Repositório RCAAP

The global or planetary reach of gentrification has become a mainstream in critical urban studies. And yet, the ‘travels’ of a concept originated in specific places and times have often brought about a loss of explanatory and strategic power. In this article, we argue that another concept, that of articulation developed by Laclau and Mouffe, is particularly adequate to help gentrification, touristification and financialisation to travel among places and levels of abstraction. In order to make this argument, we focus on Southern Europe, whose cities had long been considered scarcely gentrifiable and where, more recently, critical urban scholarship has made large use ogf gentrification, touristification and financialisation to explain the impacts of crisis, austerity, and afterwards economic rebound driven by real estate and tourism. We explore in multi-scalar perspective the trajectory of Mouraria, a historical neighbourhood in Lisbon – and particularly the dimensions of housing and local politics. We show how Mouraria, during the last decade, shifted from being a ‘deviant’ case – capable of taking advantage of neoliberal regeneration policies in order to keep its social diversity and most of its long-term residents – toward one ‘paradigmatic’ of urbanisation-as-accumulation and contentious urban politics. We explain this shift by focusing on its multi-scalar determinants; concluding that present urban change in many Southern European cities should be understood as the articulation of various processes, which include gentrification, touristification and financialisation.

When do presidents delegate policy-making authority to their foreign ministries? And is foreign policy unique in this respect? We posit that six international, national, and personal factors determine the opportunity and motivation of presidents to delegate, and then analyse the cases of Argentina, Brazil, and Mexico in 1946–2015. By applying fuzzy-set qualitative comparative analysis, we find that four combinations of factors are sufficient paths to delegation: (1) international stability and elite consensus on foreign policy; (2) international stability, right-wing president, and low diplomatic professionalisation; (3) international stability, right-wing president, and low presidential expertise on foreign policy; or (4) absence of authoritarianism combined with elite consensus on foreign policy and right-wing president. Our study of foreign ministries reinforces some of the main findings of the scholarly literature on other ministries, thus challenging the view of foreign policy-making as different from domestic policy areas.

A forma de produção, distribuição e consumo de notícias tem atravessado sérias mudanças ao longo dos últimos anos, suscitadas, entre outros fatores, pela introdução de tecnologias digitais na esfera da comunicação social. Este capítulo pretende contribuir para o debate em torno desta questão, centrando- se nas implicações deste processo na condição social dos jornalistas. Partindo da análise de anúncios de emprego, os objetivos são compreender o tipo da empresa requerente; as principais características da oferta de trabalho (o meio de comunicação ou a área temática, a título de exemplo); as condições oferecidas (contratuais, salariais, etc.); e o perfil do jornalista solicitado (qualificações e competências).

Os estudos desenvolvidos nos capítulos anteriores procuram contribuir para dar resposta às questões de fundo da investigação que organiza este livro: como está o jornalismo a ser afetado pelo processo de hegemonia digital dos media e como considerá-lo neste quadro como entidade cultural das sociedades democráticas? Que instituições, normas, processos e atores têm vindo a produzir-se no jornalismo e na informação e que fatores estão a formá-los? De que modo é que as novas instituições de media, com as suas estruturas de recursos, prescrições e atores, estão a moldar as expectativas e práticas de produtores e consumidores de media? Como abordar o jornalismo português na sua relação com o processo em curso de hegemonia digital? O objetivo é concorrer para o entendimento refl exivo das consequências da viragem digital e neoliberal nos media e no jornalismo.

Os processos de globalização e digitalização têm interpelado, desafi ado e modifi cado o lugar e o entendimento de cultura no jornalismo, as lógicas de produção e receção de informação e as fontes de reputação profi ssional. O estudo destas alterações ganha relevância também pela centralidade dos intermediários culturais nos projetos editoriais, proporcionando a compreensão da complexidade do trabalho cultural na economia do conhecimento, cada vez mais uma economia digital baseada em freelancing (Capelli e Keller, 2013). O estudo da Artecapital, a partir de análise documental e na realização de entrevistas1, demonstra, com as suas especifi cidades, as viragens que o processo de digitalização tem suscitado na organização do jornalismo cultural e da crítica de artes. O texto caracteriza a revista eletrónica, publicada desde 2006, em quatro partes: a primeira incide na génese do projeto editorial; a segunda foca a sua estrutura organizativa; a terceira analisa o formato editorial; a quarta centra-se nos produtores dos textos. A conclusão sistematiza o que mais confere signifi cado à Artecapital, avançando-se uma síntese inicial. Viabilizada pela economia de custos do suporte digital, a revista inspira-se nos géneros jornalísticos convencionais, desenvolve possibilidades das novas tecnologias, como a curadoria informacional. Orientada por uma equipa minimal, a plataforma suporta a sua longevidade num conjunto constantemente renovado de colaboradores, que entregam e expõem a escrita e a reflexão sobre arte e cultura em nome da autoexpressão e procura de visibilidade.

