Geologia, Geocronologia, Geoqu��mica e Petrog��nese das Rochas ��gneas Cret��cicas da Prov��ncia Magm��tica do Cabo e suas Relações com as Unidades Sedimentares da Bacia de Pernambuco (NE do Brasil)

The area studied forms a thin NNE-directed belt situated south of Recife town (Pernambuco state), northeastern Brazil. Geologically, it comprises the Pernambuco Basin (PB), which is limited by the Pernambuco Lineament to the north, the Maragogi high to the south and the Pernambuco Alagoas massif to the west, all of them with Precambrian age. This thesis reports the results obtained for the Cabo Magmatic Province (CMP), aiming the characterization of the geology, stratigraphy, geochronology, geochemistry and petrogenesis of the Cretaceous igneous rocks presented in the PB. The PB is composed of the Cabo Formation (rift phase) at the base (polymictic conglomerates, sandstones, shales), an intermediate unit, the Estiva Formation (marbles and argillites), and, at the top, the Algodoais Formation (monomictic conglomerates, sandstones, shales). The CMP is represented by trachytes, rhyolites, pyroclastics (ignimbrites), basalts / trachy-andesites, monzonites and alkali-feldspar granite, which occur as dykes, flows, sills, laccoliths and plugs. Field observations and well descriptions show that the majority of the magmatic rocks have intrusive contacts with the Cabo Formation, although some occurrences are also suggestive of synchronism between volcanism and siliciclastic sedimentation. 40Ar/39Ar and zircon fission tracks for the magmatic rocks indicate an average age of 102 r 1 Ma for the CMP. This age represents an expressive event in the province and is detected in all igneous dated materials. It is considered as a minimum age (Albian) for the magmatic episode and the peak of the rift phase in the PB. The 40Ar/39Ar dates are about 10-14 Ma younger than published palynologic ages for this basin. Geochemically, the CMP may be divided in two major groups; i) a transitional to alkaline suite, constituted by basalts to trachy-andesites (types with fine-grained textures and phenocrysts of sanidine and plagioclase), trachytes (porphyrytic texture, with phenocrysts of sanidine and plagioclase) and monzonites; ii) a alkaline suite, highly fractionated, acidic volcano-plutonic association, formed by four subtypes (pyroclastic flows ignimbrites, fine-to medium-grained rhyolites, a high level granite, and later rhyolites). These four types are distinguished essentially by field aspects and petrographic and textural features. Compatible versus incompatible trace element concentrations and geochemical modeling based on both major and trace elements suggest the evolution through low pressure fractional crystallization for trachytes and other acidic rocks, whereas basalts / trachy-andesites and monzonites evolved by partial melting from a mantle source. Sr and Nd isotopes reveal two distinct sources for the rocks of the CMP. Concerning the acidic ones, the high initial Sr ratios (ISr = 0.7064-1.2295) and the negative HNd (-0.43 to -3.67) indicate a crustal source with mesoproterozoic model ages (TDM from 0.92 to 1.04 Ga). On the other hand, the basic to intermediate rocks have low ISr (0.7031-0.7042) and positive HNd (+1.28 to +1.98), which requires the depleted mantle as the most probable source; their model ages are in the range 0.61-0.66 Ga. However, the light rare earth enrichment of these rocks and partial melting modeling point to an incompatible-enriched lherzolitic mantle with very low quantity of garnet (1-3%). This apparent difference between geochemical and Nd isotopes may be resolved by assuming that the metasomatizing agent did not obliterate the original isotopic characteristics of the magmas. A 2 to 5% partial melting of this mantle at approximately 14 kbar and 1269oC account very well the basalts and trachy-andesites studied. By using these pressure and temperatures estimates for the generation of the basaltic to trachy-andesitic magma, it is determined a lithospheric stretching (E) of 2.5. This E value is an appropriated estimate for the sub-crustal stretching (astenospheric or the base of the lithosphere?) region under the Pernambuco Basin, the crustal stretching probably being lower. The integration of all data obtained in this thesis permits to interpret the magmatic evolution of the PB as follows; 1st) the partial melting of a garnet-bearing lherzolite generates incompatible-enriched basaltic, trachy-andesitic and monzonitic magmas; 2nd) the underplating of these basaltic magmas at the base of the continental crust triggers the partial melting of this crust, and thus originating the acidic magmas; 3rd) concomitantly with the previous stage, trachytic magmas were produced by fractionation from a monzonitic to trachy-andesitic liquid; 4th) the emplacement of the several magmas in superficial (e.g. flows) or sub-superficial (e.g. dykes, sills, domes, laccoliths) depths was almost synchronically, at about 102 r 1 Ma, and usually crosscutting the sedimentary rocks of the Cabo Formation. The presence of garnet in the lherzolitic mantle does not agree with pressures of about 14 kbar for the generation of the basaltic magma, as calculated based on chemical parameters. This can be resolved by admitting the astenospheric uplifting under the rift, which would place deep and hot material (mantle plume?) at sub-crustal depths. The generation of the magmas and their subsequent emplacement would be coupled with the crustal rifting of the PB, the border (NNE-SSW directed) and transfer (NW-SE directed) faults serving as conduits for the magma emplacement. Based on the E parameter and the integration of 40Ar/39Ar and palynologic data it is interpreted a maximum duration of 10-14 Ma for the rift phase (Cabo Formation clastic sedimentation and basic to acidic magmatism) of the PB

Imagens do Brasil nas relações de viagem dos s��culos XVII e XVIII

O presente ensaio toma como objeto de an��lise uma s��rie de descri����es do Rio de Janeiro colonial extra��das de narrativas de viagem escritas por europeus que passaram pela cidade entre os s��culos XVII e XVIII. Para al��m de dar a conhecer a perspectiva que esses visitantes deixaram da urbe e de seus habitantes, seu objetivo �� p��r em discuss��o o papel que os relatos de viagem desempenharam no processo de constru����o da imagem que o europeu da ��poca tinha do brasileiro e, sobretudo, o papel que posteriormente desempenharam no processo de constru����o da imagem que o brasileiro, a partir do s��culo XIX, passou a ter de si pr��prio e do seu pa��s.

