Current rates of extinctions are estimated to be around 1000 times higher than background rates that would occur without anthropogenic impacts. These extinction rates refer to the traditional view of extinctions, i.e. numerical extinctions. This thesis is about another type of extinctions: functional extinctions. Those occur when the abundance of a species is too small to uphold the species’ ecologically interactive role. I have taken a theoretical approach and used dynamical models to investigate functional extinctions and threshold values for species’ mortality rates in ecological networks. More specifically, I have derived threshold values for focal species mortality rates at which another species or the focal species itself goes numerically extinct (Paper I-II), or transgresses some predefined threshold abundance (Paper III). If an increased mortality rate of a focal species causes another species to go numerically extinct, the focal species can be regarded as functionally extinct, since its abundance is no longer large enough to uphold its ecologically interactive role. Such functional extinctions are investigated in the first papers (Paper I-II). In the following paper, limits for both increased and decreased mortality rates of species are explored (Paper III). Paper III also extends the basic theoretical idea developed in paper I-II into a more applied setting. In this paper I develop a time series approach aimed at estimating fishing mortalities associated with a low risk that any species in a community transgresses some predefined critical abundance threshold. In the last paper (Paper IV) the community wide effect of changes in the abundance of species is investigated. In the first paper (Paper I) I investigate threshold levels for the mortality rate of species in ecological networks. When an increased mortality rate of a focal species causes another species to go extinct, the focal species can be characterized as functional extinct, even though it still exists. Such functional extinctions have been observed in a few systems, but their frequency and general patterns have been unexplored. Using a new analytical method the patterns and frequency of functional extinctions in theoretical and empirical ecological networks are explored. It is found that the species most likely to be the first to go extinct is not the species whose mortality rate is increased, but instead another species in the network. The species which goes extinct is often not even directly linked to the species whose mortality rate is increased, but instead indirectly linked. Further, it is found that large-bodied species at the top of food chains can only be exposed to small increases in mortality rate and small decreases in abundance before going functionally extinct compared to small-bodied species lower in the food chains. These results illustrate the potential importance of functional extinctions in ecological networks and lend support to arguments advocating a more community-oriented approach in conservation biology, with target levels for populations based on ecological functionality rather than the mere persistence of species. In Paper II I use the approach developed in Paper I to explore the frequency and patterns of functional extinctions in ecological networks with varying proportions of mutualistic and antagonistic (predator-prey) interactions. The general results from Paper I are also found in Paper II; that is, an increased mortality rate of one focal species often first leads to an extinction of another species rather than to an extinction of the focal species itself. Further, the frequency of functional extinctions is higher in networks containing a mixture of interaction types than in networks with only antagonistic interactions. Overall, this study generalize the findings of paper I for networks containing a variety of interaction types. To make the theoretical approaches developed in paper I-II operational in a management setting I develop a time series approach aimed at estimating ecologically sustainable fishing mortalities in a multispecies fisheries context (Paper III). An ecologically sustainable fishing mortality is here defined as a long-term fishing mortality associated with a multispecies objective which infers a low risk that any species, either the focal species itself or another species, in a community transgresses a critical biomass limit, below which the risk of recruitment failure is high. The approach is exemplified using a statistical food web model of the dominating fish stocks in the Baltic Sea. For the most abundant fish stock a counterintuitive result is found; it is more likely that the multispecies objective is met if its mortality caused by fishing is increased compared to if it is decreased. Further, simultaneous changes of the fishing mortality of a number of interacting species in the food web model shows a much narrower region of possible sustainable fishing mortalities than a single species approach, something that is not captured by current stock assessment models. Altogether these results are governed by indirect effects propagating in the community and pinpoints the need to adopt community dynamical approaches in fisheries management. The population sizes of many species in the world are declining. Negative population trends are particular pronounced in large-bodied herbivores and carnivores, species known to play important regulatory roles in many ecosystems. Although this indicates that the ecological consequence of declining populations of species might be profound, its impact on ecosystem stability remains largely unexplored. In paper IV it is therefore explored how declining populations of rare and common species affects the resilience – recovery rate – of ecological networks. An analytical approximation shows that network resilience is a function of the harmonic mean of the species’ abundances. This means that network resilience is especially sensitive to declining abundances of rare species. Consistent with this analytically derived result, a clear and positive relationship between resilience and the abundance of the rarest species in a broad spectrum of dynamical models of ecological networks is found. Together these results illustrate the potentially negative consequences of declining populations of rare species for the stability of the ecological systems in which they are embedded, and provide ecological arguments for the protection and management of rare species.