O objectivo da Newsletter do Instituto de Saúde Baseado na Evidência (ISBE) é a disponibilização de informação sobre áreas relevantes para a prática clínica, baseada na melhor evidência científica. São localizados estudos relevantes e de alta qualidade, criticamente avaliados pela sua validade, importância dos resultados e aplicabilidade prática e resumidos numa óptica de suporte à decisão clínica. É dada prioridade aos estudos de causalidade – revisões sistemáticas, ensaios clínicos, estudos de coorte prospectivos/retrospectivos, estudos seccionais cruzados e caso‐controlo – incluindo‐se ainda, quando justificado, estudos qualitativos considerados de elevada qualidade metodológica e importância clínica.

Background: Myriads of signaling pathways in a single cell function to achieve the highest spatio-temporal integration. Data are accumulating on the role of electromechanical soliton-like waves in signal transduction processes. Theoretical studies strongly suggest feasibility of both classical and quantum computing involving microtubules. Aim: A theoretical study of the role of the complex composed of the plasma membrane and the microtubule-based cytoskeleton as a system that transmits, stores and processes information. Methods: Theoretical analysis presented here refers to (i) the Penrose–Hameroff theory of consciousness (Orchestrated Objective Reduction; Orch OR), (ii) the description of the centrosome as a reference system for construction of the 3D map of the cell proposed by Regolini, (iii) the Heimburg–Jackson model of the nerve pulse propagation along axons’ lipid bilayer as soliton-like electro-mechanical waves. Results and conclusion: The ideas presented in this paper provide a qualitative model for the decision-making processes in a living cell undergoing a differentiation process. Outlook: This paper paves the way for the real-time live-cell observation of information processing by microtubule-based cytoskeleton and cell fate decision making.

In general, reactive nitrogen species, like nitric oxide (NO) and peroxynitrite are classified in primary and secondary according its benefic or deleterious effects respectively. Multiple benefic roles through the body has been attributed to nitric oxide (NO), a key signaling molecule, which acts as vasodilator relaxing smooth muscles of arteries; participates in the blood pressure control; hinders the initiation of inflammation NO liberated from endothelium cells or lymphocytes to intravascular corporal fluid enter into erythrocytes through membrane band 3 protein being after captured by deoxyhemoglobin or by oxyhemoglobin. Inside the erythrocytes several chemical reactions occur with generation of S-nitrosoglutathione a NO reservoir molecules and NO derivatives (NOx) molecules namely nitrite, nitrate and peroxynitrite. The erythrocyte acts as sensor of the tissues oxygen partial pressure and consequently change its oxygen levels lead along with NO contents. NO is released through band 3 protein into the blood, at microcirculatory network, in tissues with low oxygen partial pressure. The aim of this mini review was to present the erythrocyte signal transduction pathways associated with NO and S-nitrosoglutathione efflux, metabolic behavior of the NO reservoir molecules and NO reactive species in human erythrocytes under several biological conditions. For examples, the effects of external amphipathic molecules, fibrinogen, and internal manipulation of protein phosphorylation degree and redox status on erythrocyte. NOx, NO and S-nitrosoglutathione efflux levels are herein included. Erythrocyte NO efflux evidenced as biomarkers of inflammatory vascular diseases will be herein highlighted.

