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Sensitive areas, like those of the upwelling systems, which are responsible for high ecological diversity, fisheries resources and air-sea CO2 exchanges are threatened by climate warming, and therefore, it is crucial to understand how they behaved in past warm climates. The Iberian margin upwelling system corresponds to the northern branch of the Canary Eastern Boundary Upwelling System. At the present, seasonal upwelling of cold and nutrient-rich waters makes the margin highly productive, being responsible for the high ecological biodiversity richness in the area. Despite of its enormous ecological and social importance, the knowledge on how the upwelling system worked in the past is still limited, particularly for periods older than 900 ka. In this work, we focused on the reconstruction of surface water conditions during the Late Pliocene, a period characterized by warm temperatures and high atmospheric CO2 concentration and considered as a unique analogue for future climate conditions. We studied sediments from IODP Site U1391 (37°21.5′N; 9°24.6′W, 1085 m water depth), recovered at the Southwest Iberian margin during Expedition 339, which provided for the first time, an almost continuous marine record of the SW Iberian margin dating back to the Pliocene. Surface water conditions have been reconstructed using planktonic foraminifer faunas and lipid biomarker concentrations across Marine Isotope Stages (MIS) G12 to G3 (2.84 to 2.66 Ma). The planktonic foraminifer results are being compared to the alkenone derived sea-surface temperature (SST), and the total alkenone concentration (reflecting coccolithophore productivity) records of Site U1391 in order to get a comprehensive interpretation of changes in sea surface productivity, seasonality and ecological diversity.

A systematic investigation of the spatial and temporal variability in coccolithophore abundance and distribution through the water column of the NW Iberian coastal up-welling system was performed. From July 2011 to June 2012, monthly sampling at various water depths was conducted at two parallel stations located at 42 degrees N. Total coccosphere abundance was higher at the outer-shelf station, where warmer, nutrient-depleted waters favoured coccolithophore rather than phytoplanktonic diatom blooms, which are known to dominate the inner-shelf location. In seasonal terms, higher coccosphere and coccolith abundances were registered at both stations during upwelling seasons, coinciding with high irradiance levels. This was typically in conjunction with stratified, nutrient-poor conditions (i.e. relaxing upwelling conditions). However, it also occurred during some upwelling events of colder, nutrient-rich subsurface waters onto the continental shelf. Minimum abundances were generally found during downwelling periods, with unexpectedly high coccolith abundance registered in subsurface waters at the inner-shelf station. This finding can only be explained if strong storms during these downwelling periods favoured resuspension processes, thus remobilizing deposited coccoliths from surface sediments, and hence hampering the identification of autochthonous coccolithophore community structure. At both locations, the major coccolithophore assemblages were dominated by Emiliania huxleyi, small Gephyrocapsa group, Gephyrocapsa oceanica, Florisphaera profunda, Syracosphaera spp., Coronosphaera mediterranea, and Calcidiscus leptoporus. Ecological preferences of the different taxa were assessed by exploring the relationships between environmental conditions and temporal and vertical variability in coccosphere abundance. These findings provide relevant information for the use of fossil coccolith assemblages in marine sediment records, in order to infer past environmental conditions, of particular importance for Paleoceanography. Both E. huxleyi and the small Gephyrocapsa group are proposed as proxies for the upwelling regime with a distinct affinity for different stages of the upwelling event: E. huxleyi was associated with warmer, nutrient-poor and more stable water column (i.e. upwelling relaxation stage) while the small Gephyrocapsa group was linked to colder waters and higher nutrient availability (i.e. early stages of the upwelling event), similarly to G. oceanica. Conversely, F. profunda is suggested as a proxy for the downwelling regime and low-productivity conditions. The assemblage composed by Syracosphaera pulchra, Coronosphaera mediterranea, and Rhabdosphaera clavigera may be a useful indicator of the presence of subtropical waters conveyed northward by the Iberian Poleward Current. Finally, C. leptoporus is proposed as an indicator of warmer, saltier, and oligotrophic waters during the downwelling/winter regime. EXCAPA project - Xunta de Galicia [10MDS402013PR]; CALIBERIA project (Fundacao para a Ciencia e a Tecnologia - Portugal) [PTDC/MAR/102045/2008]; CALIBERIA project [COMPETE/FEDER-FCOMP-01-0124-FEDER-010599, BI/PTDC/MAR/102045/2008/2010-016, BI/PTDC/MAR/102045/2008/2010-022, BI/PTDC/MAR/102045/2008/2011-027]; Ministerio de Economia y Competitividad [CGL2015-68459-P]; Ministry of Education of Spain [AP2010-2559]; ETH Zurich Postdoctoral Fellowship from the Swiss Federal Institute of Technology in Zurich (ETHZ); Xunta de Galicia (Spain); FCT [SFRH/BPD/111433/2015]; Plurianual/Estrategico project [UID/Multi/04326/2013] info:eu-repo/semantics/publishedVersion

