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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Evolutionary novelty : a philosophical and historical investigation

Racovski, T. January 2019 (has links)
Evolutionary novelty, the origin of new characters such as the turtle shell or the flower, is a fundamental problem for an evolutionary view of life. Accordingly, it is a central research topic in contemporary biology involving input from several biological disciplines and explanations at several levels of organization. As such it raises questions relative to scientific collaboration and multi-level explanations. Novelty is also involved in theoretical debates in evolutionary biology. It has been appropriated by evo-devo, a scientific synthesis linking research on evolution and development. Thanks to its focus on development, evo-devo claims to explain the mechanistic origin of novelties as new forms, while the Modern Synthesis can only provide statistical explanation of evolutionary change. The origin of an evolutionary novelty is a historical emergence of a new character involving form and function. I focus on three neglected dimensions of the problem of novelty, the functional-historical approach to the problem, research on novelty in the Modern Synthesis era and novelty in plants. I compare the evo-devo approach to novelty to a functional-historical approach of novelty. I focus on its origin in Darwin and its presence in the Modern Synthesis. The comparison of the two approaches reveals distance between conceptual frameworks and proximity in explanatory practices. This is partly related to unwarranted conceptual opposition. In particular, I list several ways of distinguishing novelty and adaptation, some of which are not conceptually sound. I then focus on the relation between novelty and adaptation in the Modern Synthesis era, and on the relation of novelty to other fundamental biological problems (speciation, origin of higher taxa, complexity). Pushing this approach further, I challenge the view that the Modern Synthesis excluded development and reached a hardened consensus. Finally, I analyse how Günter Wagner's developmental theory of novelty applies to novelties in plant.
52

Evo Morales e os horizontes da hegemonia nacional-popular e indigenismo na Bolívia em perspectiva comparada

Cunha Filho, Clayton Mendonça January 2009 (has links)
CUNHA FILHO, Clayton Mendonça. Evo Morales e os horizontes da hegemonia nacional-popular e indigenismo na Bolívia em perspectiva comparada. 2009. 86f. Dissertação (Mestrado) - Instituto Universitário de Pesquisas do Rio de Janeiro, Curso de Ciências Humanas, Rio de Janeiro, 2009. / Submitted by Hanna Sandy (nannybells@gmail.com) on 2016-12-20T13:27:39Z No. of bitstreams: 1 2009_dis_cmcunhafilho.pdf: 558537 bytes, checksum: 2fc39f0230d065ab5edce77a3559c148 (MD5) / Approved for entry into archive by Márcia Araújo (marcia_m_bezerra@yahoo.com.br) on 2016-12-22T11:08:04Z (GMT) No. of bitstreams: 1 2009_dis_cmcunhafilho.pdf: 558537 bytes, checksum: 2fc39f0230d065ab5edce77a3559c148 (MD5) / Made available in DSpace on 2016-12-22T11:08:04Z (GMT). No. of bitstreams: 1 2009_dis_cmcunhafilho.pdf: 558537 bytes, checksum: 2fc39f0230d065ab5edce77a3559c148 (MD5) Previous issue date: 2009 / The present dissertation seeks to understand the way through which the indianist and national-popular elements articulate themselves in the current historical block led by the government of Evo Morales and to compare it under this point of view with five previous Bolivian critical conjunctures. The underlying hypothesis of this work is that the turmoil of the years 2000-2005 marked a collapse in the hegemony of the previous historical block and the ascension of a counter-hegemonic movement that was able to rearticulate itself through the redemption of the memory from the national-popular and indigenist horizons present throughout Bolivian history and especially in the 20th Century. The comparison with the previous critical conjunctures seeks precisely to comprehend the deeper roots that allowed the agglutination of the present historical block and its claim of legitimacy. Due to the consensually recognized historical importance in the Bolivian and bolivianist literature and to the influences in the present political conjuncture, the hegemony crisis of the transition to democracy period, the military regime of Ovando and Torres, the 1952 Revolution, the government of Gualberto Villarroel and the Chaco War and Military Socialism of the 1930s were chosen for comparison. And at last, I conclude by resuming the ideas underlying the comparison between the current historical block and its preceding constitutive moments and how these influence and in some ways determine the nature of the present political process and its hegemonic horizons. / A presente dissertação busca compreender o modo como se articulam no atual bloco histórico boliviano liderado pelo governo de Evo Morales os elementos de nacionalpopular e indigenismo e compará-lo sob esse ponto de vista com cinco conjunturas críticas bolivianas anteriores. A hipótese subjacente ao trabalho é que o turbulento quinquênio de 2000-2005 marca um colapso da hegemonia do bloco histórico anterior e a ascensão de um movimento contra-hegemônico que logrou se rearticular baseado no resgate da memória dos horizontes de nacional-popular e indigenismo presentes ao longo da história do país e em especial no século XX. A comparação com as conjunturas críticas anteriores busca justamente compreender as raízes mais profundas que permitiram a aglutinação do atual bloco histórico e sua reivindicação de legitimidade. Pela importância histórica consensualmente reconhecida na bibliografia boliviana e bolivianista e pelas influências na atual conjuntura política, foram escolhidos para comparação a crise hegemônica durante a redemocratização, o regime militar de Ovando e Torres, a Revolução de 1952, o governo de Gualberto Villarroel e a Guerra do Chaco e o Socialismo Militar dos anos 1930. E por último, concluo retomando algumas das ideias subjacentes na comparação do atual bloco histórico com seus momentos constitutivos precedentes e como estes influenciam e em alguma medida determinam a natureza do processo político atual em seus horizontes hegemônicos.
53

