Darbe tiriamas Herakleito kosmologijos ir stoikų fizikos santykis. Analizuojamos paralelės, skoliniai, bei novatoriški bruožai. Tiek Herakleito, tiek Ankstyvosios ir Viduriniosios Stojos atstovų raštai žuvę, yra surinkti ir išleisti tik fragmentai (M. Adomėnas 1995; I. Arnim1903-1924). Remiantis Herakleito ir stoikų filosofijos tyrinėtojų darbais (F. Ch. Kessidi 1982; Ch. H. Kahn 1966; M. Boeri 2001; A. A. Stoliarov 1999), darbe teigiama, kad Herakleitas turėjo žymios įtakos stoikų kosmologijai. Stoikai kaip ir Herakleitas mąstė pasaulį akcentuodami judėjimą, pasikeitimą ir kokybinę įvairovę, tačiau Stojos teorija pasaulio „darbinei schemai“ suteikia daugiau sistematiškumo ir struktūros. Stoikai savo fizikoje iš Herakleito perėmė vienintelio, tačiau vis atsinaujinančio ir cikliškai besivystančio kosmo sampratą, ugnies, kaip aktyvaus formuojančio principo koncepciją, bei logo - visuotinio kaitos kosme dėsnio sampratą, tačiau visos šios sąvokos, stoikų buvo praplėstos ir/arba modifikuotos. Taip pat magistro darbe analizuojamos naujos, stoikų sukurtos sąvokos: tvirtinimas, kad „viskas yra kūnas“, išreiškė originalų požiūrį į kosmą, „pneuma“[τό πνεύμα] – kosminė jėga, kurianti pasaulį, esantį nuolatinėje dinamikoje, Logas kaip ir Dievas, - materialūs. Sukuriama teorija apie „simpatiją“[συμπάθεια], - užtikrinančia visų kosmo dalių tarpusavio sąveiką. Darbe analizuojamos Stojos atstovų pateiktos... [toliau žr. visą tekstą] / This Master thesis studies the relationship between Heraclitus‘ Cosmology and Stoic Physics. The parallels between both writings, as well as appropriations and innovative ideas are discussed. Both Heraclitus‘ and Early and Middle Stoa‘s writings are lost and only fragments have survived and been published (M. Adomėnas 1995; I. Arnim1903-1924). Following the work of the researchers of Heraclitus and Stoic Philosophy (F. Ch. Kessidi 1982; Ch. H. Kahn 1966; M. Boeri 2001; A. A. Stoliarov 1999) the thesis argues that Heraclitus had a significant influence on Stoic Physics. The Stoics as well as Heraclitus contemplated the world by emphasising movement, change and qualitative diversity, while Stoics theory provided world’s “working scheme” with a better system and structure. In their Physics, the Stoics took from Heraclitus the idea of a single, continually resuming and cyclically developing cosmos, the conception of fire as an active and formative principle, and logos – the concept of a universal law of change in the cosmos. However all these concepts were extended and/or modified by the Stoics. Moreover, the thesis analyses new concepts originated by Stoics; the statement that “everything is corporeal” expressing an original view of cosmos, the notion of „pneuma“[τό πνεύμα] – the cosmic power that generates the world in constant movement, and the argument that Logos as well as God are material. The theory of “sympathy” [συ&#956... [to full text]

Made available in DSpace on 2015-03-03T15:15:27Z (GMT). No. of bitstreams: 1 TharcisyoSSD_DISSERT.pdf: 3303211 bytes, checksum: cec9a1421d7e1a74109ea2385531baa3 (MD5) Previous issue date: 2012-03-02 / This study proposes an observing program focused on the investigation of the stellar magnetism and dynamo evolution in cool active solar-like stars. More mainly in the solar analogs and twins. Observations of stars of our base were carried out with two spectropolarimeter (ESPaDOnS@CFHT and NARVAL@TBL). The analyse of stars in stage different allows an understanding of the dependence of magnetic activity on basic stellar parameters such as rotation, mass, age and depth of the convection zone. This study provides measures necessary for testing dynamo theories. The 65 targets for this project are solar type stars with mass spanning from 0:9 M=Mfi 1:075 solar masses and at different evolutionary stages. Our two main science objectives were, (i) To determine how the magnetic field evolved from the ZAMS to the TO (turn off) for stars with 0:9 M=Mfi 1:075; (ii) To determine the impact of convective depth and rotation on magnetic of cool stars of solar type. The main result from this study was the characterization of the dependence of magnetic field intensity as function of age, Rossby number and the convective zone deepening. This context, the availability of ESPaDOnS and NARVAL opens an exceptional possibility to study the magnetic properties of Sun-like stars by means of spectropolarimetric observations / Este estudo prop?e um programa observacional focado na investiga??o da evolu??o do magnetismo estelar e do d?namo em estrelas frias, ativas e do tipo-solar. Mais precisamente nas estrelas an?logas e g?meas solares. As observa??es das estrelas da nossa base foram realizadas com dois espectropolar?metros (ESPaDOnS@CFHT e NARVAL@TBL). A an?lise das estrelas em diferentes est?gios permite uma compreens?o da depend?ncia da atividade magn?tica em fun??o de par?metros estelares b?sicos como, por exemplo, a rota??o, a massa, a profundidade da zona convectiva e a idade. Este estudo fornece medidas necess?rias para testar ? teoria do