A major challenge for humankind is to reduce global carbon dioxide (CO2) emissions to avoid the most harmful impacts of climate change. The transport sector is responsible for almost 1/4 of the world’s energy-related emissions, with road transportation representing around 1/5 of the fuel consumption. Electric vehicles (EVs) may help to reduce CO2 emissions, but their diffusion is uncertain due to market barriers. This paper investigates the electric vehicle (EV), which has a smaller ecological footprint, as an alternative capable of meeting the needs of personal transport in Brazil. To carry out this evaluation, the study considers socio-techno-economic and political-environmental-innovation aspects to assess the challenges and opportunities facing the adoption of electric vehicles. The analysis was carried out based on a survey administered to a wide range of stakeholders. A SWOT analysis was performed to understand the most critical factors affecting the future of EVs in Brazil, which is a top-ten automotive manufacturer worldwide and a leader in sugar cane ethanol production. The results suggest light-duty electric vehicles (LDEV) as a first option for low-carbon passengers’ mobility and that EVs expansion will require market regulation, incentive policies and adequate charging infrastructure. Both consumers and society in general will benefit most from the expansion of EVs due to low emissions and total cost of ownership (TCO). The results show where decision-makers should focus their attention.

Purpose: We hypothesize that patients with type 1 diabetes (T1D) may have abnormal retinal vascular responses before diabetic retinopathy (DR) is clinically evident. Optical coherence tomography angiography (OCTA) was used to dynamically assess the retinal microvasculature of diabetic patients with no clinically visible retinopathy. Methods: Controlled nonrandomized interventional study. The studied population included 48 eyes of 24 T1D patients and 24 demographically similar healthy volunteers. A commercial OCTA device (AngioVue) was used, and two tests were applied: (1) the hypoxia challenge test (HCT) and (2) the handgrip test to induce a vasodilatory or vasoconstrictive response, respectively. The HCT is a standardized test that creates a mild hypoxic environment equivalent to a flight cabin. The handgrip test (i.e., isometric exercise) induces a sympathetic autonomic response. Changes in the parafoveal superficial and deep capillary plexuses in both tests were compared in each group. Systemic cardiovascular responses were also comparatively evaluated. Results: In the control cohort, the vessel density of the median parafoveal superficial and deep plexuses increased during hypoxia (F1,23 = 15.69, P < 0.001 and F1,23 = 16.26, P < 0.001, respectively). In the T1D group, this physiological response was not observed in either the superficial or the deep retinal plexuses. Isometric exercise elicited a significant decrease in vessel density in both superficial and deep plexuses in the control group (F1,23 = 27.37, P < 0.0001 and F1,23 = 27.90, P < 0.0001, respectively). In the T1D group, this response was noted only in the deep plexus (F1,23 = 11.04, P < 0.01). Conclusions: Our work suggests there is an early impairment of the physiological retinal vascular response in patients with T1D without clinical diabetic retinopathy.

Introduction: Optical coherence tomography angiography (OCT-A) is a novel diagnostic tool with increasing applications in ophthalmology clinics that provides non-invasive high-resolution imaging of the retinal microvasculature. Our aim is to report in detail an experimental protocol for analyzing both vasodilatory and vasoconstriction retinal vascular responses with the available OCT-A technology. Methods: A commercial OCT-A device was used (AngioVue®, Optovue, CA, United States), and all examinations were performed by an experienced technician using the standard protocol for macular examination. Two standardized tests were applied: (i) the hypoxia challenge test (HCT) and (ii) the handgrip test, in order to induce a vasodilatory and vasoconstriction response, respectively. OCT-A was performed at baseline conditions and during the stress test. Macular parafoveal vessel density of the superficial and deep plexuses was assessed from the en face angiograms. Statistical analysis was performed using STATA v14.1 and p < 0.05 was considered for statistical significance. Results: Twenty-four eyes of 24 healthy subjects (10 male) were studied. Mean age was 31.8 ± 8.2 years (range, 18–57 years). Mean parafoveal vessel density in the superficial plexus increased from 54.7 ± 2.6 in baseline conditions to 56.0 ± 2.0 in hypoxia (p < 0.01). Mean parafoveal vessel density in the deep plexuses also increased, from 60.4 ± 2.2 at baseline to 61.5 ± 2.1 during hypoxia (p < 0.01). The OCT-A during the handgrip test revealed a decrease in vessel density in both superficial (55.5 ± 2.6 to 53.7 ± 2.9, p < 0.001) and deep (60.2 ± 1.8 to 56.7 ± 2.8, p < 0.001) parafoveal plexuses. Discussion: In this work, we detail a simple, non-invasive, safe, and non-costly protocol to assess a central nervous system vascular response (i.e., the retinal circulation) using OCT-A technology. A vasodilatory response and a vasoconstriction response were observed in two physiologic conditions—mild hypoxia and isometric exercise, respectively. This protocol constitutes a new way of studying retinal vascular changes that may be applied in health and disease of multiple medical fields.