Role of KNOX genes in the evolution and development of floral nectar spurs

Box, Mathew S. January 2010 (has links)
A key question in biology is how changes in gene function or regulation produce new morphologies during evolution. The nectar spur is an evolutionarily labile structure known to influence speciation in a broad range of angiosperm taxa. Here, the genetic basis of nectar spur development, and the evolution of differences in nectar spur morphology, is investigated in Linaria vulgaris and two closely related species of orchid, the primitively longer-spurred Dactylorhiza fuchsii, and more derived short-spurred D. viridis (Orchidinae, Orchidaceae). Despite considerable morphological and phylogenetic differences, nectar spur ontogeny is fundamentally similar in each of the study species, proceeding from an abaxial bulge formed on the ventral petal relatively late in petal morphogenesis. However, spur development is progenetically curtailed in the short-spurred orchid D. viridis. In each case spur development involves class 1 KNOTTED1-like homeobox (KNOX) proteins. KNOX gene expression is not restricted to the spur-bearing petal, indicating that additional components are required to define nectar spur position, e.g. canonical ABC genes, determinants of floral zygomorphy, and additional (currently unknown) factors. However, constitutive expression of class 1 KNOX proteins in transgenic tobacco produces flowers with ectopic outgrowths on the petals, indicating that KNOX proteins alone are, to some degree, capable of inducing structures similar to nectar spurs in a heterologous host. Interestingly, KNOX gene expression is high in the ovary of all study taxa, suggesting that KNOX proteins may also have been involved in the evolution of this key angiosperm feature. Although principally involved in maintaining indeterminacy in the shoot apical meristem (SAM), members of the KNOX gene family have been co-opted in the evolution and development of compound leaves where they suppress differentiation and extend the morphogenetic potential of the leaf. A similar model is presented here to explain the role of KNOX proteins in nectar spur development. Co-option of KNOX gene expression to the maturing perianth delays cellular differentiation, facilitating the development of the nectar spur but requiring additional, unknown factors, to determine nectar spur fate. As facilitators of nectar spur development, changes in the spatio-temporal patterns of KNOX gene expression may alter the potential for nectar spur development and explain the critical length differences observed between the orchids D. fuchsii and D. viridis (and among other angiosperm taxa). Taken together, the available data indicate that KNOX genes confer a meristematic state upon plant tissues in a variety of morphogenetic contexts, making the gene family a potentially versatile tool to mediate a wide variety of evolutionary transformations.
54

Efektivní plánování investic do technologií pro energetické využití odpadů / Effective Investment Planning in Waste-to-Energy Systems

