Programmer un pays : Cybernétique et matérialisme dialectique en RDA

Définie comme science générale de la régulation et de la communication s’appliquant aussi bien aux machines, aux êtres vivants qu’à la société, la cybernétique a été profondément marquée aussi bien par son contexte de développement, la Deuxième Guerre mondiale, que par les milieux où elle fut appliquée, à l’époque de la guerre froide. À l’Est, si la cybernétique fut au départ considérée comme une science « bourgeoise », l’appareil d’État a dû se rendre à l’évidence, son utilisation était nécessaire dans bien des domaines, à commencer par celui des technologies militaires. De son côté, un philosophe influent, Georg Klaus (1912-1974), a su convaincre la direction du parti de la compatibilité de la cybernétique avec le marxisme-léninisme. Dès lors, sous cette double impulsion, les années 1960 ont été marquées par une véritable conversion du pays, la cybernétique devenant la science de la programmation, en informatique bien sûr, mais aussi pour la planification économique et dans bien d’autres domaines.Cybernetics, defined as the science of regulation and communication pertaining to machines, human beings or society, bears the traces of the context in which it was elaborated—Second World War—and of the different areas where it was put into practical use during the Cold War. If initially in the East cybernetics was considered a bourgeois science, the state apparatus soon realised its crucial importance in many fields of activity, and most prominently, in developing military technology. In parallel, the influential philosopher Georg Klaus (1912-1974) convinced the party leaders of the compatibility of cybernetics and Marxism-Leninism. From then on, driven by this double impetus, the 1960s were marked by a downright conversion of the country as cybernetics became the science of programming, within computing research of course, but also in economic planning and other fields

La société Max Planck de 1946 à la réunification allemande : entre continuité et ruptures

Max Planck Society From 1946 to German reunification: Continuity and ruptures The Max Planck Society represents the fleuron of German research. Founded at two different times, 1946 and 1948, this society “for the advancement of science” is the successor to the Kaiser-Wilhelm-Gesellschaft (KWG), which was created in 1911 and dismantled after World War II. Is there continuity or rupture between these two organizations? This question deserves attention. At the level of the scientific organization, a new principle was founded along side the « principles of Hamack » at the beginning of the Nazi era. This principle, “voluntary realignment” (Selbstgleichschaltung), was away of avoiding more direct and radical intervention by Nazi functionaries. Industry was still represented at the level of administration. For example, IG Farben general secretary Carl Bosch succeeded Max Planck as the head of the KWG from 1937 to 1940, before being replaced by a staunch Nazi, Albert Vögler. Coming out of the war, when Otto Hahn returned home from Farm Hall where he was kept under house arrest, the very survival of German research structures was at stake. British Colonel Bertie Blount found compromise was possible with his proposal to rename the KWG. In 1946, the British convinced the Americans to create the Max Planck Society (MPG) in their two zones of occupation. Three years later, the French agreed to permit the MPG in their zone. Under the direction of Butenandt, the 1960s were characterized by strong expansion as well as the introduction of the principle of collegial direction. The physician Reimar Lust (1972 to 1984) assured a certain continuity despite crisis and the MPG confirmed that it was firmly anchored in the West. On the other side of the Iron Curtain, in the Soviet zone of occupation, the KWI was integrated into the Academy of Sciences of the RDA. In 1990 the RFA supported affiliation with the East German organizations, but the prestigious MPG, which had achieved wealth and stature that was the envy of universities, cited respect for the principles of Harnack in its refusal to incorporate outright East German research centers. New institutes have been created, headed by foreigners or West Germans, to prepare the science of tomorrow while watching over the promotion of interdisciplinary research

Gödel : une révolution en mathématiques. Essai sur les conséquences scientifiques et philosophiques des théorèmes gödeliens

Les théorèmes proposés autour de 1930 par le mathématicien Kurt Gödel (1906-1978) ont un statut particulier en philosophie. Comme le rappelle André Delessert, les théorèmes d'incomplétude qui démontrent l'existence d'expressions formellement indémontrables sont souvent cités pour affirmer que les fondements des mathématiques ne sont pas aussi solides qu'on pourrait le croire. Nombreux sont les intellectuels qui ont cru voir là la justification de divers propos finissant par se perdre en génér..