The article by Cekirdekci and Bugan published in this issue of the Journal opens up new prospects for improving our knowledge of microvascular angina (MVA). Clinical characterization of MVA and coronary artery disease (CAD) shows them to be examples of endothelial dysfunction at the level of the microcirculation and macrocirculation, respectively. There is now general consensus about both coronary microcirculation and macrocirculation. The authors selected biomarkers of hemorheology and inflammation and applied clinical methodology to diagnose and classify the patients and the control group. The latter were similar to the MVA and CAD patient groups regarding the presence of other associated diseases. The statistical computation performed confirmed the value of the control group used, which in my opinion is more realistic than other control groups selected without comorbidities.

Understanding Disaster Risk: A Multidimensional Approach presents the first principle from the UNISDR Sendai Framework for Disaster Risk Reduction, 2015-2030. The framework includes a discussion of risk and resilience from both a theoretical and governance perspective in light of ideas that are shaping our common future. In addition, it presents innovative tools and best practices in reducing risk and building resilience. Combining the applications of social, financial, technological, design, engineering and nature-based approaches, the volume addresses rising global priorities and focuses on strengthening the global understanding of vulnerability, displaced communities, cultural heritages and cultural identity. Readers will gain a multifaceted understanding of disaster, addressing both historic and contemporary issues. Focusing on the various dimensions of disaster risk, the book details natural and social components of risk and the challenges posed to risk assessment models under the climate change paradigm.

Riverine floods are responsible for significant human and material losses. Climate change scenarios pose additional challenges to flood susceptibility and risk assessment (Kundzewicz et al., 2014; Winsemius et al., 2015). While in recent decades the increases in global flood damage have mainly been driven by population and economic activity growth in flood-prone areas, climate change projections launch a high level of uncertainty about future impacts, showing, however, that flood protection standards can play a relevant part in mitigating such effects (Winsemius et al., 2015) [...]

In contemporary societies the media is oriented to cover disaster considering the intersection between three dimensions of risk: hazard, exposure and vulnerability. In the past, the prevailing theory was the naturalization of disasters that considered disasters as extreme events generated by the nature, where human action did not influence disaster occurrences and consequences. In view of the predominant theory of the nature of disasters, the objective of this work is to analyze the approach of journalism on disasters in the early 20th century. This research explores a catalogue of hydro-geomorphological events selected from the Disaster database for the period 1865–1909, which were reported by the Portuguese newspaper Diário de Notícias (DN). News analysis was guided by the News Protocol. The news set highlighted the naturalization of disasters, the focus on post-disaster consequences and local correspondents as the main source reporting disaster occurrences in the territory.

Plant sterols have been reported to decrease plasma concentrations of cholesterol without any side effects. To evaluate the effects on plasma cholesterol concentrations and the hemorheological parameters, we performed a study with hypercholesterolemic patients (n=19) treated with phytosterol-enriched milk (2 g/day). Hypercholesterolemic patients (n=15) of matched age drinking equal type of milk but without phytosterols were used as control group. Concentrations of total cholesterol, HDL-C, LDL-C and hemorheological parameters were measured in the beginning, after 15 and 30 days of milk intake. After 15 days of beverage intake, hypercholesterolemic subjects treated with phytosterol-enriched milk showed a significant decrease in plasma concentrations of total cholesterol and LDL-C by 9.62% (p<0.05) and 12.20% (p<0.05), respectively. After 30 days, a little increase in the total cholesterol and LDL-C concentrations were observed. In the hypercholesterolemic control group there were nonsignificant changes between plasma concentrations of total cholesterol, HDL-C and LDL-C during the study. The evaluation of plasma viscosity and erythrocyte aggregation shows no changes statistically significant during the study for both groups studied. The results obtained during the study show a positive effect with the phytosterol-enriched milk as plasma cholesterol-lowering as combined treatment for hypercholesterolemia.