A violência no ambiente familiar é um dos motivos mais citados por crianças e adolescentes em situação de rua para justificar o abandono do lar. O presente estudo visa a investigar como as crianças e adolescentes nesta condição percebem suas famílias. Foram entrevistadas 50 crianças e adolescentes, 27 nas instituições e 23 nas ruas. Apesar das diferenças nas percepções entre institucionalizados e entrevistados nas ruas, os dados revelam que a maioria apresenta sentimentos de afeto e aceitação alternados com indicações de maus tratos e rejeição dos familiares. Desta forma, os resultados sugerem que diferentes significados de família são construídos por estas crianças e adolescentes durante o processo de desenvolvimento. Pode-se constatar oscilações na forma de conceber uma família pensada - ou idealizada, referencial, corpo de regras - e a vivida - a que se desvela na realidade do cotidiano, principalmente no caso das crianças e adolescentes que vivem nas instituições. Home violence is one of the reasons most frequently mentioned by street children to justify home abandonment. The present research aims to investigate how children under this condition perceive their families. Fifty children from two groups were interviewed: twenty-seven were in the institutions and twenty-three in the streets. Although the perceptions of the two groups of children were different, the results showed that most of them expressed affection and acceptance shifted with maltreatment and rejection toward their families. Therefore, the results suggest that these children along the developmental process construct different meanings of family. There are clear evidences of the oscillation in their conceptions of a thought family - idealized, referential, setting of social norms - and a lived family - the one that comes up in everyday life, mainly in the case of children who live in the institutions.

[1] Diatom assemblages document surface hydrographic changes over the Bermuda Rise. Between 19.2 and 14.5 ka, subtropical diatom species and Chaetoceros resting spores dominate the flora, as in North Atlantic productive regions today. From 16.9 to 14.6 ka, brackish and fresh water diatoms are common and their contribution is generally coupled with total diatom abundance. This same interval also contains rare grains of ice-rafted debris. Coupling between those proxies suggests that successive discharge of icebergs might have stimulated productivity during Heinrich event 1 (H1). Iceberg migration to the subtropics likely created an isolated environment involving turbulent mixing, upwelled water, and nutrient-rich meltwater, supporting diatom productivity in an otherwise oligotrophic setting. In addition, the occurrence of mode water eddies likely brought silica-rich waters of Southern Ocean origin to the euphotic zone. The persistence of lower-salinity surface water beyond the last ice rafting suggests continued injection of fresh water by cold-core rings and advection around the subtropical gyre. These results indicate that opal productivity may have biased estimates of meridional overturning based on 231Pa/230Th ratios in Bermuda Rise sediments during H1.

Polis : Revista de Estudos Jurídico-Políticos. - ISSN 0872-8208. - N. 13-16 (2007). - p. 257-299.