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / Os discursos políticos educacionais acerca da institucionalização da instrução elementar em Minas Gerais atravessaram todo o século XIX, apontando também como uma preocupação republicana, ora pelo discurso de impraticabilidade e ferimento aos direitos civis, ora pela defesa de seu caráter estatal e da argumentação de função civilizatória e disciplinar da população. Nesse sentido, pensar a compulsoriedade do ensino demanda uma compreensão da sua função social, o conhecimento dos agentes envolvidos e de seus interesses sobre tal medida de governo. De acordo com os defensores da obrigatoriedade do ensino no século XIX e início do XX, o intuito da educação seria formar cidadãos civilizados e instruídos. Tal perspectiva estava relacionada a um projeto de sociedade e de nação brasileira, para o qual era imprescindível formar, desde a infância, um povo disciplinado, um povo bem governado. O nosso objetivo foi analisar o tema da obrigatoriedade do ensino a partir do conceito foucaultiano de governamentalidade. Problematizando a ideia de que universalizar o acesso à educação representava apenas uma iniciativa de garantia de direitos, a hipótese que defendemos consiste na ideia de que o ensino obrigatório pode ter sido perspectivado enquanto uma estratégia de governo dos outros, de controle dos sujeitos. Partindo desse pressuposto, como efeito esperado, seria possível obter sujeito com outras atitudes, as atitudes derivadas da coação promovida pela escola. Ao legitimar a escola, o dispositivo da obrigatoriedade funcionaria como estratégia e produziria positividades. Por meio da escola e de seu caráter compulsório, tratava-se de atingir e gerir a população dos pequenos, de modo a equipá-la com os códigos mínimos do mundo civilizado, com os efeitos disciplinares correlatos.Para tanto, analisamos a legislação de Minas Gerais, impressos mineiros (Correio de Minas, Jornal do Commercio, Minas Livre, O Granbery) e a bibliografia acerca da obrigatoriedade da instrução primária, a fim de identificar traços do debate no Império e na passagem para a República, os quais foram problematizados à luz daquele conceito. A partir dessa discussão, concluímos que a obrigatoriedade do ensino é mais bem compreendida se analisada em outro registro que não seja meramente jurídico. Tal inferência aponta para a ampliação do quadro analítico acerca dessa política compulsória e dos interesses de Estado em torno dela. / The educational policy discourses about institutionalization of elementary education in Minas Gerais crossed the entire nineteenth century pointing out also as a Republican worry, noticeable through the discourse of impracticability and injury of civil rights, and either the defense of their state-owned character and the argumentation of populations civilizing and disciplinarian functions. In this sense, think compulsoriness education demands an understanding of its social function, the knowledge of agents involved and their interests around that governments measure. According to the advocates of compulsory education in the nineteenth and early twentieth centuries, the aim of education was to constitute civilized and educated citizens. This perspective was related to a project of society, included the idea of Brazilian nation, for which was essential to form, since childhood, a disciplined people, a well governed people. Our objective was to analyze the theme of compulsory education from the Foucault concept of governmentality. Questioning the idea that universal access to education represented only an initiative to guarantee rights, we defend the hypothesis that compulsory education may have been viewed as a government strategy of others, as a strategy to control subjects. Based on this presupposition, as expected effect, would be possible obtain new subjects with new attitudes, derived from coercion promoted by the school. By legitimizing the school, the obligatoriness apparatus would work as a strategy and would produce positivities. Through the school and its compulsory character, it was to reach and manage the population of small, so that to equip it with the minimum code of the civilized world, with the related disciplinary effects. For this purpose, we analyze the legislation of Minas Gerais, printed journals (Correio de Minas, Jornal do Commercio, Minas Livre, O Granbery) and the literature on the compulsory primary education in order to identify traces of the debate on empire and the transition to the Republic, which were problematized in the light of that concept. From this discussion, we conclude that compulsory education is better understood if analyzed in another record that is not purely juridical. This inference points to the enlargement of the analytical framework of this compulsory policy and state interests around it.