The consumption of plant sterols has been shown to decrease plasma concentrations of cholesterol without adverse effects in human subjects. To evaluate if milk would be a good vehicle for phytosterols to lower plasma levels of cholesterol, we performed a randomized blind study with healthy subjects (n = 22) and hypercholesterolemic patients (n = 19), both groups treated with phytosterol-enriched milk (2 g/d). Another hypercholesterolemic group (n = 15) was used as a control group. Lipid profile and biochemical, hematologic, and hemorheological parameters were determined at the beginning and after 15 and 30 days of milk beverage intake. After 15 days of treatment, healthy individuals showed lowered total cholesterol and LDL-C levels, by 8.31% (P = .05) and 11% (P < .05), respectively. After 30 days of the trial, these values did not change significantly. Hypercholesterolemic patients treated with phytosterol-enriched milk demonstrated significantly diminished levels of total cholesterol and LDL-C concentrations, by 9.62% (P < .05) and 12.20 % (P < .05), respectively. After 30 days, an increase in the total cholesterol and LDL-C levels was observed for hypercholesterolemic subjects, 6.69% (P < .05) and 8.68% (P < .05), respectively. In the hypercholesterolemic control subjects, no difference was found between plasma levels of total cholesterol, high-density lipoprotein cholesterol, and LDL-C. Only healthy subjects showed significant changes during the intake of phytosterol-enriched milk. The results obtained indicate that phytosterol-enriched milk is a good vehicle for reducing plasma cholesterol in hypercholesterolemic subjects.

The interactions between membrane, peripheral and cytoskeleton proteins are responsible for the maintenance of erythrocyte deformability (EEI) and some of these interactions are modulated by PKC activity. Protein band 3 of the erythrocyte membrane is phosphorylated by phosphotyrosine kinases (PTK) and dephosphorylated by phosphotyrosine phosphatase (PTP). It was previously described by us a signal transduction mechanism that describes a possible pathway connecting an erythrocyte external membrane protein, acetylcholinesterase (AChE), with protein band 3. So how does PKC activity modulate EEI when protein band 3 is phosphorylated or dephosphorylated in absence or presence of AChE effectors? To answer this we used phorbol 12-myristate 13-acetate (PMA) as an activator and chelerythrine chloride as inhibitor of PKC and also band 3 modulators of band 3 phosphorylation degree, in presence and absence of AChE effectors in order to measure in whole blood samples EEI. Our results showed that erythrocyte deformability was significantly (i) decreased by inhibition of PKC, in absence and presence of AChE inhibitor velnacrine (ii) increased with PMA in absence and presence of ACh and (iii) decreased in presence of calpeptin in absence and presence of either chelerythrine or PMA. These results establish dependence between cytoskeleton proteins, PKC activity, band 3 phosphorylation degrees and EEI. Better understanding of those proteins interactions on transduction mechanisms might trigger possible targets for drug action that would modulate EEI.

