Emissions from pre-Hispanic metallurgy in the South American atmosphere

Peer reviewedPublisher PD

Somatic Genomic Variations in Early Human Prenatal Development

Only 25 to 30% of conceptions result in a live birth. There is mounting evidence that the cause for this low fecundity is an extremely high incidence of chromosomal rearrangements occurring in the cleavage stage embryo. In this review, we gather all recent evidence for an extraordinary degree of mosaicisms in early embryogenesis. The presence of the rearrangements seen in the cleavage stage embryos can explain the origins of the placental mosaicisms seen during chorion villi sampling as well as the chromosomal anomalies seen in early miscarriages. Whereas these rearrangements often lead to implantation failure and early miscarriages, natural selection of the fittest cells in the embryo is the likely mechanism leading to healthy fetuses

Arabidopsis hypocotyl adventitious root formation is suppressed by ABA signaling

Roots are composed of different root types and, in the dicotyledonous Arabidopsis, typically consist of a primary root that branches into lateral roots. Adventitious roots emerge from non-root tissue and are formed upon wounding or other types of abiotic stress. Here, we investigated adventitious root (AR) formation in Arabidopsis hypocotyls under conditions of altered abscisic acid (ABA) signaling. Exogenously applied ABA suppressed AR formation at 0.25 µM or higher doses. AR formation was less sensitive to the synthetic ABA analog pyrabactin (PB). However, PB was a more potent inhibitor at concentrations above 1 µM, suggesting that it was more selective in triggering a root inhibition response. Analysis of a series of phosphonamide and phosphonate pyrabactin analogs suggested that adventitious root formation and lateral root branching are differentially regulated by ABA signaling. ABA biosynthesis and signaling mutants affirmed a general inhibitory role of ABA and point to PYL1 and PYL2 as candidate ABA receptors that regulate AR inhibition

Développement d’un insecte artificiel. Nanodrone dédié à la surveillance intra-bâtiment

Dans l’optique de réaliser de la surveillance intra-bâtiment avec un système autonome, mobile, très discret, des recherches sont en cours pour développer des nanodrones. Elles se concentrent sur la compréhension et l’imitation du vol battu des insectes et sur les aspects de la miniaturisation. Cet article décrit la conception et la réalisation d’un insecte artificiel à ailes résonantes à l’aide des technologies de microfabrication de la microélectronique. Un actionneur électromagnétique induit un mouvement de flexion/torsion des ailes correspondant à une cinématique similaire à celle des insectes. L’estimation des phénomènes aéroélastiques en grands déplacements est réalisée à l’aide d’un modèle basé sur les éléments finis et une formulation analytique de l’aérodynamique. Une validation expérimentale est ensuite proposée

Growth and mass wasting of volcanic centers in the northern South Sandwich arc, South Atlantic, revealed by new multibeam mapping

New multibeam (swath) bathymetric sonar data acquired using an EM120 system on the RRS James Clark Ross, supplemented by sub-bottom profiling, reveals the underwater morphology of a not, vert, similar 12,000 km2 area in the northern part of the mainly submarine South Sandwich volcanic arc. The new data extend between 55° 45′S and 57° 20′S and include Protector Shoal and the areas around Zavodovski, Visokoi and the Candlemas islands groups. Each of these areas is a discrete volcanic center. The entirely submarine Protector Shoal area, close to the northern limit of the arc, forms a 55 km long east–west-trending seamount chain that is at least partly of silicic composition. The seamounts are comparable to small subaerial stratovolcanoes in size, with volumes up to 83 km3, indicating that they are the product of multiple eruptions over extended periods. Zavodovski, Visokoi and the Candlemas island group are the summits of three 3–3.5 km high volcanic edifices. The bathymetric data show evidence for relationships between constructional volcanic features, including migrating volcanic centers, structurally controlled constructional ridges, satellite lava flows and domes, and mass wasting of the edifices. Mass wasting takes place mainly by strong erosion at sea level, and dispersal of this material along chutes, probably as turbidity currents and other mass flows that deposit in extensive sediment wave fields. Large scale mass wasting structures include movement of unconsolidated debris in slides, slumps and debris avalanches. Volcanism is migrating westward relative to the underlying plate and major volcanoes are asymmetrical, being steep with abundant recent volcanism on their western flanks, and gently sloping with extinct, eroded volcanic sequences to their east. This is consistent with the calculated rate of subduction erosion of the fore-arc

Vegetation change on mountaintops in northern Sweden: Stable vascular-plant but reordering of lichen and bryophyte communities

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The Distressed Brain: A Group Blind Source Separation Analysis on Tinnitus

Background: Tinnitus, the perception of a sound without an external sound source, can lead to variable amounts of distress. Methodology: In a group of tinnitus patients with variable amounts of tinnitus related distress, as measured by the Tinnitus Questionnaire (TQ), an electroencephalography (EEG) is performed, evaluating the patients ’ resting state electrical brain activity. This resting state electrical activity is compared with a control group and between patients with low (N = 30) and high distress (N = 25). The groups are homogeneous for tinnitus type, tinnitus duration or tinnitus laterality. A group blind source separation (BSS) analysis is performed using a large normative sample (N = 84), generating seven normative components to which high and low tinnitus patients are compared. A correlation analysis of the obtained normative components ’ relative power and distress is performed. Furthermore, the functional connectivity as reflected by lagged phase synchronization is analyzed between the brain areas defined by the components. Finally, a group BSS analysis on the Tinnitus group as a whole is performed. Conclusions: Tinnitus can be characterized by at least four BSS components, two of which are posterior cingulate based, one based on the subgenual anterior cingulate and one based on the parahippocampus. Only the subgenual component correlates with distress. When performed on a normative sample, group BSS reveals that distress is characterized by two anterior cingulate based components. Spectral analysis of these components demonstrates that distress in tinnitus is relate

Hedging against biodiversity loss : forest herbs’ performance in hedgerows across temperate Europe

Questions: How do contrasting environmental conditions among forests and hedgerows affect the vegetative and reproductive performance of understorey forest herbs in both habitats? Can hedgerows support reproductive source populations of forest herbs, thus potentially allowing progressive dispersal of successive generations along these linear habitats? Location: Hedgerows and deciduous forest patches in agricultural landscapes across the European temperate biome. Methods: First, we assessed differences in environmental conditions among forests and hedgerows. Next, we quantified plant performance based on a set of functional life‐history traits for four forest herbs (Anemone nemorosa, Ficaria verna, Geum urbanum, Poa nemoralis) with contrasting flowering phenology and colonisation capacity in paired combinations of forests and hedgerows, and compared these traits among both habitats. Finally, we assessed relationships between plant performance and environmental conditions in both habitats. Results: All study species showed a higher above‐ground biomass in hedgerows than in forests. For Poa nemoralis and Geum urbanum, we also found a higher reproductive output in hedgerows, which was mainly correlated to the higher sub‐canopy temperatures therein. The “ancient forest herb” Anemone nemorosa, however, appeared to have a lower reproductive output in hedgerows than in forests, while for Ficaria verna no reproductive differences were found between the two habitats. Conclusions: This is the first study on such a broad geographical scale to provide evidence of reproductive source populations of forest herbs in hedgerows. Our findings provide key information on strategies by which forest plants grow, reproduce and disperse in hedgerow environments, which is imperative to better understand the dispersal corridor function of these wooded linear structures. Finally, we highlight the urgent need to develop guidelines for preserving, managing and establishing hedgerows in intensive agricultural landscapes, given their potential to contribute to the long‐term conservation and migration of forest herbs in the face of global environmental change