Classe de Ciências

info:eu-repo/semantics/publishedVersio

A influência mediterrânica nas redes sociais do solutrense final peninsular

Esta dissertação apresenta os resultados de um estudo sobre a variabilidade tecnológica das indústrias líticas provenientes de um conjunto de sítios de cronologia solutrense, localizados ao longo da faixa costeira que liga a região do Levante espanhol e a Estremadura portuguesa. Estudos anteriores apontavam para que este se tratasse de um território cultural relativamente alargado, definido pela presença de marcadores simbólicos (pontas de seta e ornamentos), testemunhos de uma identidade étnica comum, que terão sido partilhados através de redes de contacto a longa distância. O objetivo deste estudo foi, precisamente, o de testar o grau de relação entre as várias regiões de modo a poder melhor definir a influência e o modo de funcionamento das redes de contactos. Este objetivo só poderia ser cumprido através da análise dos elementos básicos do sistema adaptativo destas comunidades, neste caso a organização tecnológica. Assim, através da análise de um conjunto alargado de atributos tecnológicos da produção lítica e da sua comparação mediante a utilização de métodos estatísticos multivariados estabeleceram-se uma série de semelhanças e dissemelhanças entre contextos que permitiram constatar que: (1) quando presente, a similitude entre as várias regiões é maioritariamente visível nas dimensões e tipo dos suportes líticos produzidos e, muito raramente, nos atributos tecnológicos específicos da sua produção; (2) algumas destas associações têm uma base cronológica sólida, o que demonstra por um lado, que as indústrias semelhantes do ponto de vista tipológico são contemporâneas e que, por outro, a divisão tradicional do Solutrense de influência mediterrânica não pode ser comprovada com os dados atualmente disponíveis. Do ponto de vista paleoantropológico, os resultados obtidos demonstram que o sistema adaptativo ao Último Máximo Glacial funcionou a duas escalas distintas, mas complementares. Uma que é essencialmente local, formada por nichos eco-culturais bem delimitados, em que as comunidades terão partilhado, e mantido sob a forma de tradições culturais, os esquemas tecno-económicos melhor adaptados às particularidades ecológicas dos respetivos contextos. A outra, suprarregional, que se prende sobretudo com laços sociais a uma escala alargada, através da partilha de conceitos estilísticos nas pontas de projétil, marcadores de uma identidade comum, mantidos também, muito provavelmente, por uma questão adaptativa de resposta ao impacto das mudanças climáticas nas paisagens e abundância/distribuição de recursos.Universidade do Algarve, Faculdade de Ciências Humanas e Sociai

Variación en la explotación de la cuarcita durante el Paleolítico Superior en el Suroeste de la Península Ibérica

The Upper Paleolithic of SW Iberia is marked by the presence of chopper and flake assemblages in quartzite. Detailed characterization at regional and chronological levels of these assemblages is of the utmost importance because, in the most Paleolithic recent phases, they can be found without type-fossils associated or in non-datable deposits. In this study, we used 24 quartzite assemblages from SW Iberia, to test the diagnostic character of this raw material through attribute analysis and refitting. Results indicate that Gravettian, Solutrean and Magdalenian can be distinguished on their quartzite assemblages, enabling, by itself, the differentiation of the Upper Paleolithic key-sequence. They also indicate that Gravettian and Magdalenian assemblages are technologically closer to each other than to Solutrean, a pattern possibly related with the adaptation to the Last Glacial Maximum.El Paleolítico Superior del Suroeste de la Península Ibérica está marcado por la presencia de conjuntos de cantos tallados y lascas en cuarcita. La caracterización detallada a nivel regional y cronológico de estos conjuntos es de la mayor importancia, ya que, en las fases más recientes del Paleolítico, se pueden encontrar sin asociación a fósiles-guía o depósitos datables. En este estudio, hemos utilizado 36 conjuntos de cuarcita de esa región para poner a prueba el carácter diagnóstico de esta materia prima a través de análisis de tributos y remontajes. Los resultados indican que Gravetiense, Solutrense y Magdaleniense se pueden distinguir en sus conjuntos de cuarcita, lo que permite, por sí mismo, la diferenciación de la secuencia clave del Paleolítico Superior. También indican que los conjuntos Gravetiense y Magdaleniense están tecnológicamente más próximos entre sí que respecto al Solutrense, un patrón posiblemente relacionado con la adaptación al Último Máximo Glaciar