Os complexos alcalino-carbonatíticos correspondem a produtos de magmas mantélicos gerados e instalados durante os eventos de reactivação tectono-magmática (rifting intracontinental) de terrenos antigos, predominantemente de idade Arcaica ou Proterozóica. As rochas carbonatíticas são rochas ígneas ricas com mais de 50% em volume de minerais carbonatados magmáticos, contendo menos de 10% de sílica. No território de Angola conhecem-se 45 complexos alcalino-carbonatíticos, os quais correspondem a estruturas (sub)intrusivas com morfologia (sub)circular que se distribuem ao longo de dois alinhamentos tectónicos intra-continentais activos desde o Cretácico Inferior (138-130 Ma). O Complexo Carbonatítico de Bailundo (CCB) situa-se a 11 km a NE da localidade de Bailundo e a cerca de 100 km a NNE da cidade de Huambo, numa região denominada Mungo. Apresenta uma morfologia típica de estrutura anelar com ≈ 7 km de diâmetro e ≈ 38.5 km2 de área. Desenvolve-se na Província Alcalino-Carbonatítica Diagonal Trans-angolana, definida ao longo de um alinhamento SW-NE desde o litoral até à fronteira com a República Democrática do Congo. O CCB compreende um domínio central, correspondendo ao Morro Belém (atingindo 1805 m de altitude), constituído por rochas carbonatíticas (ferro-carbonatitos e cálcio-carbonatitos) e um anel externo de fenitização. O tema desta tese tem como objectivo primordial o estudo dos Elementos de Terras Raras (ETR), nomeadamente: (i) sua abundância relativa; (ii) caracterização e distribuição espacial; (iii) fases minerais que as incorporam e seu modo de ocorrência e (iv) avaliação do potencial económico. Um último objectivo prende-se com a avaliação das características petrogenéticas do CCB, com base na análise dos ETR e elementos traço. Os ETR, também designados por lantanídeos, compreendem os 15 metais do grupo IIIA da Tabela Periódica com número atómico 57 ao 71; a estes associam-se ítrio (Y), escândio (Sc) e tório (Th). As suas aplicações em diversas soluções tecnológicas, levam ao contínuo aumento da procura. Neste contexto, o estudo dos complexos carbonatíticos é muito importante, pois contêm frequentemente, para além de outros elementos, concentrações anómalas em ETR. Em termos gerais, os fenitos e carbonatitos examinados revelam textura e natureza composicional relativamente heterogénea que reflecte a sobreposição de transformações desencadeadas por processos tardi-magmáticos e hidrotermais subsequentemente intensificados pela meteorização química. Estes processos revelam-se cruciais ao desenvolvimento de associações minerais singulares; tal é o caso dos minerais portadores de ETR como flúor-carbonatos (parisite), fosfatos (rabdofanite e apatite) e óxidos (pirocloro e cerianite). Estas fases minerais, em conjunto com outras descritas em trabalhos anteriores (e.g. Santos, 2010), portadoras de metais de interesse, tornam o CCB um complexo polimetálico Fe-Nb-ETR (Ba) com potencial económico significativo. A avaliação do potencial económico em [ETR+Y+Sc] (= REO*) revela conteúdos medianos elementares mais elevados para os ferro-carbonatitos com 0.81 wt% (x= 1.26 wt%), seguido dos cálcio-carbonatitos com 0.64 wt% (x= 1.16 wt%) e fenitos com 0.33 wt% (x= 0.75 wt%); as anomalias em ETR desenvolvem-se nomeadamente sector central e SW dos ferro-carbonatitos e nas faixas de transição para os cálcio-carbonatitos. Os minerais do grupo do pirocloro (pirocloro e Ba-pirocloro) ocorrem em todas as litologias, excepto o Ba-pirocloro que apenas se encontra nas rochas carbonatíticas; apresentam-se sob a forma de cristais euédricos de granularidade grosseira, disseminados pela matriz e apresentando quantidades traço em ETR (≤ 7.78 wt%), mas elevados conteúdos em Nb (67.57 wt% - ferro-carbonatitos; 69.57 wt% - cálcio-carbonatitos; 64.95 wt% - fenitos) e Ba (19.16 - ferro-carbonatitos e 14.1 wt% - cálcio-carbonatitos). A cerianite ocorre nos ferro-carbonatitos sob a forma de grãos de dimensão muito reduzida disseminados pela matriz e com conteúdos em ETR de 64.4 wt% (essencialmente Ce com 56.3 wt%); os minerais do grupo da rabdofanite [brockite, rabdofanite-(Ce), rabdofanite-(Nd)] são encontrados nos exemplares dos ferro-carbonatitos e formam disseminações matriciais tardias, bem como preenchimentos de redes anastomosadas de veios, filonetes e venulações, apresentando conteúdos em ETR2O3 variáveis entre 21.2 e 61.2 wt%; a