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / Os discursos políticos educacionais acerca da institucionalização da instrução elementar em Minas Gerais atravessaram todo o século XIX, apontando também como uma preocupação republicana, ora pelo discurso de impraticabilidade e ferimento aos direitos civis, ora pela defesa de seu caráter estatal e da argumentação de função civilizatória e disciplinar da população. Nesse sentido, pensar a compulsoriedade do ensino demanda uma compreensão da sua função social, o conhecimento dos agentes envolvidos e de seus interesses sobre tal medida de governo. De acordo com os defensores da obrigatoriedade do ensino no século XIX e início do XX, o intuito da educação seria formar cidadãos civilizados e instruídos. Tal perspectiva estava relacionada a um projeto de sociedade e de nação brasileira, para o qual era imprescindível formar, desde a infância, um povo disciplinado, um povo bem governado. O nosso objetivo foi analisar o tema da obrigatoriedade do ensino a partir do conceito foucaultiano de governamentalidade. Problematizando a ideia de que universalizar o acesso à educação representava apenas uma iniciativa de garantia de direitos, a hipótese que defendemos consiste na ideia de que o ensino obrigatório pode ter sido perspectivado enquanto uma estratégia de governo dos outros, de controle dos sujeitos. Partindo desse pressuposto, como efeito esperado, seria possível obter sujeito com outras atitudes, as atitudes derivadas da coação promovida pela escola. Ao legitimar a escola, o dispositivo da obrigatoriedade funcionaria como estratégia e produziria positividades. Por meio da escola e de seu caráter compulsório, tratava-se de atingir e gerir a população dos pequenos, de modo a equipá-la com os códigos mínimos do mundo civilizado, com os efeitos disciplinares correlatos.Para tanto, analisamos a legislação de Minas Gerais, impressos mineiros (Correio de Minas, Jornal do Commercio, Minas Livre, O Granbery) e a bibliografia acerca da obrigatoriedade da instrução primária, a fim de identificar traços do debate no Império e na passagem para a República, os quais foram problematizados à luz daquele conceito. A partir dessa discussão, concluímos que a obrigatoriedade do ensino é mais bem compreendida se analisada em outro registro que não seja meramente jurídico. Tal inferência aponta para a ampliação do quadro analítico acerca dessa política compulsória e dos interesses de Estado em torno dela. / The educational policy discourses about institutionalization of elementary education in Minas Gerais crossed the entire nineteenth century pointing out also as a Republican worry, noticeable through the discourse of impracticability and injury of civil rights, and either the defense of their state-owned character and the argumentation of populations civilizing and disciplinarian functions. In this sense, think compulsoriness education demands an understanding of its social function, the knowledge of agents involved and their interests around that governments measure. According to the advocates of compulsory education in the nineteenth and early twentieth centuries, the aim of education was to constitute civilized and educated citizens. This perspective was related to a project of society, included the idea of Brazilian nation, for which was essential to form, since childhood, a disciplined people, a well governed people. Our objective was to analyze the theme of compulsory education from the Foucault concept of governmentality. Questioning the idea that universal access to education represented only an initiative to guarantee rights, we defend the hypothesis that compulsory education may have been viewed as a government strategy of others, as a strategy to control subjects. Based on this presupposition, as expected effect, would be possible obtain new subjects with new attitudes, derived from coercion promoted by the school. By legitimizing the school, the obligatoriness apparatus would work as a strategy and would produce positivities. Through the school and its compulsory character, it was to reach and manage the population of small, so that to equip it with the minimum code of the civilized world, with the related disciplinary effects. For this purpose, we analyze the legislation of Minas Gerais, printed journals (Correio de Minas, Jornal do Commercio, Minas Livre, O Granbery) and the literature on the compulsory primary education in order to identify traces of the debate on empire and the transition to the Republic, which were problematized in the light of that concept. From this discussion, we conclude that compulsory education is better understood if analyzed in another record that is not purely juridical. This inference points to the enlargement of the analytical framework of this compulsory policy and state interests around it.

The thesis deals with the issue of Age Management and the application forms of organizations in the Czech working environment. This thesis was initially dedicated to defining the concept of Age Management and also to present its historical development. It also includes its consistency with the demographic situation. Wider attention is paid to the application of Age Management in practice and the use of specific tools and measures that are used by organizations. This paper also highlights the main benefits and importance of Age Management. There are few selected researches concerning this subject, carried out in various organizations in the European Union and in the Czech Republic. The important part of the thesis is the empirical survey, whose main target is to determine whether the selected organizations, based in Prague and operating in the private sector, have some awareness about Age Management, as well as comparing its application into practice and corporate strategy. Key words: Age Management, Age Diversity, Population Ageing, Intergenerational Cooperation, Age Discrimination.