Técnicas avançadas no estudo da corrosão

RESUMO: A M.T. Brandão, constituída em 1984, atua no setor tecnológico tendo como principais clientes as indústrias petrolíferas, alimentares e químicas, entre outras empresas industriais e tecnológicas, bem como instituições de ensino e investigação científica, institutos e organismos públicos. Com uma linha completa de produtos e soluções dedicadas à caraterização de materiais, a MT Brandão tem como missão responder às necessidades dos nossos clientes de forma a impulsionar os seus negócios, através da inovação e da melhoria contínua. Esta apresentação pretende assim dar a conhecer os equipamentos que a MT Brandão comercializa que permitem não só o estudo do processo de corrosão como o estudo de revestimentos protetivos e sua caracterização, em particular através de técnicas de Tribocorrosão e Espectroscopia de Raman.info:eu-repo/semantics/publishedVersio

Late Glacial and Early Holocene human demographic responses to climatic and environmental change in Atlantic Iberia

Successive generations of hunter-gatherers of the Late Glacial and Early Holocene in Iberia had to contend with rapidly changing environments and climatic conditions. This constrained their economic resources and capacity for demographic growth. The Atlantic façade of Iberia was occupied throughout these times and witnessed very significant environmental transformations. Archaeology offers a perspective on how past human population ecologies changed in response to this scenario. Archaeological radiocarbon data are used here to reconstruct demographics of the region over the long term. We introduce various quantitative methods that allow us to develop palaeodemographic and spatio-temporal models of population growth and density, and compare our results to independent records of palaeoenvironmental and palaeodietary change, and growth rates derived from skeletal data. Our results demonstrate that late glacial population growth was stifled by the Younger Dryas stadial, but populations grew in size and density during the Early to Middle Holocene transition. This growth was fuelled in part by an increased dependence on marine and estuarine food sources, demonstrating how the environment was linked to demographic change via the resource base, and ultimately the carrying capacity of the environment. This article is part of the theme issue 'Cross-disciplinary approaches to prehistoric demography'.FCT: DL 57/2016/CP1361/CT0026info:eu-repo/semantics/publishedVersio

Vale Boi (Algarve, Portugal) y el Solutrense en el suroeste de la Península Ibérica

Located at the crossroads of two rather different ecological and cultural worlds (Mediterranean Spain and Portuguese Atlantic), the site of Vale Boi (Algarve, Portugal) is a crucial element in understanding the economic and social traits of the communities that inhabited Southwestern Iberia during the Last Glacial Maximum (LGM). Combining an open-air with a rockshelter component, Vale Boi presents a lengthy Solutrean record starting with a Proto-Solutrean phase followed by a set of occupations in the 25 to 20.3 ka cal BP time-span. The very rich and well preserved assemblages proved that the site was treated, throughout, as a seasonal residential camp and although a striking combination of exogenous cultural traits has been identified, regional adaptive idiosyncrasies are quite evident. This paper focuses on the results of the lithics, fauna, beads and portable art analysis from Vale Boi, and their impact on the comprehension of the LGM ecodynamics in Southwestern Iberia.Localizado en el marco de dos contextos diferentes desde el punto de vista ecológico y cultural (el Mediterráneo español y el Atlántico portugués), el yacimiento de Vale Boi (Algarve, Portugal) es un lugar fundamental para comprender la organización económica y social de las comunidades que habitaron el sudoeste de la Península Ibérica durante el Último Máximo Glacial (LGM). Situado en una zona en la que se combinan ocupaciones al aire libre y en abrigo, Vale Boi presenta un amplio registro solutrense que comienza con el Proto-Solutrense y a la que le siguen un amplio número de ocupaciones entre el 25 y el 20,3 ka BP. El importante y bien preservado conjunto demuestra que este asentamiento funcionó como un campamento residencia estacional. Aunque han sido identificados diversos caracteres culturales de origen exógeno, son también evidentes los elementos adaptativos idiosincráticos. El presente artículo se centra en los resultados de los análisis del utillaje lítico, la fauna, las cuentas ornamentales y los objetos de arte mueble de Vale Boi y su impacto en la comprensión ecodinámica del LGM en el sudoeste de la Península Ibérica

No direct evidence for the presence of Nubian Levallois technology and its association with Neanderthals at Shukbah Cave

