Icebergs not the trigger for North Atlantic cold events.

Abrupt climate change is a ubiquitous feature of the Late Pleistocene epoch. In particular, the sequence of Dansgaard-Oeschger events (repeated transitions between warm interstadial and cold stadial conditions), as recorded by ice cores in Greenland, are thought to be linked to changes in the mode of overturning circulation in the Atlantic Ocean. Moreover, the observed correspondence between North Atlantic cold events and increased iceberg calving and dispersal from ice sheets surrounding the North Atlantic has inspired many ocean and climate modelling studies that make use of freshwater forcing scenarios to simulate abrupt change across the North Atlantic region and beyond. On the other hand, previous studies identified an apparent lag between North Atlantic cooling events and the appearance of ice-rafted debris over the last glacial cycle, leading to the hypothesis that iceberg discharge may be a consequence of stadial conditions rather than the cause. Here we further establish this relationship and demonstrate a systematic delay between pronounced surface cooling and the arrival of ice-rafted debris at a site southwest of Iceland over the past four glacial cycles, implying that in general icebergs arrived too late to have triggered cooling. Instead we suggest that--on the basis of our comparisons of ice-rafted debris and polar planktonic foraminifera--abrupt transitions to stadial conditions should be considered as a nonlinear response to more gradual cooling across the North Atlantic. Although the freshwater derived from melting icebergs may provide a positive feedback for enhancing and or prolonging stadial conditions, it does not trigger northern stadial events.

Rapid coupling between ice volume and polar temperature over the past 150,000 years.

Current global warming necessitates a detailed understanding of the relationships between climate and global ice volume. Highly resolved and continuous sea-level records are essential for quantifying ice-volume changes. However, an unbiased study of the timing of past ice-volume changes, relative to polar climate change, has so far been impossible because available sea-level records either were dated by using orbital tuning or ice-core timescales, or were discontinuous in time. Here we present an independent dating of a continuous, high-resolution sea-level record in millennial-scale detail throughout the past 150,000 years. We find that the timing of ice-volume fluctuations agrees well with that of variations in Antarctic climate and especially Greenland climate. Amplitudes of ice-volume fluctuations more closely match Antarctic (rather than Greenland) climate changes. Polar climate and ice-volume changes, and their rates of change, are found to covary within centennial response times. Finally, rates of sea-level rise reached at least 1.2 m per century during all major episodes of ice-volume reduction.

Representações Sociais de Doença Mental: Um Estudo Exploratório com Leigos, Profissionais de Saúde e Curandeiros em Maputo / Social Representations of Mental Illness: An Exploratory Study with Lay People, Professionals of Health and Healers in Maputo

What is now referred to by western societies as mental illness, was - and in some way still is ­ understood along the centuries using different interpretations. Associated with each of these interpretations are specifically, an historic moment, and cultural meanings vast and complex. The concentration of public attention in negative episodes of mental illness tends to accentuate the feelings of insecurity on the part of society and contributing to the creation of categories and stereotypes which, in turn, generated the processes of stigmatization and social discrimination of people with experience of mental illness (Jorge-Monteiro, 2006) and are therefore in a vulnerable position. This study aims to understand the social representations of mental illness in Mozambique, particularly in Maputo, of health professionals, lay people and traditional healers. There were twenty-five semi-structured individual interviews, specifically ten healers, nine to laymen and six to health professionals. The technique of content analysis enabled us to identify and organize the explanations related to the concept, the causes, the treatment, evolution, the consequences of mental illness, and intervention proposals perceived as effective for mental illness of each of the above mentioned groups. We reflect on the relations between social representations and practices regarding the perception of mental illness. It was found that the representations of the three groups are formed in a common node shared social; however, there are also some specific differences between the groups - and in the case of the intergroup of laymen, based on the context of provenance. And from these results, reflected also on strategies for reconciling any differences in social representations and practices relating to mental illness.

A doença mental, foi - e de alguma forma ainda é - percebida ao logo dos séculos com recurso a diferentes interpretações. Associados a cada uma destas interpretações encontram-se especificamente, um momento histórico, e significados culturais vastos e complexos. A concentração da atenção pública em episódios negativos da doença mental tende a acentuar os sentimentos de insegurança por parte da sociedade em geral e contribuindo para a criação de categorias e estereótipos que, por sua vez, estão na origem dos processos de estigmatização e de discriminação social da pessoa com experiência de doença mental (Jorge-Monteiro, 2006), estando por isso numa situação de vulnerabilidade. O presente estudo tem como objectivo compreender as representações sociais da doença mental em Maputo (Moçambique), de profissionais de saúde, leigos, e curandeiros. Foram realizadas vinte e cinco entrevistas individuais semi-estruturadas, especificamente dez a curandeiros, nove a leigos e seis a profissionais de saúde. A técnica da análise de conteúdo possibilitou identificar e organizar as explicações ligadas ao conceito, às causas, ao tratamento, à evolução, às consequências da doença mental, e propostas de intervenção percebidas como eficazes para a doença mental, dos três grupos. Reflectimos sobre as relações entre as representações sociais e a percepção das práticas relativas à doença mental. Verificou-se que as representações dos três grupos encontram formadas num nó comum socialmente partilhado, no entanto, existindo também algumas diferenças específicas intergrupos - e no caso dos leigos intragrupo, com base no contexto de proveniência. E a partir destes resultados, reflectiu-se ainda sobre as estratégias de conciliação de eventuais diferenças nas representações sociais e das práticas relativas a doença mental.