Manufactured CeO2 nanomaterials (CeO2-MNMs) are used for a wide variety of applications including diesel fuel additives and chemical/mechanical planarization media. To test the effects of CeO2-MNM surface coating charge on to model organism Caenorhabditis elegans, we synthesized 4 nm CeO2 with cationic (DEAE-), anionic (CM-), and neutral (DEX) coatings. In L3 nematodes exposed for 24 hours, DEAE-CeO2 induced lethality at lower concentrations than CM- or DEX-CeO2. Feeding slightly decreased CeO2 toxicity, regardless of coating. In L2 nematodes exposed for 48 hours with feeding, DEAE-CeO2 caused lethality at the lower concentrations as compared to CM- and DEX-CeO2. Sublethal effects were measured by observing reproduction and oxidative/nitrosative protein damage. Low concentrations of DEAE-CeO2 induced similar reductions as CM- and DEX-CeO2 that were two orders of magnitude higher. Using immunochemical slot blots to explore oxidative/nitrosative stress, no treatments produced significant changes in protein carbonyl or 3-nitrotyrosine formation; however, the statistical power of our assay was low. All treatments caused large but not statistically significant increases in protein carbonyl levels. DEAE-CeO2 exposure caused a significant reduction in 4-hydroxy-2-nonenol levels. This research suggests that cationic coatings render CeO2 significantly more toxic to C. elegans than neutral or anionic coatings.