d?namo. Os 65 objetos utilizados nesse trabalho tratam-se de estrelas do tipo solar, com massa no intervalo de 0:9 < M=M < 1:075 e em diferentes est?gios evolutivos. Nossos dois principais objetivos cient?ficos foram, (i) Determinar como o campo magn?tico evoluiu a partir da sequ?ncia principal de idade zero (ZAMS) at? o turn off, num intervalo de massa 0:9<M=M,<1:075; (ii) Determinar o impacto da profundidade da zona convectiva e da rota??o no magnetismo das estrelas frias do tipo solar. O principal resultado deste estudo foi a caracteriza??o da depend?ncia da intensidade do campo magn?tico com a idade, com o n?mero de Rossby e com o aprofundamento da zona convectiva. Neste contexto, a disponibilidade do ESPaDOnS e NARVAL abre uma excepcional possibilidade para estudarmos as propriedades magn?ticas das estrelas do tipo-solar atrav?s das observa??es espectropolarim?tricas.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-03-09T19:50:49Z No. of bitstreams: 1 TharcisyoSaESousaDuarte_TESE.pdf: 4000536 bytes, checksum: 76f14cacb9f32138dca1e02cb150ad3b (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-03-13T19:38:20Z (GMT) No. of bitstreams: 1 TharcisyoSaESousaDuarte_TESE.pdf: 4000536 bytes, checksum: 76f14cacb9f32138dca1e02cb150ad3b (MD5) / Made available in DSpace on 2017-03-13T19:38:21Z (GMT). No. of bitstreams: 1 TharcisyoSaESousaDuarte_TESE.pdf: 4000536 bytes, checksum: 76f14cacb9f32138dca1e02cb150ad3b (MD5) Previous issue date: 2016-05-20 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O estudo das estrelas do tipo-solar inclui naturalmente as estrelas an?logas e g?meas, que s?o estrelas id?nticas ao Sol. Estes objetos desempenham um papel fundamental no ?mbito da astrof?sica moderna, principalmente, na investiga??o da nossa estrela como um objeto comum. Dentre os diversos par?metros f?sicos observ?veis, a atividade magn?tica e cromosf?rica - para um conjunto de estrelas muito similares ao Sol (an?logas e g?meas) - s?o essenciais para compreendermos a evolu??o din?mica da atividade estelar em escalas de tempo da ordem de v?rios bilh?es de anos, isto ? tempo de vida de uma estrela do tipo-solar sobre a sequ?ncia principal. Neste trabalho, entre outros aspectos, investigaremos as rela??es existentes entre o per?odo de rota??o, abund?ncia de l?tio, atividade magn?tica e cromosf?rica, massa e idades destes grupos de estrelas. Analisaremos ainda as determina??es das idades de acordo com a t?cnica da girocronologia. O objetivo principal do nosso trabalho ? investigar a lei de decaimento de cada um dos destes par?metros com base em uma ampla amostra de estrelas classificadas como an?logas e g?meas solares. Nossos resultados deram origem a quatro publica??es em revistas indexadas, dos quais dois j? se encontram em modo ?impress?. Estes resultados mostram que as leis de evolu??o (decaimento da abund?ncia de l?tio, da rota??o e do campo magn?tico) s?o fortemente dependentes do tipo-estelar, mostrando-se mais nitidez para as estrelas an?logas e g?meas. / The interest in studying the objects similar to the Sun, stars labeled as solar-type stars, analogs and solar twins, brings in its essence an attempt to end out another reference star and, furthermore, provides an investigation of evolutionary dynamic of our star as a function of various parameters. For this, we used three distinct samples of observable data, 170 solar-type stars from BCool catalog and observed with spectropolarimeters ESPaDOnS e NARVAL, 88 solar-twin stars of HARPS surveys, and 20 solar-analog stars from Kepler. From these data, we have investigated mainly the correlation among the rotation period, lithium abundance and stellar age. For the BCool stars and solar-twin from HARPS, we have used the rotation period determined through of chromospheric activity, in the case of Kepler solar analogs, the rotation period it is derived from photometric modulation. The lithium abundance for most of the solar-type and solar-twin stars have been collected from literature, while for the solar analogs, the lithium abundance were determined in the LTE regime using Kurucz atmospheric models and the MOOG code. For stellar age, we have used the gyrochronology method, which was calibrated using the Sun and a selection of open clusters, to redetermine them and comparing them with those derived from standard isochronal. Our results indicate that exist a decay law for the rotation period as a function of lithium abundance. This correlation becomes more clear for the solar-analog and solartwin stars, even the rotation period being determined through distinct mechanisms for each case. For stellar ages, measured from standard isochronal and gyrochronology, we realized that they diverge considerably when the stars are older than the Sun. This result has also been investigated by van Saders et al. (2016) and reect our limitation about thestellar evolution and mixing mechanisms. Our work has resulted in five publications in indexed journals, two already in print format, one recently submitted and other in final stage of conclusion.