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Richard Potts, Anna K Behrensmeyer, J Tyler Faith, Christian A Tryon, Alison S Brooks, John E Yellen, Alan L Deino, Rahab Kinyanjui, Jennifer B Clark, Catherine Haradon, Naomi E Levin, Hanneke J M Meijer, Elizabeth G Veatch, R Bernhart Owen, Robin W Renaut
Development of the African Middle Stone Age (MSA) before 300 thousand years ago (ka) raises the question of how environmental change influenced the evolution of behaviors characteristic of early Homo sapiens We use temporally well-constrained sedimentological and paleoenvironmental data to investigate environmental dynamics before and after the appearance of the early MSA in the Olorgesailie Basin, Kenya. In contrast to the Acheulean archeological record in the same basin, MSA sites are associated with a dramatically different faunal community, more pronounced erosion-deposition cycles, tectonic activity, and enhanced wet-dry variability...
March 15, 2018: Science
Stefano Nuzzo, Brendan Twamley, James A Platts, Robert J Baker
A series of uranyl thiocyanate and selenocyanate of the type [R4 N]3 [UO2 (NCS)5 ] (R4 =n Bu4 , Me3 Bz, Et3 Bz), [Ph4 P][UO2 (NCS)3 (NO3 )] and [R4 N]3 [UO2 (NCSe)5 ] (R4 = Me4 ,n Pr4 , Et3 Bz) have been prepared and structurally characterized. The resulting noncovalent interactions have been examined and compared to other examples in the literature. The nature of these interactions is determined by the cation so that when the alkyl groups are small, chalcogenide···chalcogenide interactions are present, but this "switches off" when R =n Pr and charge assisted U═O···H-C and S(e)···H-C hydrogen bonding remain the dominant interaction...
March 15, 2018: Inorganic Chemistry
Marthe Lefevre, Yann Klinger, Mahmoud Al-Qaryouti, Maryline Le Béon, Khaled Moumani
Temporal distribution of earthquakes is key to seismic hazard assessment. However, for most fault systems shortness of large earthquake catalogues makes this assessment difficult. Its unique long earthquake record makes the Dead Sea fault (DSF) exceptional to test earthquake behaviour models. A paleoseismological trench along the southern section of the DSF, revealed twelve surface-rupturing earthquakes during the last 8000 years, of which many correlate with past earthquakes reported in historical chronicles...
March 14, 2018: Scientific Reports
Masaru Nakano, Takane Hori, Eiichiro Araki, Shuichi Kodaira, Satoshi Ide
Recent studies of slow earthquakes along plate boundaries have shown that tectonic tremor, low-frequency earthquakes, very-low-frequency events (VLFEs), and slow-slip events (SSEs) often accompany each other and appear to share common source faults. However, the source processes of slow events occurring in the shallow part of plate boundaries are not well known because seismic observations have been limited to land-based stations, which offer poor resolution beneath offshore plate boundaries. Here we use data obtained from seafloor observation networks in the Nankai trough, southwest of Japan, to investigate shallow VLFEs in detail...
March 14, 2018: Nature Communications
Indrani Mukherjee, Ross R Large, Ross Corkrey, Leonid V Danyushevsky
The period 1800 to 800 Ma ("Boring Billion") is believed to mark a delay in the evolution of complex life, primarily due to low levels of oxygen in the atmosphere. Earlier studies highlight the remarkably flat C, Cr isotopes and low trace element trends during the so-called stasis, caused by prolonged nutrient, climatic, atmospheric and tectonic stability. In contrast, we suggest a first-order variability of bio-essential trace element availability in the oceans by combining systematic sampling of the Proterozoic rock record with sensitive geochemical analyses of marine pyrite by LA-ICP-MS technique...
March 13, 2018: Scientific Reports
Jin-Min Chen, Nikolay A Poyarkov, Chatmongkon Suwannapoom, Amy Lathrop, Yun-He Wu, Wei-Wei Zhou, Zhi-Yong Yuan, Jie-Qiong Jin, Hong-Man Chen, He-Qun Liu, Truong Quang Nguyen, Sang Ngoc Nguyen, Tang Van Duong, Koshiro Eto, Kanto Nishikawa, Masafumi Matsui, Nikolai L Orlov, Bryan L Stuart, Rafe M Brown, Jodi J L Rowley, Robert W Murphy, Ying-Yong Wang, Jing Che
Southeast Asia and southern China (SEA-SC) harbor a highly diverse and endemic flora and fauna that is under increasing threat. An understanding of the biogeographical history and drivers of this diversity is lacking, especially in some of the most diverse and threatened groups. The Asian leaf-litter frog genus Leptolalax Dubois 1980 is a forest-dependent genus distributed throughout SEA-SC, making it an ideal study group to examine specific biogeographic hypotheses. In addition, the diversity of this genus remains poorly understood, and the phylogenetic relationships among species of Leptolalax and closely related Leptobrachella Smith 1928 remain unclear...