One of the most unforgiving processes in nature is that of Muller's ratchet, a seemingly irreversible accumulation of deleterious mutations that all organisms have to deal with or face extinction. The most obvious way to avoid fitness collapse is recombination, though asexual populations usually do not have the luxury of recombining freely.  With the aid of computational and mathematical models, we have studied other situations where this threat is averted and the organism can survive the ratchet. The results show that a ratchet where all mutations have the same deleterious fitness effect is very effectively stalled for large effects. However, if mutations are allowed to have a broad range of effects, the fitness-loss rate can be substantial even with the same mean effect as the one-type ratchet, but we have  identified parameter regions where even the broad-range effects are effectively stopped. The fitness-loss from a ratchet is very sensitive to the mutation rate and a mutation that increases the mutation rate (mutator) can easily start an otherwise stalled ratchet. Large effect mutators are heavily counter-selected, but smaller mutators can spread in the population. They can be stopped by reversals (antimutators), but even if the mutation rate is equilibrated in this way, there will be large fluctuations in mutation rate and even larger in the fitness-loss rate due to the feedback amplification in their coupling.    Another way of preventing the ratchet is by reversal of the deleterious mutations themselves through back-mutations or compensatory mutations. The rate required to stop the ratchet using only back-mutations before the fitness collapses is very large. A detailed comparison between the deleterious mutations in the ratchet and in a sexual population was made and the difference was found to be greatest for large populations with large genomes. There are obviously many ways to survive the ratchet, but even more ways to drive a species to extinction by enhancing and speeding up the ratchet. By modelling and testing the ratchet for numerous different situations, we show the effects of some of these threats and benefits.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O principal objetivo do presente trabalho consiste em demonstrar que, segundo a Lógica, a Filosofia do Espírito e a Estética de Hegel, os âmbitos da natureza e do espírito, tal como descritos pelo autor, não podem ser concebidos como âmbitos isolados entre si, mas devem ser tidos antes como domínios interligados por dois importantes fundamentos conceituais, a saber: em primeiro lugar, Hegel concebe tanto o espírito quanto a natureza como modos de manifestação da Ideia Absoluta; em segundo lugar, Hegel define a natureza como o espírito alienado de si. Sendo assim, investigaremos em que consiste tal estado de alienação e o modo como o mesmo se torna evidente em meio às considerações do autor sobre a natureza, bem como o modo pelo qual tal alienação é, por assim dizer, superada pelo próprio espírito imanente à natureza, superação esta que o conduz ao reino da consciência. Entretanto, é importante ter em mente desde já que a suspensão deste estado de alienação não ocorre de forma repentina: ao contrário, a assim chamada des-alienação do espírito se dá por meio de um processo gradual, onde a essência espiritual da natureza se torna mais manifesta à medida que o auto-movimento torna-se perceptível como algo imanente aos seres naturais, tendo como ápice de sua manifestação a natureza orgânica. Nesta forma de existência natural, a alma ― termo cunhado a partir do termo latino anima, a fonte de animação dos organismos em geral ― lhes empresta a vitalidade que lhes é própria, vitalidade esta que, como veremos, consiste na forma de expressão mais elevada da presença do espírito na natureza. / This dissertation aims at demonstrating that, according to Hegels Logic, Philosophy of Spirit and Aesthetics, the domains of nature and spirit cannot be conceived as two completely isolated domains, but rather as domains which are intimately connected by two important conceptual grounds, namely, the fact that Hegel conceives both nature and spirit as two modes of manifestation of the Absolute Idea and the fact that Hegel defines nature as the spirit existing as alienated from itself. In this way, we shall analyze such state of alienation, in order to clarify exactly what it is and how it expresses itself among the authors descriptions of the natural realm; besides, we shall also investigate how such alienation is, so to speak, overcome by the spirit lying within the essence of nature, which leads to the rise of consciousness. However, according to Hegel, the overcoming of such state of alienation is not something that happens instantly: on the contrary, it consists in a gradual process, in which the immanent spiritual essence of nature unfolds itself and becomes more clearly manifested as the property of self-movement begins to be acknowledged as something inherent to the natural beings, organic nature being the apex of spirits manifestation within nature. In the realm of organic nature, the soul a term that is related to the Latin word anima, the source of animation of organisms in general grants them the vitality which characterizes them as living beings; as we shall see, this vitality is the most elevated way of the spirits manifestation within nature.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O principal objetivo do presente trabalho consiste em demonstrar que, segundo a Lógica, a Filosofia do Espírito e a Estética de Hegel, os âmbitos da natureza e do espírito, tal como descritos pelo autor, não podem ser concebidos como âmbitos isolados entre si, mas devem ser tidos antes como domínios interligados por dois importantes fundamentos conceituais, a saber: em primeiro lugar, Hegel concebe tanto o espírito quanto a natureza como modos de manifestação da Ideia Absoluta; em segundo lugar, Hegel define a natureza como o espírito alienado de si. Sendo assim, investigaremos em que consiste tal estado de alienação e o modo como o mesmo se torna evidente em meio às considerações do autor sobre a natureza, bem como o modo pelo qual tal alienação é, por assim dizer, superada pelo próprio espírito imanente à natureza, superação esta que o conduz ao reino da consciência. Entretanto, é importante ter em mente desde já que a suspensão deste estado de alienação não ocorre de forma repentina: ao contrário, a assim chamada des-alienação do espírito se dá por meio de um processo gradual, onde a essência espiritual da natureza se torna mais manifesta à medida que o auto-movimento torna-se perceptível como algo imanente aos seres naturais, tendo como ápice de sua manifestação a natureza orgânica. Nesta forma de existência natural, a alma ― termo cunhado a partir do termo latino anima, a fonte de animação dos organismos em geral ― lhes empresta a vitalidade que lhes é própria, vitalidade esta que, como veremos, consiste na forma de expressão mais elevada da presença do espírito na natureza. / This dissertation aims at demonstrating that, according to Hegels Logic, Philosophy of Spirit and Aesthetics, the domains of nature and spirit cannot be conceived as two completely isolated domains, but rather as domains which are intimately connected by two important conceptual grounds, namely, the fact that Hegel conceives both nature and spirit as two modes of manifestation of the Absolute Idea and the fact that Hegel defines nature as the spirit existing as alienated from itself. In this way, we shall analyze such state of alienation, in order to clarify exactly what it is and how it expresses itself among the authors descriptions of the natural realm; besides, we shall also investigate how such alienation is, so to speak, overcome by the spirit lying within the essence of nature, which leads to the rise of consciousness. However, according to Hegel, the overcoming of such state of alienation is not something that happens instantly: on the contrary, it consists in a gradual process, in which the immanent spiritual essence of nature unfolds itself and becomes more clearly manifested as the property of self-movement begins to be acknowledged as something inherent to the natural beings, organic nature being the apex of spirits manifestation within nature. In the realm of organic nature, the soul a term that is related to the Latin word anima, the source of animation of organisms in general grants them the vitality which characterizes them as living beings; as we shall see, this vitality is the most elevated way of the spirits manifestation within nature.

