meter: Time Unfolding of Quantum Darwinism and Quantum Information Flux
2019
Quantum non-Markovianity and quantum Darwinism are two phenomena linked by a common theme: the flux of quantum information between a quantum system and the quantum environment it interacts with. In this work, making use of a quantum collision model, a formalism initiated by Sudarshan and his school, we will analyse the efficiency with which the information about a single qubit gained by a quantum harmonic oscillator, acting as a meter, is transferred to a bosonic environment. We will show how, in some regimes, such quantum information flux is inefficient, leading to the simultaneous emergence of non-Markovian and non-darwinistic behaviours.
Le théâtre, témoin d'humeur de la science.
2008
Pour la Science - Hors série Les Génies de la Science
Identification of the ectosymbiotic bacteria of Mixotricha paradoxa involved in movement symbiosis
2003
Mixotricha paradoxa, a trichomonad from the hindgut of the Australian termite Mastotermes darwiniensis Froggatt, is a rare example of a movement symbiosis between eukaryotic and prokaryotic microorganisms. The surface of Mixotricha paradoxa is covered with spirochaetes and a rod-shaped bacterium. The four flagella at the anterior end seem only to alter the direction of movement, while the ectosymbiotic spirochaetes propel the flagellate cells. Based on a 16S rDNA sequence analysis after a semi-specific PCR, and subsequent fluorescence in situ hybridization applying helper oligonucleotides and a denaturing step of the 16S rRNA, three different spirochaete clones could be clearly identified o…
Bacterial Ectosymbionts which Confer Motility: Mixotricha paradoxa from the Intestine of the Australian Termite Mastotermes darwiniensis
2005
Darwinism and the Origin of Life
2012
Abstract Historically, ideas on the origins of life have been mingled with evolutionary explanations. Darwin avoided discussing the origin of the very first species in public although he acknowledged the possibility that life originated by natural causes. Some of his followers adopted this materialistic position and advocated some sort of spontaneous generation in the distant past. Nevertheless, Pasteur’s experiments were a major obstacle for scientific acceptance of the sudden emergence of life. The scientific study of the origin of life, established in the 1920s, required abandoning the idea of a unique chance event and considering a view of life emerging as the result of a long evolution…
Charles Darwin and the Origin of Life
2009
When Charles Darwin published The Origin of Species 150 years ago he consciously avoided discussing the origin of life. However, analysis of some other texts written by Darwin, and of the correspondence he exchanged with friends and colleagues demonstrates that he took for granted the possibility of a natural emergence of the first life forms. As shown by notes from the pages he excised from his private notebooks, as early as 1837 Darwin was convinced that “the intimate relation of Life with laws of chemical combination, & the universality of latter render spontaneous generation not improbable”. Like many of his contemporaries, Darwin rejected the idea that putrefaction of preexisting organ…
Darwin et l'après-Darwin : une histoire de l'hypothèse de sélection dans la théorie de l'évolution
1992
Les historiens et les biologistes n'ont pas assez distingué la théorie et l'hypothèse de sélection naturelle. En tant que théorie générale de l'histoire de la vie, la doctrine de la sélection naturelle a sans aucun doute eu un immense retentissement dans la science et dans la culture de son temps. Mais l'hypothèse centrale de cette théorie, dans la forme très contraignante que lui avait donnée Darwin, s'est trouvée très vite exposée à des difficultés internes suffisamment redoutables pour entrer en crise à peine était-elle née. En liant rigidement l'hypothèse de sélection à l'hérédité, Darwin l'a exposée pour au moins cinquante ans à la menace permanente d'une réfutation. La sélection darwi…