March 9, 2018: Molecular Phylogenetics and Evolution
Steven D Leavitt, Martin Westberg, Matthew P Nelsen, John A Elix, Einar Timdal, Mohammad Sohrabi, Larry L St Clair, Laura Williams, Mats Wedin, H T Lumbsch
Multiple drivers shape the spatial distribution of species, including dispersal capacity, niche incumbency, climate variability, orographic barriers, and plate tectonics. However, biogeographic patterns of fungi commonly do not fit conventional expectations based on studies of animals and plants. Fungi, in general, are known to occur across exceedingly broad, intercontinental distributions, including some important components of biological soil crust communities (BSCs). However, molecular data often reveal unexpected biogeographic patterns in lichenized fungal species that are assumed to have cosmopolitan distributions...
2018: Frontiers in Microbiology
Qiang Qiu, James D P Moore, Sylvain Barbot, Lujia Feng, Emma M Hill
Understanding the rheological properties of the upper mantle is essential to develop a consistent model of mantle dynamics and plate tectonics. However, the spatial distribution and temporal evolution of these properties remain unclear. Here, we infer the rheological properties of the asthenosphere across multiple great megathrust earthquakes between 2004 and 2014 along the Sumatran subduction zone, taking advantage of decade-long continuous GPS and tide-gauge measurements. We observe transient mantle wedge flow following these earthquakes, and infer the temporal evolution of the effective viscosity...
March 8, 2018: Nature Communications
Encarni Montoya, Hayley F Keen, Carmen X Luzuriaga, William D Gosling
Tropical ecosystems play a key role in many aspects of Earth system dynamics currently of global concern, including carbon sequestration and biodiversity. To accurately understand complex tropical systems it is necessary to parameterise key ecological aspects, such as rates of change (RoC), species turnover, dynamism, resilience, or stability. To obtain a long-term (>50 years) perspective on these ecological aspects we must turn to the fossil record. However, compared to temperate zones, collecting continuous sedimentary archives in the lowland tropics is often difficult due to the active landscape processes, with potentially frequent volcanic, tectonic, and/or fluvial events confounding sediment deposition, preservation, and recovery...
2018: Frontiers in Plant Science
Erin M Scott, Mark B Allen, Colin G Macpherson, Ken J W McCaffrey, Jon P Davidson, Christopher Saville, Mihai N Ducea
Climate and tectonics have complex feedback systems which are difficult to resolve and remain controversial. Here we propose a new climate-independent approach to constrain regional Andean surface uplift.87 Sr/86 Sr and143 Nd/144 Nd ratios of Quaternary frontal-arc lavas from the Andean Plateau are distinctly crustal (>0.705 and <0.5125, respectively) compared to non-plateau arc lavas, which we identify as a plateau discriminant. Strong linear correlations exist between smoothed elevation and87 Sr/86 Sr (R2  = 0...
March 6, 2018: Nature Communications
Eoin P McCarney, Chris S Hawes, Jonathan A Kitchen, Kevin Byrne, Wolfgang Schmitt, Thorfinnur Gunnlaugsson
The synthesis of the three-dimensional metal-organic framework material, [Zn7 L6 ]·(H2 NMe2 )4 ·(H2 O)45 (1), derived from a flexible tricarboxylic acid 2,6-bis(1,2,3-triazol-4-yl)pyridine (btp) ligand, is presented. The btp ligand, H3 L, adopts a three-dimensional hydrogen bonding network in the crystalline state through a combination of carboxylic acid dimer and syn-anti-btp/carboxylic acid hydrogen bonding synthons. The Zn(II) species 1 exhibits a three-dimensional framework structure with the rare crs topology and contains linear and undulated solvent channels extending in three dimensions...
March 6, 2018: Inorganic Chemistry
Marcio B DaSilva, Ricardo Pinto-da-Rocha, Juan J Morrone
Based on a cladistic biogeographic analysis of 6 species-level phylogenies of harvestman taxa, we searched for congruence in the historical relationships of 12 areas of endemism of the Brazilian Atlantic Rain Forest. We constructed general area cladograms using Primary Brooks Parsimony Analysis (BPA), BPA of nodes, and paralogy-free subtree analysis. These analyses resulted in 6 general area cladograms, that allow to infer a general pattern of the relationships among areas of endemism from the Brazilian Atlantic Rain Forest...