Šomplák, Radovan January 2016 (has links)
PhD thesis deals with the application of the simulation and optimization methods in the waste-to-energy field. An introduction describes the current state of the waste management in the EU with the focus on the Czech Republic. In the following chapter the evaluation criteria for investment intentions and the basic principles of stochastic programming are discussed. The core of the work lays in the mathematical models for the planning and operation of the process plants as well as in the mathematical models for the waste collection. The transportation problem involves all considered technological elements and therefore it is possible to simulate the waste streams between the producers and processors. This approach is demonstrated with five case studies. In the first three studies the calculations for the potential investor are presented. The main outcome of these case studies is the determination of the level of attractiveness of investment and the identification the greatest risks. Another case study is devoted to an analysis with the focus on perspective of government policies and in the last case study the issue of the waste management is analyzed in detail from the perspective of the waste producers. Developed computational tools are flexible and can be further developed and adapted based on the objectives of the specific tasks.
55

Tracing Bolivia's Swing of the Pendulum : Tracing the process of popular resistance in Bolivia.

Wenlöf, Emil January 2021 (has links)
Policy regime shift through popular societal resistance in developing countries, advocating a state-regulated economic model, has been a frequent occurrence in the 21st century, during a period where neoliberalism has dominated the world market. Scholars have brought up the framework of double movement to explain these social, economic, and political changes from free-market regimes to state-controlled regimes, claiming that it is a societal reaction to the commodification of land, labor, and money. This research poses the question of how political change can be interpreted through the lens of the concept of double movement even though a government can show positive social and economic development records, where a left-wing state-regulated market has ruled the economy. Bolivia underwent political turmoil in 2019, where the former president Evo Morales, who had brought high socioeconomic development through a state-regulated economy, was ousted by a nationwide protest. An interim conservative government took office, imposing a harsh neoliberal agenda with authoritarian features, handing over the presidency to Morales’ former party only a year later, as the party won the election. Looking at the case of Bolivia through the lens of the double movement, this research found that commodification of land, labor, and money can explain popular societal resistance in Bolivia during Morales's presidency. However, the case also proved that commodification was not the only, and potentially not even the main, reason for the overthrow of Morales. Political motives and actions, clientelism, social cleavages, respect for democratic principles, and more theoretical perspectives need to be considered to comprehend regime change by popular resistance further.
56

Revealing the Structure and Evolution of a Fruit Fly Gene Regulatory Network by Varied Genetic Approaches

Hughes, Jesse T. January 2021 (has links)
No description available.
57

Evo-Devo of the Eda pathway : from the evolution of signaling to the establishment of shape / Evo-dévo de la voie Eda : de l’évolution du signaling à l’établissement de la morphologie

Sadier, Alexa 13 December 2013 (has links)
L'observation des nombreuses espèces au sein des métazoaires permet de rendre compte de leur formidable diversité de morphologies. Ces organismes complexes acquièrent leur plan d'organisation et leurs caractéristiques propres pendant le développement embryonnaire. Au cours de celui-ci, la morphogénèse des différentes structures anatomiques est contrôlée par des réseaux complexes de gènes intervenant dans des territoires et des moments précis. Comprendre quelles modifications des voies développementales au cours de l'évolution sont responsables de cette diversité constitue un champ important de la biologie moderne : l'évo-dévo. Pour comprendre ces modifications, il est important de pouvoir étudier ces changements sur des modèles facilement accessibles et qui possèdent une grande variabilité de formes. Les phanères des vertébrés répondent à ces critères : leur nombre, leur forme et leur taille ont été des caractères très variables au cours de la diversification des mammifères et les données déjà obtenues sur la souris permettent une expérimentation aisée. De nombreuses voies de signalisation sont impliquées dans le développement des phanères, mais une en particulier, impliquée spécifiquement dans le développement des appendices ectodermiques : la voie EDA, composée d'un ligand EDA, de son récepteur EDAR et d'un adaptateur spécifique EDARADD. Dans le but de mieux comprendre le rôle de la voie EDA au cours de l’évolution des mammifères, nous avons orienté ma thèse en 2 axes : le premier vise à étudier le rôle d’Edar dans le patterning de la dent chez la souris, et le second l’impact de la perte d’une des deux isoformes d’EDARADD au cours de l’évolution des mammifères. / The observation of the numerous metazoan species highlights their wonderful morphological diversity. These complex organisms got their body plan and their specific traits during embryonic development. During development, complex gene networks that are tightly regulated through space and time, control morphogenesis. Understanding which modifications of developmental pathways are responsible for the establishment of this diversity is one of the key questions of the biological field: Evo-Devo. To understand these modifications, it is crucial to study accessible models that are representative of this diversity. To do that, ectodermal appendages are a very good model: their number, size, and shape are highly variable during mammals diversification and data had already shown that they exhibit natural variation. Numerous signaling pathways are implicated in their development but one is very specific to them: the Eda pathway and present an big interest for the study of their evolution. To better understand the role of the Eda pathway during mammals evolution, I orientated my thesis in two part: the first one study the impact of Edar in the establishment of the mouse dental tooth row and the second the impact of gain/loss of protein isoforms of the adaptor Edaradd on the evolution of this pathway.
58

