327,809 research outputs found
A Computational Model of Symbiotic Composition in Evolutionary Transitions
No full textSeveral of the major transitions in evolutionary history, such as the symbiogenic origin of eukaryotes from prokaryotes, share the feature that existing entities became the components of composite entities at a higher level of organisation. This composition of pre-adapted extant entities into a new whole is a fundamentally different source of variation from the gradual accumulation of small random variations, and it has some interesting consequences for issues of evolvability. Intuitively, the pre-adaptation of sets of features in reproductively independent specialists suggests a form of ‘divide and conquer’ decomposition of the adaptive domain. Moreover, the compositions resulting from one level may become the components for compositions at the next level, thus scaling-up the variation mechanism. In this paper, we explore and develop these concepts using a simple abstract model of symbiotic composition to examine its impact on evolvability. To exemplify the adaptive capacity of the composition model, we employ a scale-invariant fitness landscape exhibiting significant ruggedness at all scales. Whilst innovation by mutation and by conventional evolutionary algorithms becomes increasingly more difficult as evolution continues in this landscape, innovation by composition is not impeded as it discovers and assembles component entities through successive hierarchical levels
Ybl Miklós és a Pollack család
No full textYbl Miklós (1814–1891) még a 19. század első felében született építészeknek ahhoz a generációjához tartozott, akiknek az egyre bomló, de még fennálló céhes rendszerben és céhes hagyományok közepette kellett megszerezniük a tervezés és építés jogát. Pályája alakulásában így nagy szerep jutott Pollack Mihálynak (1773–1855), akinél inaséveit töltötte az 1830-as évek első felében, majd a magyar földön is tevékenykedő, bécsi Heinrich Kochnak (1781–1861). A fiatal Ybl, amíg nem vált a céh teljes jogú tagjává, az édesapja nyomán szintén építész, és mesterjoggal rendelkező Pollack Ágostonnal (1810–1872) társulva próbálkozott meg saját praxisának kiépítésével. A néhány évig tartó társulás legjelentősebb épülete az ikervári Batthyány-kastély. Ekkor kezdődött Ybl munkakapcsolata a Károlyi családdal. A fóti megbízások, majd azok nyomán az uradalmi építészi státusz biztosította a fiatal építész megélhetését, valamint az arisztokráciával való kapcsolatépítés lehetőségét. A Pollack Ágostonnal való társas viszonya legkésőbb 1850 körül megszűnt. Pollack Mihály fiának tevékenységében a kis és közepes léptékű tervezési és építési feladatokról egyre inkább csak a kivitelezésre került át a hangsúly, majd Pollack Ágoston az 1860-as évek közepén teljesen felhagyott az építészettel. Ybl Miklós és a Pollack család kapcsolata azonban nem szakadt meg, a neoreneszánsz legnagyobb hazai mestere tervezte Pollack Mihály sírját, és árván maradt unokáját is örökbe fogadta.
|
Miklós Ybl (1814–1891) belonged to those generations of early 19th century born architects whom had to gain the right of designing and constructing in the midst of still existing, but declining guilds and their traditions. In the forming of Ybl’s career his master, Mihály Pollack (1773–1855) and the Viennese Heinrich Koch (1781–1861) had a definite rule. Until he became full member of the guild, the young Ybl collaborated with Ágoston Pollack (1812–1872), Mihály’s son, who had the warrant from the guild, and tried to establish a practice. The most significant building of the almost decade-long partnership is the Batthyány-mansion in Ikervár. This is the time also when Ybl’s relationship to the Károlyi family started. Their orders in Fót, and on account of those, the gained position of manorial architect provided wealthy subsistence and also the opportunity of being known in the circles of aristocracy. The partnership with the younger Pollack ended at latest around 1850. The son of Mihály Pollack slowly turned from designing small and mid-sized houses to constructions and in the middle of the 1860’s he laid off architecture for good. However, the connection between Miklós Ybl and the Pollack family have not ended, he designed Mihály’s grave, and adopted his orphaned grandchild
Cognitive behaviouralism in women's prisons: a critical analysis of therapeutic assumptions and practices
No full textDetlef Pollack und Gergely Rosta: Religion in der Moderne
No full textDetlef Pollack / Gergely Rosta (2015): Religion in der Moderne. Ein internationaler Vergleich, Frankfurt/M. / New York: Campus. 542 S., ISBN 978-3-593-50175-8, EUR 39,90
Embodied Evolution: Distributing an evolutionary algorithm in a population of robots
No full textWe introduce Embodied Evolution (EE) as a new methodology for evolutionary robotics (ER). EE uses a population of physical robots that autonomously reproduce with one another while situated in their task environment. This constitutes a fully distributed evolutionary algorithm embodied in physical robots. Several issues identified by researchers in the evolutionary robotics community as problematic for the development of ER are alleviated by the use of a large number of robots being evaluated in parallel. Particularly, EE avoids the pitfalls of the simulate-and-transfer method and allows the speed-up of evaluation time by utilizing parallelism. The more novel features of EE are that the evolutionary algorithm is entirely decentralized, which makes it inherently scalable to large numbers of robots, and that it uses many robots in a shared task environment, which makes it an interesting platform for future work in collective robotics and Artificial Life. We have built a population of eight robots and successfully implemented the first example of Embodied Evolution by designing a fully decentralized, asynchronous evolutionary algorithm. Controllers evolved by EE outperform a hand-designed controller in a simple application. We introduce our approach and its motivations, detail our implementation and initial results, and discuss the advantages and limitations of EE