October 2017: Current Zoology
Rongfeng Ge, Wenbin Zhu, Simon A Wilde, Hailin Wu
Eoarchean [3.6 to 4.0 billion years ago (Ga)] tonalite-trondhjemite-granodiorite (TTG) is the major component of Earth's oldest remnant continental crust, thereby holding the key to understanding how continental crust originated and when plate tectonics started in the early Earth. TTGs are mostly generated by partial melting of hydrated mafic rocks at different depths, but whether this requires subduction remains enigmatic. Recent studies show that most Archean TTGs formed at relatively low pressures (≤1...
February 2018: Science Advances
Kevin Konrad, Anthony A P Koppers, Bernhard Steinberger, Valerie A Finlayson, Jasper G Konter, Matthew G Jackson
Mantle plumes upwelling beneath moving tectonic plates generate age-progressive chains of volcanos (hotspot chains) used to reconstruct plate motion. However, these hotspots appear to move relative to each other, implying that plumes are not laterally fixed. The lack of age constraints on long-lived, coeval hotspot chains hinders attempts to reconstruct plate motion and quantify relative plume motions. Here we provide40 Ar/39 Ar ages for a newly identified long-lived mantle plume, which formed the Rurutu hotspot chain...
February 27, 2018: Nature Communications
Elaine Fiod Costa, Luciano Moreira Pinto, Marcos Adriano Garcia Campos, Thais Mota Gomes, Gyl Eanes Barros Silva
BACKGROUND: Rhinosporidiosis is a rare chronic infection of the mucous membranes caused by the Rhinosporidium seeberi. Approximately 15% of cases of rhinosporidiosis are ocular, occurring mainly in the tarsal conjunctiva. There are only 11 cases of scleral melt with staphyloma formation associated with bulbar conjuctival oculosporidiosis and none of them was associated with partial regression of the scleral ectasia after a corneoscleral tectonic graft. CASE PRESENTATION: a 13-year-old girl with a progressively increasing black mass in the upper nasal part above the cornea of the left eye...
February 27, 2018: BMC Ophthalmology
Jane L Andersen, David L Egholm, Mads F Knudsen, Henriette Linge, John D Jansen, Vivi K Pedersen, Søren B Nielsen, Dmitry Tikhomirov, Jesper Olsen, Derek Fabel, Sheng Xu
Glaciers create some of Earth's steepest topography; yet, many areas that were repeatedly overridden by ice sheets in the last few million years include extensive plateaus. The distinct geomorphic contrast between plateaus and the glacial troughs that dissect them has sustained two long-held hypotheses: first, that ice sheets perform insignificant erosion beyond glacial troughs, and, second, that the plateaus represent ancient pre-glacial landforms bearing information of tectonic and geomorphic history prior to Pliocene-Pleistocene global cooling (~3...
February 26, 2018: Nature Communications
Arthur F Sands, Dmitry A Apanaskevich, Sonja Matthee, Ivan G Horak, Alan Harrison, Shahid Karim, Mohammad K Mohammad, Kosta Y Mumcuoglu, Rupika S Rajakaruna, Maria M Santos-Silva, Joshua Kamani, Conrad A Matthee
No abstract text is available yet for this article.
March 2018: Molecular Phylogenetics and Evolution
Daniel DeMiguel, Lorenzo Rook
Despite its long history of scientific study, the causes underlying the extinction of the insular hominoid Oreopithecus bambolii are still a matter of ongoing debate. While some authors consider intense tectonism and invading species the cause of its extinction ca. 6.7 Ma, others propose climatic change as the main contributing factor. We rely on long-term patterns of tooth wear and hypsodonty of the Baccinello and Fiume Santo herbivore-faunas to reconstruct changes in habitat prior to, during and after the extinction...
March 2018: Journal of Human Evolution
Raffaele Saladino, Lorenzo Botta, Ernesto Di Mauro
Meteorites are consensually considered to be involved in the origin of life on this Planet for several functions and at different levels: (i) as providers of impact energy during their passage through the atmosphere; (ii) as agents of geodynamics, intended both as starters of the Earth's tectonics and as activators of local hydrothermal systems upon their fall; (iii) as sources of organic materials, at varying levels of limited complexity; and (iv) as catalysts. The consensus about the relevance of these functions differs...
February 22, 2018: Life
Yi-Qi Zhang, Mateusz Paszkiewicz, Ping Du, Liding Zhang, Tao Lin, Zhi Chen, Svetlana Klyatskaya, Mario Ruben, Ari P Seitsonen, Johannes V Barth, Florian Klappenberger
Interfacial supramolecular self-assembly represents a powerful tool for constructing regular and quasicrystalline materials. In particular, complex two-dimensional molecular tessellations, such as semi-regular Archimedean tilings with regular polygons, promise unique properties related to their nontrivial structures. However, their formation is challenging, because current methods are largely limited to the direct assembly of precursors, that is, where structure formation relies on molecular interactions without using chemical transformations...
March 2018: Nature Chemistry
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