Algoritmos Evolutivos aplicados ao Classificador baseado em Segmentos de Reta / Evolutive Algorithms applied to the Straight Line Segment Classifier

Rodríguez, Rosario Alejandra Medina 03 July 2012 (has links)
Nos ultimos anos o uso de tecnicas de aprendizado computacional tornou se uma das tarefas comumente realizadas, pois tem inumeras aplicacoes de reconhecimento de padroes, tais como: reco- nhecimento de voz, classificacao de texto, reconhecimento facial, diagnostico por imagens medicas, entre outras. Dessa forma, um grande numero de tecnicas que lidam com este tipo de problema tem sido desenvolvido ate o momento. Neste trabalho apresentamos uma alternativa para melhorar a taxa acerto de classificacao do classificador binario SLS, que apresentou resultados comparaveis com as SVMs. Nesse metodo, o Gradiente Descendente e utilizado para otimizar a posicao final dos conjuntos de segmentos de reta que representarao cada classe. Embora convirja rapidamente a um valor otimo, muitas vezes e possivel o algoritmo parar em uma regiao de otimos locais, que nao representa o minimo global. Dado esse problema, foram utilizados diferentes algoritmos evolutivos em combinacao com o Gradiente Descendente a fim de melhorar a acuracia do classificador SLS. Adicionalmente a aplicacao de algoritmos evolutivos na fase de treinamento do classificador SLS, foram exploradas duas propostas: (i) explorar o uso de diferente numero de segmentos de reta para representar a distribuicao de dados de cada classe. Dado que no algoritmo original do metodo SLS o numero de segmentos de reta e igual para cada classe, o qual pode significar alguma perda de acuracia ou sobreposicao dos segmentos de reta; (ii) estimar a melhor combinacao de segmentos de reta a serem usados para cada classe. O uso de diferentes quantidades de segmentos de reta por classe pode ser de ajuda na obtencao de melhores porcentagens de acerto, mas determinar uma quantidade otima que permita representar cada classe, e um trabalho dificil. Assim, usamos o algoritmo X-Means, que e um algoritmo de agrupamento, para estimar o numero de segmentos de reta. As propostas exibiram bons resultados que possibilitam a aplicacao do classificador SLS, com um algoritmo de treinamento hibrido, em problemas reais. / During the past years, the use of machine learning techniques have become into one of the most frequently performed tasks, due to the large amount of pattern recognition applications such as: voice recognition, text classification, face recognition, medical image diagnosis, among others. Thus, a great number of techniques dealing with this kind of problem have been developed until now. In this work, we propose an alternative training algorithm to improve the accuracy of the SLS binary Classifier, which produces good results that can be compared to Support Vector Machines. In that classifier, the Gradient Descent method has been used to optimize the final positions of two sets of straight line segments that represent each class. Although, this method quickly converges to an optimum, it is possible that the algorithm stops at a local optimum region, which does not guarantee a global minimum. Given that problem, we combine evolutive optimization algorithms with the gradient descent method to improve the accuracy of the SLS Classifier. In addition to our proposal of using evolutive algorithms, we also developed two proposals: (i) we explore the use of different number of straight line segments to represent the data distribution. Since the original SLS classifier algorithm uses the same number of segments for each class, which could lead to a loss of accuracy or straight line segments overlapping. So, using different number of segments could be the way to improve the accuracy; (ii) estimate the best combination of straight line segments to represent each class. Finding an optimal combination, can be a very difficult problem, so we propose the X-Means algorithm to determine the number of segments. The proposed methodology showed good results which can be used to solve some other real problems with the SLS classifier using the proposed hybrid training algorithm.
59