Battle of wits: the complete story of codebreaking in World War II

La construction des radars puis celle de la bombe atomique constituent deux témoignages aujourd'hui bien documentés du rôle joué par les scientifiques lors de la Seconde Guerre mondiale. Le livre de Stephen Budiansky présente la cryptologie, qui réunit la cryptographie et la cryptoanalyse, comme un autre domaine permettant d'offrir aux scientifiques mais aussi à tous les employés des centres de cryptoanalyse la place qui leur revient dans l'histoire de la guerre. La bataille de l'Atlantique e..

Battle of wits: the complete story of codebreaking in World War II

La construction des radars puis celle de la bombe atomique constituent deux témoignages aujourd'hui bien documentés du rôle joué par les scientifiques lors de la Seconde Guerre mondiale. Le livre de Stephen Budiansky présente la cryptologie, qui réunit la cryptographie et la cryptoanalyse, comme un autre domaine permettant d'offrir aux scientifiques mais aussi à tous les employés des centres de cryptoanalyse la place qui leur revient dans l'histoire de la guerre. La bataille de l'Atlantique e..

Battle of wits: the complete story of codebreaking in World War II

La construction des radars puis celle de la bombe atomique constituent deux témoignages aujourd'hui bien documentés du rôle joué par les scientifiques lors de la Seconde Guerre mondiale. Le livre de Stephen Budiansky présente la cryptologie, qui réunit la cryptographie et la cryptoanalyse, comme un autre domaine permettant d'offrir aux scientifiques mais aussi à tous les employés des centres de cryptoanalyse la place qui leur revient dans l'histoire de la guerre. La bataille de l'Atlantique e..

Les premiers « replieurs » français : Michel Goldberg à l’Institut Pasteur et Jeannine Yon à Orsay

The First French « Protein Folders »: Michel Goldberg at the Pasteur Institute and Jeannine Yon at Orsay Proteins, the building blocks of life, have since the 1930s been the object of studies to gain a better understanding of the formation of their three-dimensional structure. This structure, called conformation, determines the function of the protein. At the beginning of the 1960s, Anfinsen’s hypothesis stipulated that the protein’s conformation in a natural state in which the protein is functioning, corresponds to the state in which free energy was at its lowest. A thermodynamic principle therefore explained the protein folding. At the same time, at the Institut Pasteur, Jacques Monod and his colleagues were interested in the phenomena of regulation that takes place in the cell. The allosteric model, which was developed by this group, had a huge influence on the work of two French researchers, Michel Goldberg and Jeannine Yon. Yon was a specialist in enzymes and had studied the changes in conformation that accompany the formation of the enzyme-base complex. Goldberg was a young Polytechnician who had converted to biology. Having chosen the Institut Pasteur as the site of his research, Goldberg was at the heart of the discussions that marked the beginning of molecular biology in France. The work of these two researchers permitted new debate on Anfinsen’s hypothesis by showing that the control of the « repliement » was not only thermodynamic but was, equally, kinetic : one should from this point study the folding speed and the intermediary stages. The protein folding still constitutes important research today. These two researchers participated in the birth of the proteomics, the emerging discipline that permits making use of the knowledge of sequencing in different genomes and, also allows better understand of certain diseases caused by folding anomalies, such as Alzheimer and Creutzfeldt-Jakob diseases

A Selective Interplay between Aberrant EPSPKA and INaP Reduces Spike Timing Precision in Dentate Granule Cells of Epileptic Rats

Spike timing precision is a fundamental aspect of neuronal information processing in the brain. Here we examined the temporal precision of input–output operation of dentate granule cells (DGCs) in an animal model of temporal lobe epilepsy (TLE). In TLE, mossy fibers sprout and establish recurrent synapses on DGCs that generate aberrant slow kainate receptor–mediated excitatory postsynaptic potentials (EPSPKA) not observed in controls. We report that, in contrast to time-locked spikes generated by EPSPAMPA in control DGCs, aberrant EPSPKA are associated with long-lasting plateaus and jittered spikes during single-spike mode firing. This is mediated by a selective voltage-dependent amplification of EPSPKA through persistent sodium current (INaP) activation. In control DGCs, a current injection of a waveform mimicking the slow shape of EPSPKA activates INaP and generates jittered spikes. Conversely in epileptic rats, blockade of EPSPKA or INaP restores the temporal precision of EPSP–spike coupling. Importantly, EPSPKA not only decrease spike timing precision at recurrent mossy fiber synapses but also at perforant path synapses during synaptic integration through INaP activation. We conclude that a selective interplay between aberrant EPSPKA and INaP severely alters the temporal precision of EPSP–spike coupling in DGCs of chronic epileptic rats