Alfabetiza����o no Brasil: conjecturas sobre as relações entre pol��ticas p��blicas e seus sujeitos privados

As complexas e pol��micas quest��es relativas a formula����o, implementa����o e avalia����o de pol��ticas p��blicas para a educa����o no Brasil, nas ��ltimas d��cadas, v��m sendo objeto de importantes estudos e pesquisas. Como resultado, tem-se acumulado significativo corpo de conhecimentos a esse respeito, o que propicia avan��os no debate e possibilita novos estudos e pesquisas a respeito de aspectos cada vez mais espec��ficos da tem��tica. Com o objetivo de contribuir para esse debate, apresentam-se neste artigo conjecturas a respeito da rela����o entre setores p��blicos estatais decorrente especificamente do novo tipo de parceria entre ��rg��os p��blicos do Estado e docentes pesquisadores das universidades p��blicas para formula����o, implementa����o e avalia����o de pol��ticas p��blicas para a alfabetiza����o, iniciada na d��cada de 1980 e enfatizada a partir da d��cada de 1990, com a reforma do Estado brasileiro.

Relações entre condutividade hidr��ulica, transmissividade, condut��ncia longitudinal e s��lidos totais dissolvidos para o aqu��fero livre de Ca��apava do Sul (RS), Brasil

A ��gua subterr��nea �� um importante recurso ao abastecimento p��blico, principalmente para comunidades perif��ricas em grandes cidades ou pequenos munic��pios, onde a instala����o ou prolongamento de sistemas de distribui����o s��o economicamente invi��veis. Estudos voltados �� an��lise da vulnerabilidade de aqu��feros s��o relevantes para subs��dio a pol��ticas p��blicas em saneamento b��sico e preserva����o ambiental. Este estudo contou com o cadastro de 23 po��os rasos localizados no munic��pio de Ca��apava do Sul (RS), onde foram realizadas medidas de resistividade el��trica e cargabilidade por meio de geof��sica, e medidas diretas de condutividade hidr��ulica e s��lidos totais dissolvidos. A an��lise estat��stica dos dados demonstrou diversos graus de correla����o entre par��metros, basicamente condicionados a fatores geol��gicos como porosidade, permeabilidade e s��lidos totais dissolvidos.

Federalismo e relações intergovernamentais no Brasil: a reforma de programas sociais

The article analyses the process of reform in four areas of social policies that affect directly the interests of sub-national governments: basic education, social housing programs, basic sanitation and health. As the study reveals, despite the varying degree of success achieved in the various policy initiatives and contrary to the expectations of the prevailing interpretations of the nature of Brazilian federalism, the federal government faced no insurmountable hurdles in implementing their reform agenda. The study aims at demonstrating that (i) in the absence of any constitutional mandatory requirement, the political autonomy of local governments - typical of federative States - actually enhances the veto power of local governments over policy initiatives proposed by the federal Executive branch. However, (ii) power resources available to the federal Executive branch - such as agenda definition and vetoing powers - in addition to control over resources that are essential to the political survival of the representatives increase the chances of success-of the federal government. Furthermore, (1999), (iii) the constitutional authority of Brazilian states is far more limited than that of the North-American states; (iv) the category federalism, however, is not sufficient to define the potential stability of specific policies, which depends upon how inter-governmental relations are structured in each particular policy. Specifically, (v) constitutional rules, legacies from previous policies and the political cycle frame the decision arenas in various ways, thus conditioning both the strategies and chances of success of the federative players.

As Relações Comerciais do Brasil com os demais BRICs

Incluye bibliograf��a

Macroinvertebrados aqu��ticos associados �� Eichhornia azurea (Swartz) Kunth e suas relações com as vari��veis abi��ticas em ecossistemas l��nticos marginais (S��o Paulo, Brasil)

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Relações entre tempo e evidencialidade nas l��nguas ind��genas do Brasil: um estudo tipol��gico-funcional

P��s-gradua����o em Estudos Lingu��sticos - IBILCE

O setor sucroenerg��tico no Brasil: Estado, hegemonia e relações internacionais - o caso da UNICA no agribusiness internacional

P��s-gradua����o em Ci��ncias Sociais - FFC

Banco Central do Brasil: institucionalidade, relações com o estado e com a sociedade civil, autonomia e controle democr��tico

Incluye Bibliograf��a

Relações Brasil-Estados Unidos

Incluye Bibliograf��a

Trade relations between Brazil and the United States = Relações comerciais entre o Brasil e os Estados Unidos

Includes bibliography

O Brasil e a Guerra do Pac��fico: alian��as estrat��gicas e relações diplom��ticas (1879-1883)

Conselho Nacional de Desenvolvimento Cient��fico e Tecnol��gico (CNPq)

O projeto Teletandem Brasil: as relações entre comunidades virtuais, as comunidades discursivas e as comunidades de pr��tica

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)