Com o advento da agricultura ampliou-se a produção alimentar e os bens de consumo, no entanto, os riscos ambientais também foram maximizados em função da adoção de técnicas produtivas baseadas no uso intensivo de insumos agrícolas. Esta problemática é mundial, embora mais evidenciada nos países em desenvolvimento e que tem, na produção agrícola, a base de sua economia. O Brasil enquadra-se nesta situação e desde 2009 é considerado o maior consumidor de agrotóxicos do mundo, criando um cenário de risco ambiental e de saúde humana. Os efeitos ambientais, base deste estudo, estão relacionados não somente à perda de espécies não-alvo, uma vez que os agrotóxicos não são seletivos, mas também as alterações em nível ecossistêmico, a qual se relaciona com as perdas das funções e dos serviços gerados pelos sistemas naturais. Adiciona-se a esta complexidade, a forma de ação de cada agrotóxico, a distribuição dos mesmos nos diferentes compartimentos (ar, solo e água), o período de permanência de cada um, as relações sinérgicas decorrentes das interações entre diferentes produtos, a formação de subprodutos no processo de degradação, entre outros fatores, como as diferenças existentes entre o ingrediente ativo e a formulação comercial, na qual existem os chamados ingredientes inertes em sua composição, os quais podem ser muito mais tóxicos para espécies e ecossistemas. Considerando esta abordagem, a presente pesquisa foi desenvolvida com base na realidade de um local de referência, o município de Bom Repouso (MG/BR), no qual a intensificação da produção de morango e batata tem trazido uma série de riscos sociais e ambientais. Semelhante a outras regiões produtivas do país, o uso de agrotóxicos é recorrente, amplo e irrestrito, com destaque para as formulações comerciais Kraft®36EC e Score®250EC, as quais, juntamente com seus respectivos ingredientes ativos (abamectina e difenoconazol), foram avaliadas por meio de testes de toxicidade com espécies de diferentes níveis tróficos representativas de um ecossistema aquático, gerando informações que foram avaliadas em nível de espécie e de ecossistema, simulando o cenário de aplicação dos produtos no local de referência. Os resultados obtidos permitiram concluir sobre as diferenças de sensibilidade das espécies e quais seriam as mais indicadas para se avaliar os efeitos tóxicos de ambos os agrotóxicos; os efeitos diferenciados entre a formulação comercial e os ingredientes ativos; bem como as respostas em termos de espécies e de ecossistemas, demonstrando a necessidade de que ambas as análises sejam consideradas na avaliação de risco ecológico. / With the advent of agriculture, food production and consumer goods has expanded, however, environmental risks were also maximized due to the adoption of production techniques based on intensive use of agricultural inputs. This worldwide problem is more evident in developing countries which have agricultural production as the basis of its economy. Brazil is into this situation and since 2009 it is considered the largest consumer of the world\'s pesticides, creating a scenario of environmental risk and human health. The environmental effects from this study are related not only to loss of non-targeted species, since pesticides are nonselective, but also changes in the ecosystem level, which relates to the loss of functions and services generated by natural systems. Add to this complexity, the mode of action of each pesticide, their distribution in the different compartments (air, soil and water), the period of stay of each, the synergistic relationships resulting from interactions between different products, the formation of by-products in the process of degradation, among other factors, such as differences between the active ingredient and the commercial formulation in which there are so-called ingredients inert in the composition, which may be more toxic to species and ecosystems. Considering this approach, this research was developed based on the reality of a reference site, the municipality of Bom Repouso (MG/BR), in which the intensification of production of strawberry and potato has brought a series of social and environmental risks. Similar to other productive regions of the country, the use of pesticides is recurrent, widespread and unrestrained, highlighting the commercial formulations Kraft®36EC and Score®250EC, which, along with their active ingredients (abamectin and difenoconazole) have been evaluated by toxicity tests with representative species of different trophic levels of an aquatic ecosystem, generating information that have been evaluated at the species level and ecosystem, simulating the application scenario of the products on the reference location. The results showed differences on the sensitivity of species and what are the most appropriate to evaluate the toxic effects of both pesticides; the differential effects between the commercial formulation and the active ingredients; as well as the responses in terms of species and ecosystems, demonstrating the need for both to be considered in ecological risk assessment.

No description available.