Blinkhorn et al.present a reanalysis of fossil and lithic material from Garrod’s 1928 excavation at Shukbah Cave, identifying the presence of Nubian Levallois cores and points in direct association with a Neanderthal molar. Te authors argue that this demonstrates the Nubian reduction strategy forms a part of the wider Middle Palaeolithic lithic repertoire, therefore its role as a cultural marker for Homo sapiens population movements is invalid. We raise the following four major concerns: (1) we question the assumptions made by the authors about the integrity and homogeneity of the Layer D assemblage and (2) the implications of this for the association of the Neanderthal tooth with any specifc component of the assemblage, (3) we challenge the authors’ attribution of lithic material to Nubian Levallois technology according to its strict defnition, and (4) we argue that the comparative data presented derive from a biased sample of sites. Tese points critically undermine the article’s conclusion that Shukbah’s Neanderthals made Nubian cores and thus the argument that Neanderthals might have made Nubian technology elsewhere is unsubstantiated.info:eu-repo/semantics/publishedVersio

Portable art and personal ornaments from Txina-Txina: a new later stone age site in the Limpopo River Valley, southern Mozambique

This paper reports on preliminary fieldwork at the Later Stone Age site of Txina-Txina in Mozambique. Excavation yielded a long stratigraphic sequence, a large lithic assemblage, a unique decorated gastropod shell fragment and two ostrich eggshell beadsthe first of their type recovered from a Stone Age context in Mozambique.Fundacao para a Ciencia e Tecnologia [PTDC/EPH-ARQ/4998/2012, PTDC/EPHARQ/4168/2014]; National Geographic Society [W373.15, HJ-033R-17

Adenosine inhibits human astrocyte proliferation independently of adenosine receptor activation

Brain adenosine concentrations can reach micromolar concentrations in stressful situations such as stroke, neurodegenerative diseases or hypoxic regions of brain tumours. Adenosine can act by receptor-independent mechanism by reversing the reaction catalysed by S-adenosylhomocysteine (SAH) hydrolase, leading to SAH accumulation and inhibition of S-adenosylmethionine (SAM)-dependent methyltransferases. Astrocytes are essential in maintaining brain homeostasis but their pathological activation and uncontrolled proliferation plays a role in neurodegeneration and glioma. Adenosine can affect cell proliferation, but the effect of increased adenosine concentration on proliferation of astrocytes is not clarified and was addressed in present work. Human astrocytes (HA) were treated for 3 days with test drugs. Cell proliferation/viability was assessed by the MTT assay and by cell counting. Cell death was evaluated by assessing lactate dehydrogenase (LDH) release and by western blot analysis of αII-Spectrin cleavage. 30µM-Adenosine caused a 40%±3% (p < .05, n = 5) reduction in cell proliferation/viability, an effect reversed by 2U/ml-adenosine deaminase, but unchanged in the presence of antagonists of any of the adenosine receptors. Adenosine alone did not induce cell death. 100µM-Homocysteine alone caused 16%±3% (p < .05) decrease in HA proliferation. Combined action of adenosine and homocysteine decreased HA proliferation by 76%±4%, an effect higher (p < .05) than the sum of the effect of adenosine and homocysteine alone (56%±5%). The inhibitory effect of adenosine on HA proliferation/viability was mimicked by two adenosine kinase inhibitors and attenuated in the presence of folate (100µM) or SAM (50-100µM). The results suggest that adenosine reduces HA proliferation by a receptor-independent mechanism probably involving reversal of SAH hydrolase-catalysed reaction.info:eu-repo/semantics/acceptedVersio

The early Aurignacian dispersal of modern humans into westernmost Eurasia

Documenting the first appearance of modern humans in a given region is key to understanding the dispersal process and the replacement or assimilation of indigenous human populations such as the Neanderthals. The Iberian Peninsula was the last refuge of Neanderthal populations as modern humans advanced across Eurasia. Here we present evidence of an early Aurignacian occupation at Lapa do Picareiro in central Portugal. Diagnostic artifacts were found in a sealed stratigraphic layer dated 41.1 to 38.1 ka cal BP, documenting a modern human presence on the western margin of Iberia ∼5,000 years earlier than previously known. The data indicate a rapid modern human dispersal across southern Europe, reaching the westernmost edge where Neanderthals were thought to persist. The results support the notion of a mosaic process of modern human dispersal and replacement of indigenous Neanderthal populations.BCS-1420299 / BCS-1724997 / BCS-1420453 / BCS-1725015 / SGS-2020-017 / DL 57/2016/CP1361/CT0026 / IF/01075/2013info:eu-repo/semantics/publishedVersio