Home violence is one of the reasons most frequently mentioned by street children to justify home abandonment. The present research aims to investigate how children under this condition perceive their families. Fifty children from two groups were interviewed: twenty-seven were in the institutions and twenty-three in the streets. Although the perceptions of the two groups of children were different, the results showed that most of them expressed affection and acceptance shifted with maltreatment and rejection toward their families. Therefore, the results suggest that these children along the developmental process construct different meanings of family. There are clear evidences of the oscillation in their conceptions of a thought family - idealized, referential, setting of social norms - and a lived family - the one that comes up in everyday life, mainly in the case of children who live in the institutions. A violência no ambiente familiar é um dos motivos mais citados por crianças e adolescentes em situação de rua para justificar o abandono do lar. O presente estudo visa a investigar como as crianças e adolescentes nesta condição percebem suas famílias. Foram entrevistadas 50 crianças e adolescentes, 27 nas instituições e 23 nas ruas. Apesar das diferenças nas percepções entre institucionalizados e entrevistados nas ruas, os dados revelam que a maioria apresenta sentimentos de afeto e aceitação alternados com indicações de maus tratos e rejeição dos familiares. Desta forma, os resultados sugerem que diferentes significados de família são construídos por estas crianças e adolescentes durante o processo de desenvolvimento. Pode-se constatar oscilações na forma de conceber uma família pensada - ou idealizada, referencial, corpo de regras - e a vivida - a que se desvela na realidade do cotidiano, principalmente no caso das crianças e adolescentes que vivem nas instituições.

Heinrich event 1 (H1) is a climate event resulting from the release into the North Atlantic of a huge volume of sea ice and icebergs from the northern hemisphere ice sheets. We present here high-resolution diatom records from the Bermuda Rise (Sargasso Sea) and the Laurentian Fan (South of Newfoundland) to assess its impacts on North Atlantic surface circulation and its timing. The event is composed of three phases: the two first correspond to major pulses of Ice Rafted Debris (IRD) and the third phase relates to its immediate aftermath. At both sites, diatom abundances start to rise at 16.8 ka. This increase is marked by diatom species thriving in cold environments over the Laurentian Fan, while brackish and fresh water diatom species characterize this increase over the Bermuda Rise. This last record implies icebergs migration to subtropical latitudes and nutrient-rich meltwater to support such diatom productivity. During the second phase of the event, both sites record maximum diatom abundances, when sea ice conditions are dominant over the Laurentian Fan and the contribution of brackish-fresh water diatoms culminates over the Bermuda Rise. The persistence of lower salinity related diatom species over the Bermuda Rise suggests a continuous injection of cold fresh water by cold-core rings, as observed nowadays. The last phase witnesses the persistence of low salinity water over the Laurentian Fan, while a decrease towards the disappearance of diatoms in the sediment occurs over the Bermuda Rise. Regarding the relationship between IRD and diatom abundance, it appears that a critical amount of icebergs is necessary to stimulate diatom productivity. The disturbances induced by H1 appear to end ~14.6 ka over the Bermuda Rise, while over the Laurentian Fan, the high diatom production persists until 14.1 ka and the salinity anomaly until 13.8 ka.