Las relaciones bilaterales de Bolivia y Estados Unidos durante el gobierno de Evo Morales: una lectura desde el constructivismo

García Ramírez, Elmer Alejandro 15 June 2018 (has links)
La presente tesis tiene como objetivo central demostrar mediante el uso del enfoque constructivista de las relaciones internacionales el factor que condujo al deterioro histórico de las relaciones diplomáticas entre Bolivia y Estados Unidos durante los gobiernos de Evo Morales Ayma. Del mismo modo, los objetivos secundarios son analizar las relaciones bilaterales entre Washington y la Paz desde 1952 hasta 2005, lo cual permite apreciar nítidamente los procesos de interacción entre estos Estados y con base en ello poder determinar cómo se crearon y moldearon las relaciones bilaterales entre ambos países. Así como también analizar las características de la política exterior implementada por el país altiplánico a partir de la administración de Evo Morales, con la finalidad de determinar las características de la nueva configuración de la identidad de Bolivia. En la presente investigación se postula que a raíz de la llegada al poder de Evo Morales la identidad de Bolivia experimentó una severa transformación. La nueva identidad adoptada por el país altiplánico se caracteriza por asumir una postura revisionista que pretende empoderar y rescatar elementos de la cultura andina boliviana, además de erigirse en contraposición a Estados Unidos. De esta manera, Washington pasó a percibir como una verdadera amenaza a La Paz. Lo cual por su parte explica el inusitado deterioro de relaciones diplomáticas entre ambas naciones. / Tesis
60

Pomeraj spektralnih linija helijuma u gustoj niskotemperaturnoj plazmi / Stark shift of neutral helium lines in low temperature dense plasma

Gajo Teodora 24 February 2017 (has links)
<p>Izmereni su Stark-ovi pomeraji maksimuma 8 spektralnih linija neutralnog helijuma u gustoj niskotemperaturnoj plazmi impulsnog luka. Osobine izvora plazme, sem postizanja visoke elektronske koncentracije, obezbeđuju relativno jednostavan način određivanja Stark-ovog pomeraja. Izvr&scaron;ena je dijagnostika plazme, pri čemu je određena elektronska koncentracija u intervalu od (6.2 &minus; 70) &middot; 10<sup>22</sup> m<sup>&minus;3</sup> i elektronska temperatura u intervalu (16400 &minus; 21400) K. Eksperimenatlne vrednosti Stark-ovih pomeraja upoređene su sa do sada objavljenim eksperimentalnim rezultatima kao i sa rezultatima teorijskih pristupa. Proveren je uticaj Debye-evog ekraniranja na pomeraj ovih linija. Dobijeni rezultati ukazuju na popravku Stark-ovog pomeraja uračunavanjem<br />uticaja Debye-evog ekraniranja, kao i potrebu korigovanja semiklasičnih teorijskih vrednosti elektronske sudarne polu-polu&scaron;irine i pomeraja.</p> / <p>The results of an experimental study of the Stark shifts AB of 8 neutral helium lines are presented. The plasma sour-ce was a linear pulsed arc with plasma electron&nbsp; density in the range (6.2 &minus; 70) &middot; 10 <sup>22</sup> m<sup> &minus;3</sup> and plasma temperature in the range (16400 &minus; 21400) K. Details of the experimental setup that enables a relatively quick&nbsp; Stark shift determination technique is presented. The results of these measurements are presented together with the corresponding plasma parameters and compared to other experimental and theoretical data. The influence of Debye shielding is carefully examined from the semiclassical point of view. The comparison of experimental&nbsp; results obtained in this work with the semiclassical results suggests that Debye shielding has an important role on higher electron densities. Also, based on all the available experimental data, appropriate correction factors are suggested for the semiclassical Stark shift calculations for the examined lines.</p>

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