Unraveling the forcings controlling the vegetation and climate of the best orbital analogues for the present interglacial in SW Europe

The suitability of MIS 11c and MIS 19c as analogues of our present interglacial and its natural evolution is still debated. Here we examine the regional expression of the Holocene and its orbital analogues over SW Iberia using a model-data comparison approach. Regional tree fraction and climate based on snapshot and transient experiments using the LOVECLIM model are evaluated against the terrestrial-marine profiles from Site U1385 documenting the regional vegetation and climatic changes. The pollen-based reconstructions show a larger forest optimum during the Holocene compared to MIS 11c and MIS 19c, putting into question their analogy in SW Europe. Pollen-based and model results indicate reduced MIS 11c forest cover compared to the Holocene primarily driven by lower winter precipitation, which is critical for Mediterranean forest development. Decreased precipitation was possibly induced by the amplified MIS 11c latitudinal insolation and temperature gradient that shifted the westerlies northwards. In contrast, the reconstructed lower forest optimum at MIS 19c is not reproduced by the simulations probably due to the lack of Eurasian ice sheets and its related feedbacks in the model. Transient experiments with time-varying insolation and CO2 reveal that the SW Iberian forest dynamics over the interglacials are mostly coupled to changes in winter precipitation mainly controlled by precession, CO2 playing a negligible role. Model simulations reproduce the observed persistent vegetation changes at millennial time scales in SW Iberia and the strong forest reductions marking the end of the interglacial "optimum".SFRH/BD/9079/2012, SFRH/BPD/108712/2015, SFRH/BPD/108600/2015info:eu-repo/semantics/publishedVersio

A simple rule to determine which insolation cycles lead to interglacials

The pacing of glacial–interglacial cycles during the Quaternary period (the past 2.6 million years) is attributed to astronomically driven changes in high-latitude insolation. However, it has not been clear how astronomical forcing translates into the observed sequence of interglacials. Here we show that before one million years ago interglacials occurred when the energy related to summer insolation exceeded a simple threshold, about every 41,000 years. Over the past one million years, fewer of these insolation peaks resulted in deglaciation (that is, more insolation peaks were ‘skipped’), implying that the energy threshold for deglaciation had risen, which led to longer glacials. However, as a glacial lengthens, the energy needed for deglaciation decreases. A statistical model that combines these observations correctly predicts every complete deglaciation of the past million years and shows that the sequence of interglacials that has occurred is one of a small set of possibilities. The model accounts for the dominance of obliquity-paced glacial–interglacial cycles early in the Quaternary and for the change in their frequency about one million years ago. We propose that the appearance of larger ice sheets over the past million years was a consequence of an increase in the deglaciation threshold and in the number of skipped insolation peaks.P.C.T. acknowledges funding from a Leverhulme Trust Research Project Grant (RPG-2014-417). M.C. and T.M. acknowledge support from the Belgian Policy Office under contract BR/121/A2/STOCHCLIM. E.W.W. is funded under a Royal Society Research Professorship and M.C. is a senior research scientist with the Belgian National Fund of Scientific Research

Thalidomide in the treatment of erythema nodosum leprosum (ENL): systematic review of clinical trials and prospects of new investigations

FUNDAMENTOS: A hanseníase persiste como problema de saúde pública, e episódios de ENH são eventos agudos que ocorrem antes, durante e após PQT. Na última década, o uso da talidomida como agente imunomodulador foi expandido a outras doenças. OBJETIVOS: realizar revisão sistemática dos ensaios clínicos publicados sobre a eficácia e efeitos colaterais da talidomida no ENH. Descrever metodologia e resultados da triagem para recrutamento de ensaio clínico visando avaliar dose-resposta da talidomida seguida de desmame no ENH moderado e grave, realizado no Brasil. MÉTODOS: Analisaram-se ensaios publicados sobre talidomida no ENH. Foi delineado um ensaio clínico duplo-cego randomizado para avaliar dose de 100 thalid 300mg/dia de talidomida durante fase aguda de ENH, seguida de desmame da talidomida, thalid placebo. Para este ensaio clínico descreve-se metodologia e dados de recrutamento de pacientes, com ênfase na gravidade dos episódios de ENH. RESULTADOS: Os seis ensaios clínicos publicados nas décadas de 1960 e 1970 apontam para o benefício da talidomida no ENH, embora diferenças metodológicas dificultem a comparação. Na fase de recrutamento do ensaio brasileiro, dos 143 pacientes de ENH triados, 65% eram potencialmente elegíveis. A associação com neurite em 56,4% dos ENH moderados e graves exigiu co-intervenção com corticosteróide. CONCLUSÃO: O padrão de recrutamento dos pacientes evidenciou alta freqüência de neurite nos episódios de ENH. O esquema de talidomida isolada no ENH foi avaliado como infreqüente na prática clínica brasileira. O desafio atual é acumular evidências sobre a eficácia e efeitos colaterais da talidomida em associação com corticosteróides.BACKGROUND: Leprosy remains a public health problem. Episodes of erythema nodosum leprosum (ENL) are acute events that occur before, during and after polychemotherapy. In the last decade, the use of thalidomide as an immunomodulating agent was expanded to other diseases. OBJECTIVES: To perform a systematic review of published clinical trials on efficacy and side effects of thalidomide in ENL. To describe the methodology and screening results of recruiting for a clinical trial performed in Brazil, which aimed to assess the dose-response of thalidomide followed by tapering regimen in severe and moderate cases of ENL. METHODS: Published clinical trials on the use of thalidomide in ENL were analyzed. A randomized, double-blind clinical trial was designed to evaluate the doses of 100mg versus 300mg/day thalidomide during the acute stage of ENL, followed by thalidomide tapering regimen versus placebo. For this clinical trial, the methodology and data for enrollment of patients were described, with an emphasis on severity of ENL episodes. RESULTS: Six clinical trials published in the 1960's and 1970's indicated the benefits of thalidomide in ENL, although methodological differences made comparison difficult. In the enrollment stage of the Brazilian trial, 65% of patients were potentially eligible out of 143 ENL patients screened. The association with neuritis in 56.4% of moderate and severe cases of ENL required the co-intervention with steroids. CONCLUSION: The patients' enrollment pattern demonstrated high frequency of neuritis in ENL episodes. The treatment regimen with thalidomide in monotherapy for ENL was considered infrequent in the clinical practice in Brazil. The current challenge is to accumulate evidence about efficacy and side effects of thalidomide in combination with steroids

The topographic evolution of the Tibetan Region as revealed by palaeontology

The Tibetan Plateau was built through a succession of Gondwanan terranes colliding with Asia during the Mesozoic. These accretions produced a complex Paleogene topography of several predominantly east–west trending mountain ranges separated by deep valleys. Despite this piecemeal assembly and resultant complex relief, Tibet has traditionally been thought of as a coherent entity rising as one unit. This has led to the widely used phrase ‘the uplift of the Tibetan Plateau’, which is a false concept borne of simplistic modelling and confounds understanding the complex interactions between topography climate and biodiversity. Here, using the rich palaeontological record of the Tibetan region, we review what is known about the past topography of the Tibetan region using a combination of quantitative isotope and fossil palaeoaltimetric proxies, and present a new synthesis of the orography of Tibet throughout the Paleogene. We show why ‘the uplift of the Tibetan Plateau’ never occurred, and quantify a new pattern of topographic and landscape evolution that contributed to the development of today’s extraordinary Asian biodiversity