Protistan Diversity in the Arctic: A Case of Paleoclimate Shaping Modern Biodiversity?

The impact of climate on biodiversity is indisputable. Climate changes over geological time must have significantly influenced the evolution of biodiversity, ultimately leading to its present pattern. Here we consider the paleoclimate data record, inferring that present-day hot and cold environments should contain, respectively, the largest and the smallest diversity of ancestral lineages of microbial eukaryotes.We investigate this hypothesis by analyzing an original dataset of 18S rRNA gene sequences from Western Greenland in the Arctic, and data from the existing literature on 18S rRNA gene diversity in hydrothermal vent, temperate sediments, and anoxic water column communities. Unexpectedly, the community from the cold environment emerged as one of the richest observed to date in protistan species, and most diverse in ancestral lineages.This pattern is consistent with natural selection sweeps on aerobic non-psychrophilic microbial eukaryotes repeatedly caused by low temperatures and global anoxia of snowball Earth conditions. It implies that cold refuges persisted through the periods of greenhouse conditions, which agrees with some, although not all, current views on the extent of the past global cooling and warming events. We therefore identify cold environments as promising targets for microbial discovery

Generative FDG-PET and MRI model of aging and disease progression in Alzheimer's disease.

The failure of current strategies to provide an explanation for controversial findings on the pattern of pathophysiological changes in Alzheimer's Disease (AD) motivates the necessity to develop new integrative approaches based on multi-modal neuroimaging data that captures various aspects of disease pathology. Previous studies using [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) and structural magnetic resonance imaging (sMRI) report controversial results about time-line, spatial extent and magnitude of glucose hypometabolism and atrophy in AD that depend on clinical and demographic characteristics of the studied populations. Here, we provide and validate at a group level a generative anatomical model of glucose hypo-metabolism and atrophy progression in AD based on FDG-PET and sMRI data of 80 patients and 79 healthy controls to describe expected age and symptom severity related changes in AD relative to a baseline provided by healthy aging. We demonstrate a high level of anatomical accuracy for both modalities yielding strongly age- and symptom-severity- dependant glucose hypometabolism in temporal, parietal and precuneal regions and a more extensive network of atrophy in hippocampal, temporal, parietal, occipital and posterior caudate regions. The model suggests greater and more consistent changes in FDG-PET compared to sMRI at earlier and the inversion of this pattern at more advanced AD stages. Our model describes, integrates and predicts characteristic patterns of AD related pathology, uncontaminated by normal age effects, derived from multi-modal data. It further provides an integrative explanation for findings suggesting a dissociation between early- and late-onset AD. The generative model offers a basis for further development of individualized biomarkers allowing accurate early diagnosis and treatment evaluation

O ESPAÇO TERRITORIAL COMO REFERÊNCIA PARA A CONSTRUÇÃO DA CIDADANIA: UMA REFLEXÃO GEOGRÁFICA INTRODUTÓRIA SOBRE O PROBLEMA DAS DEMARCAÇÕES DE TERRAS DE POPULAÇÕES “REMANESCENTES”

Territorially, the Brazilian history is loaded with conflicts and antagonisms. The modernization towards the cities and expansion of the internal market of consumption, national foundations of the new order, conflicts, not a few times, with interests of local collectivities. The deliberate design of the state to achieve new levels of production, with the expansion of production and flow in the territory, has not been accompanied by a similar policy of effective recognition of the different "nations" that formed the national population. More recently, the surface is the discussion on the "remnants", new creations of social emerge where new political subjects. The recognition of these multiple subject presents a reality in which differ widely among themselves. Regarding the territorial quilombola, is the clear differentiation of strong socio-stamp this area both with regard to the origins and ownership of the land, about the events of this (cultural, religious, located in the national territory, the type of housing and size of the community, use of resources, training and recognition in the fight, and so on.). Before this destruction, the rearrangement of productive activities and cultural, produces new relationships that can be considered hybrid. This hybridization, however, follows the logic, it seems, apart from the inclusion.Territorialmente, a história brasileira é carregada de conflitos e antagonismos. A modernização rumo às cidades e a ampliação do mercado interno de consumo, alicerces da nova ordem nacional, conflita, não poucas vezes, com interesses de coletividades locais. O projeto deliberado do Estado de alcançar novos níveis produtivos, com a ampliação da produção e da fluidez dentro do território, não foi acompanhado de uma política semelhante de reconhecimento efetivo dos diferentes “povos” que compunham a população nacional. Mais recentemente, vem a tona a discussão sobre os “remanescentes”, novas criações sociais de onde emergem novos sujeitos políticos. O reconhecimento desses sujeitos apresenta uma realidade múltipla em que diferem bastante entre si. No que se refere à territorialidade quilombola, são nítidas as diferenciações de forte cunho sócio-territorial presente tanto no que diz respeito às origens e posse da terra, quanto às manifestações do presente (culturais, religiosas, de localização no território nacional, do tipo de habitação e tamanho da coletividade, uso dos recursos, estágio na luta e reconhecimento, etc.). Diante desta desestruturação, o rearranjo das atividades produtivas e culturais, produz novas relações que podem ser consideradas híbridas. Esta hibridização, no entanto, obedece a uma lógica, ao que parece, distante da inclusão