Mutualism, Parasitism, and Evolutionary Adaptation
No full textOur investigations concern the role of symbiosis as an enabling mechanism in evolutionary adaptation. Previous work has illustrated how the formation of mutualist groups can guide genetic variation so as to enable the evolution of ultimately independent organisms that would otherwise be unobtainable. The new experiments reported here show that this effect applies not just in genetically related organisms but may also occur from symbiosis between distinct species. In addition, a new detail is revealed: when the symbiotic group members are drawn from two separate species only one of these species achieves eventual independence and the other remains parasitic. It is nonetheless the case that this second species, formerly mutualistic, was critical in enabling the independence of the first. We offer a biological example that is suggestive of the effect and discuss the implications for evolving complex organisms, natural and artificial
sj-docx-1-jdr-10.1177_00220345221100773 – Supplemental material for New Ameloblastoma Cell Lines Enable Preclinical Study of Targeted Therapies
No full textSupplemental material, sj-docx-1-jdr-10.1177_00220345221100773 for New Ameloblastoma Cell Lines Enable Preclinical Study of Targeted Therapies by J. Nguyen, P.S. Saffari, A.S. Pollack, S. Vennam, X. Gong, R.B. West and J.R. Pollack in Journal of Dental Research</p
Coevolutionary Dynamics in a Minimal Substrate
No full textOne of the central difficulties of coevolutionary methods arises from 'intransitive superiority' - in a two-player game, for example, the fact that A beats B, and B beats C, does not exclude the possibility that C beats A. Such cyclic superiority in a coevolutionary substrate is hypothesized to cause cycles in the dynamics of the population such that it 'chases its own tail' - traveling through some part of strategy space more than once despite apparent improvement with each step. It is often difficult to know whether an application domain contains such difficulties and to verify this hypothesis in the failure of a given coevolutionary set-up. In this paper we wish to elucidate some of the issues and concepts in an abstract domain where the dynamics of coevolution can be studied simply and directly. We define three simple 'number games' that illustrate intransitive superiority and resultant oscillatory dynamics, as well as some other relevant concepts. These include the distinction between a player's perceived performance and performance with respect to an external metric, and the significance of strategies with a multi-dimensional nature. These features alone can also cause oscillatory behavior and coevolutionary failure
Symbiotic Composition and Evolvability
No full textSeveral of the Major Transitions in natural evolution, such as the symbiogenic origin of eukaryotes from prokaryotes, share the feature that existing entities became the components of composite entities at a higher level of organisation. This composition of pre-adapted extant entities into a new whole is a fundamentally different source of variation from the gradual accumulation of small random variations, and it has some interesting consequences for issues of evolvability. In this paper we present a very abstract model of 'symbiotic composition' to explore its possible impact on evolvability. A particular adaptive landscape is used to exemplify a class where symbiotic composition has an adaptive advantage with respect to evolution under mutation and sexual recombination. Whilst innovation using conventional evolutionary algorithms becomes increasingly more difficult as evolution continues in this problem, innovation via symbiotic composition continues through successive hierarchical levels unimpeded. <br/
Recommended from our members
Biohazards in biological research: proceedings
No full textThe 1973 publication "Biohazards in Biological Research," edited by S. Hellman, M. Oxman, and R. Pollack, focuses on the risks and safety concerns associated with biological research. In his comments, Robert Pollack addresses the need for improved safety protocols and stricter controls in laboratories working with potentially hazardous biological agents. He emphasizes the uneven standards in the certification and handling of biological materials, such as primary monkey cells and hybrid viruses, and the inconsistencies in the availability of certified, safe biological products like poliovaccine. Pollack calls for immediate action to implement safer practices, particularly in laboratories that handle dangerous viruses, cells, or animals. He also highlights the necessity for central certification of virus seed stocks and suggests that governmental and private research agencies must provide the necessary funds to ensure safety in research. Pollack warns that without adequate funding and safety measures, research may either continue with unnecessary risks or be halted entirely. Additionally, he stresses the importance of conducting prospective studies on the incidence of disease, including cancers, in laboratory workers to assess the potential harm of the agents being studied
- …