parisite presente nos cálcio-carbonatitos ocorre em agregados de grão fino e morfologia radial e fibrosa, disseminados na matriz e desenvolvendo intercrescimentos com outros flúor-carbonatos (e.g. bastnäsite, synchysite) cuja identificação fidedigna não foi possível; apresenta conteúdos medianos em ETR2O3 de 44.8 wt%. A apatite, assim como o pirocloro, apresenta conteúdos traço em ETR (≤ 1.13 wt%) e ocorre em exemplares dos cálcio-carbonatitos e fenitos em secções prismáticas e basais, constituindo por vezes agregados monominerálicos. São observadas três tipologias de mineralização: (i) mineralizações primárias tipificadas pela fase pirocloro, (ii) magmático-hidrotermais tipificadas pelo desenvolvimento de Ba-pirocloro, parisite e apatite e (iii) supergénicas (hidrotermais?) tipificadas pelo desenvolvimento de cerianite e rabdofanite. Os padrões de concentração em ETR e multi-elementares normalizados relativamente ao condrito e manto primitivo, respectivamente, afiguram-se compatíveis com a distribuição e abundância das fases minerais portadoras em ETR. Mostram elevados conteúdos em ETR tipificados por forte enriquecimento em ETRL relativamente a ETRP, onde o La e o Ce constituem os ETRL mais abundantes. De salientar os enriquecimentos em BaO e SrO; os empobrecimentos bem marcados em Rb, K, Zr-Hf e Ti e a fraccionação Nb/Ta (em média 14016 e 3521.97 para os ferro-carbonatitos e cálcio-carbonatitos, respectivamente) e Zr/Hf (em média 36.97 e 59.02 para os ferro-carbonatitos e cálcio-carbonatitos, respectivamente), com valores superiores ao manto primitivo (Nb/Ta = 17 e Zr/Hf = 36; Sun & McDonough, 1989), congruentes com o metassomatismo carbonatítico. Sublinha-se a elevada fraccionação Nb/Ta atribuída à fraccionação do pirocloro. O exame comparativo da assinatura petrogenética do CCB com as informações publicadas para os complexos carbonatíticos de Angola e Brasil torna-se importante, na medida em que permite caracterizar a província carbonatítica de Angola e definir (potencialmente) guias para a prospecção e pesquisa mineral. A análise realizada confirma a potencialidade de Bailundo em ETR relativamente a alguns complexos carbonatíticos angolanos (Sulima-Monte Verde, Logonjo, Tchivira-Bonga e Lupongola) e brasileiros (Juquiá e Jacupiranga). Virulundo (complexo carbonatíticos angolano) e Itapirapuã, Angico dos Dias e Araxá (complexos carbonatíticos brasileiros) mostraram conteúdos em ETR próximos e, por vezes, superiores (e.g. Araxá e Virulundo) aos obtidos para Bailundo. A distribuição de concentração em ETR normalizados relativamente ao condrito para os complexos angolanos e brasileiros revela, tal como para Bailundo, forte enriquecimento em ETR, nomeadamente ETRL. Os padrões de concentração em elementos incompatíveis revelam assinaturas geoquímicas semelhantes às obtidas para Bailundo, destancando-se diferenças nos valores de BaO e SrO, mais elevadas para Bailundo que nos restantes complexos (angolanos e brasileiros), com excepção de Araxá que apresenta valores de SrO mais elevados. A elevada fraccionação Nb/Ta apenas se observa para os carbonatitos angolanos, incluindo Bailundo (excepto Tchivira-Bonga), e para o carbonatito brasileiro de Araxá.

We assessed the redox thiol status influence on nitric oxide (NO) metabolism and efflux in erythrocytes stimulated with acetylcholinesterase substrate (acetylcholine, ACh) and inhibitor (velnacrine maleate, VM). Erythrocyte suspensions from healthy donors were incubated with increasing concentrations of dithiothreitol (1-50microM), in the presence and absence of acetylcholine/velnacrine (10microM). Levels of NO, nitrite/nitrate, S-nitrosohemoglobin, peroxynitrite and S-nitrosoglutathione were determined by spectrofluorimetric and spectrophotometric methods. Dithiothreitol significantly mobilized NO toward nitrite/nitrate and S-nitrosoglutathione, and decreased the amount of NO efflux. Both ACh/VM induce changes on the levels of erythrocyte nitrite/nitrate dependent on the DTT concentration. Higher levels of peroxynitrite and S-nitrosoglutathione were seen with velnacrine in presence of DTT 1 and 50microM. We concluded that dithiothreitol-induced activation of erythrocyte thiol status decreases NO efflux and allows greater intracellular NO mobilization onto different derivative molecules, both in the absence and presence of acetylcholinesterase substrate and inhibitor.