This thesis focuses on the role and historical development of strategies of experimental domestication in scientific knowledge production, with a particular focus on the function of the laboratory strains known as 'wild types' in the model organism systems of classical genetics, where they play the role of standing in for the 'natural' instance of the species so that variation may be measured. As part of establishing how lab wild types came to assume this role, I have situated them within a much longer historical trajectory that tracks how changes in the manner that European intellectual traditions conceptualised the domestic-wild divide were linked to the development of new forms of scientific domestication and knowledge production. These new developments required that existing domesticating practices be intensified, expanded and analogised in order to better control, capture and comprehend 'wild' nature. My first two chapters introduce the domestic-wild divide by discussing both contemporary and ancient interpretations of it. In my third and fourth chapter, I explore the roots of the knowledge regime of European scientific domestication. I highlight Francis Bacon's campaign to use knowledge of domesticating practices to restore human dominion, before showing how Linnaeus later re-conceptualised the natural economy as an autonomous order and original order, with domestication reinterpreted as an artful transformation of nature requiring human maintenance to prevent reversion to its wild 'natural state'. I identify this idea of the wild as original and the domestic as derivative and artificially maintained as the basis of the original wild type concept. In my fifth chapter, I discuss Darwin's attempt to unite the domestic and wild under common laws of variation and selection, including his argument that reversion was simply a product of a return to ancestral conditions of existence. I observe that Darwin's theory of variation was problematic for the effort to bring wild nature under controlled conditions for study, so in my sixth and seventh chapters discuss how this difficulty was resolved, first by experimental naturalists both before and after Darwin who utilised vivaria and microscopes to bring pieces of nature indoors, and then by Weismann and Galton's sequestration of heredity, which helped persuade scientists that domestication was not in itself a cause of germinal variation. In my eighth and ninth chapter, I detail how sequestration led the early Mendelians de Vries and Bateson to assume that wild types could be brought into the lab from nature and purified into true-breeding strains. I discuss their differing atomist and interactionist perspectives on wild type, with de Vries favouring 'elementary species' as units of nature, whereas Bateson held wild types and mutants to represent normal and abnormal forms of the species respectively. In my last chapter, I cover the replacement of Bateson's interactionist genetics by the reductionist genetics of the Morgan group and argue that this led to a disintegration of wild types into their component genes. I conclude with a discussion of what wild type strains in classical genetics were meant to be representative of, and end by establishing that whilst these strains may not wholly be representative of their species, they are nonetheless useful tools for scientific knowledge production.

No description available.

This thesis deals with promoting of the interests in the area of genetically modified organisms. The aim is to analyze the activities of interest groups in the area and affect different approach of governments to GMO in the USA and Europe. The work is structured into four parts. The first chapter theoretically defines interest groups and lobbying. The second chapter is devoted to genetically modified organisms and the differences between the EU and the USA in the legislation, the extent of cultivation and the approach of governments. The third chapter deals with Monsanto - the company that dominates the amount of interest groups in this area. The fourth chapter presents a case study of the problem of genetically modified maize in Europe. Just on the case of genetically modified maize can be seen in the European Union activities interest groups, approach of member states and European Union approach.

Neste trabalho foram caracterizadas molecularmente e inferidas as relações filogenéticas de 14 isolados brasileiros de Acanthamoeba, provenientes de casos de ceratite, e 8 isolados da ATCC (4 de ceratite e 4 ambientais). Foram utilizados inicialmente os métodos de RAPD, RFLP de DNA genômico total e RFLP do SSU rDNA. Apesar de revelar a alta variabilidade genética em Acanthamoeba, estes métodos permitiram estabelecer grupos bem definidos de isolados mais similares geneticamente. O seqüenciamento do SSU rDNA permitiu a inferência da filogenia entre os isolados utilizados nesse estudo em relação àqueles presentes na literatura, que estão distribuídos em doze tipos de seqüência deste gene. Dentre os 17 isolados de ceratite presentes em nosso estudo, 16 apresentaram SSU rDNA tipo T4 (anteriormente já fortemente correlacionado à ceratite) e um deles constitui um novo tipo de seqüência. Dois dos 4 isolados ATCC (ambientais) cujas seqüências ainda não haviam sido determinadas também apresentaram novos tipos de SSU rDNA, enquanto outros 2 apresentaram o tipo T4. / In this work we performed the molecular phylogeny and characterization of 22 Acanthamoeba isolates, 14 Brazilian keratitis isolates and 8 from ATCC, 4 keratitis and 4 environmental isolates. In spite of the extensive genetic variability disclosed by RAPD, total genomic DNA RFLP and SSU rDNA RFLP techniques, these methods enabled us to group some isolates in well defined clusters of genetically more related organisms. Sequencing of SSU rDNA allowed inference of the phylogeny of our isolates with those present in the literature, which are distributed through 12 sequence types of this gene. Among the 17 keratitis isolates of our study, 16 presented SSU rDNA of type T4 (previously found to be strongly correlated to keratitis), and one was assigned to a new sequence type. Of the 4 isolates from ATCC whose sequences were previously undetermined, the two environmental isolates also constituted new sequence types, while the two keratitis isolates were assigned to type T4.