Mestrado em Geoquímica Ambiental Este trabalho com o título: Variações climáticas e inputs terrigenos no Prodelta do Tejo durante os últimos 13.5ky, insere-se no projecto de investigação Paleoceanografia e Ambiente em desenvolvimento no DGM do IGM, tem como principal objectivo a condução da investigação cientifica necessária à documentação das mudanças globais, regionais e locais inscritas nos sedimentos da margem continental Portuguesa, com vista a um melhor conhecimento da paleoceanografia do Oceano Atlântico, e contribuir para avaliar as alterações devidas a fenómenos naturais e à actividade humana. É neste contexto que surge. Para a concretização dos objectivos propostos, realizou-se: a) A caracterização de sedimentos depositados na Plataforma Continental adjacente ao rio Tejo, no que respeita à abundância relativa de n-alcanos, n-alcoois e alcanonas; b) A avaliação do input terrigeno provenientes do Tejo a partir da análise de n-alcanos e n-alcanois; c) A determinação da Temperatura da Superfície dos Oceanos (SST) utilizando as alcanonas como indicador. em duas sequencias sedimentares (cores) (D13882 e D13902), recolhidos durante a campanha Discovery 249 em 2000 e um boxcore PO286-26-1B recolhido durante a campanha PALEO 1 em Maio de 2002. Foram analisadas 152 amostras de sedimentos marinhos (56 amostras do core D13902; 63 do core D13882 e 33 amostras do boxcore PO287-26-1B) segundo os procedimentos de análise do Laboratório de Química Ambiental do Consejo Superior de Investigaciones Cientificas (ICER – CSIC- Barcelona). Para além destes procedimentos foi também realizada a análise granulométrica e elementar CHNS, segundo os procedimentos do Laboratório de Geologia Marinha – IGM, neste caso a 598 amostras do Core D13902, 33 amostras do boxcore PO287-26-1B e a 56 amostras do core D13882. Os três cores analisados constituem uma sequência sedimentar que regista os últimos 13,5cal. ka Age. BP. Os resultados obtidos demonstram uma elevada concentração de n-alcanos e n-alcanois, face à concentração de alcanonas o que indica uma componente terrigena importante e o rio como principal fonte de material depositado na área. Os registos de n-alcanos e de n-alcoois revelam a mesma distribuição indicando uma boa preservação de matéria orgânica ao longo de toda a sequência sedimentar. Os registros de temperatura de superfície do oceano (SST) revelam máximos na ordem de 19ºC e mínimos de 8ºC. Durante o Holocénico a SST varia entre os 15 e os 19 ºC exibindo os valores mínimos durante o evento conhecido como Pequena Idade do Gelo (Little Ice Age – LIA) (período entre 1300 a 1800 anos AD). As temperaturas mínimas (8ºC e 9ºC) foram registadas durante Younger Dryas, evento centrado há aproximadamente 12 ka BP. Estes intervalos de baixa temperatura são marcados por um aumento na concentração total de alcanonas e em carbono orgânico, o que reflecte um aumento da produtividade. As amostras utilizadas para identificação e contagem de cocolitóforos dão indicação de um domínio do género Gephyrocapsid no qual se destacam a espécie G. oceânica e um grupo de “Small” Gephyrocapsid como responsáveis pela produção de alcanonas na área. A presença da alcanona tetrainsaturada (C37:4) associada a mínimos de temperatura poderá estar relacionado com as entradas de água doce reflectindo as alterações na influência das águas vindas do rio Tejo. Sea surface temperatures and river input have been reconstructed from long chain alkenones and n-alkanes respectively, for a 13,5kyr sedimentary sequence recovered from the Portuguese Margin on the Tagus prodelta (38ºN, 9ºW; PO287-26-1B; D13902; D13882). The age model has been constructed from five 14C AMS 1 data and a correlation to core SU8118. The surface sediment was dated by 210Pb. In the upper part of this sequence (2001 cal. Age to 11,5ky BP) temperatures ranged between 15ºC and 19ºC, exhibiting the lowest values during the Little Ice Age. This low temperature interval is marked by a general increase in organic carbon and total alkenones concentration pointing to increased productivity. Minima sea surface temperature occured during the Younger Dryas (8ºC) This minima corresponded to an increase in the proportion of the tetra unsaturated alkenone (%C37:4), possibly reflecting the influence of less saline waters originated from iceberg melting, as proposed by Bard et al. (Nature 2000). N-alkanes and n-alcohols show a parallel downcore trend indicating a common origin for terrigenous material and very good preservation of organic matter throughout the sequence. In addition, the paralleslim of these two molecular markers with C37 alkenones suggest that river input was the main source of nutrients to the area and the responsible factor for increased coccolithophore production during the last 13,5 ky cal. Age BP. In terms of coccolith assemblages, G. oceanica and other small gephyrocapsid, were the dominant species.