272 research outputs found

    The third KV62 radar scan: Searching for hidden chambers adjacent to Tutankhamun's tomb

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    The existence of hidden chambers and corridors adjacent to Tutankhamun’s tomb (code name KV62) hasbeen long debated. In 2015 it was suggested that these chambers may host the as yet undiscovered burialof Nefertiti. In order to test this hypothesis, two Ground Penetrating Radar (GPR) surveys, conductedin 2015 and 2016 from inside KV62, were carried out, but gave contradictory results. To solve theseuncertainties and obtain a more confident and conclusive response, a third GPR survey was conductedby our team in February 2018. The results of this third radar scan are reported in this article. Three GPRsystems with multiple frequency bands (from 150 MHz to 3000 MHz) and very dense spatial samplingwere adopted. After careful data processing, no evidence of marked discontinuities due to the passagefrom natural rock to artificial blocking walls were found in the radargrams. It is therefore concluded thatthere are no hidden chambers immediately adjacent to the Tomb of Tutankhamun

    Evidences for a Late Cretaceous continental arc in the Central Pontides: new insights on alternative geodynamic reconstructions for the Neotethys in Northern Turkey

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    The Intra-Pontide Suture Zone (IPSZ) is the less known one among the suture zones present in Turkey. The IPSZ is well exposed along the Daday-Arac-Kursunlu and Tosya – Emirköy geotraverses where several tectonic units can be recognized. Most of these units are characterized by the occurrence of basic rocks reflecting distinct tectonic origins and geochemical signatures. The study of the basic rocks emerges as an important tool for the geodynamic reconstruction as it can reveal the occurrence of of different types of oceanic basins, the development of a magmatic arc or the presence of rifting-related magmatism. The study of the geotraverses indicates that the imbricate stack of the IPSZ consists of four distinct tectonic units whose successions bear basic rocks: the Aylı Dağ ophiolite Unit, the Arkot Dağ Mèlange and two metamorphic units, referred to as Daday and Devrekani Units. This imbricate stack is probably the result of several episodes of out-of-sequence thrusts that affected the whole IPSZ. The Aylı Dağ Unit includes an about 5 km-thick ophiolite sequence topped by the middle Bathonian to early Callovian radiolarian cherts. In addition, a metamorphic sole is present at the base of the serpentinized peridotites. The geochemical evaluation of pillow-basalts and dykes highlights subduction-related characteristics, similar to IAT- and BABB-type lavas generated above intra-oceanic subduction systems. The Arkot Dağ Mèlange consists of an assemblage of slide-blocks, with different size and lithology, enclosed in a Late Santonian sedimentary matrix. The slide-blocks also include ophiolitic lithologies, mainly represented by basalts, but gabbros and peridotites are also found. The slide-blocks of basalts display affinites to IAT- and BABB-type magmas, signifying the involvement of subduction component, whereas no MORB-like basalt have been found. The Daday unit is characterized by metasedimentary and metabasic rocks deformed under blueschist to subgreenschist metamorphic facies conditions. The metasedimentary rocks include mica-bearing schists, fine-grained marbles and black quartzites. The metabasic lithologies, on the other hand, comprise actinolite-bearing schists and Naamphibole- bearing varieties possibly derived from basaltic and gabbroic protoliths. The metabasic rocks have a wide range of chemical compositions, displaying N-MORB-, E-MORB-, OIB- BABB- and IAT-type signatures. The Devrekani Unit is represented by an assemblage of amphibolites, marbles and micaschists showing a metamorphic climax developed under upper amphibolite facies in the Late Jurassic time. The amphibolites display EMORB-, OIB- BABB- and IAT-type signatures. The geochemical signature of the studied basic rocks provide the evidence that all the basic rocks from the tectonic units of IPSZ are derived by a supra-subduction zone. This finding can provide new nsights for the recostruction of the sgeodynamic history of the Intra-Pontide domain

    Unidad Técnica de Geodesia, Geofísica y Magnetismo de Rocas: Laboratorio de Paleomagnetismo, Magnetismo de Rocas y Modelado Geomagnético

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    Trabajo presentado en la I ReuniĂłn CientĂ­fica del Instituto de Geociencias (CSIC-UCM), los dĂ­as 15 y 16 de septiembre de 2011.Peer reviewe

    Il comprensorio della catacomba di San Callisto tra la via Appia e la via Ardeatina (Roma) alla luce delle indagini geofisiche estensive

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    The paper presents and discusses results from the integration of various methods of geophysical prospection on the plateau between the Via Appia and the Via Ardeatina on the ancient suburb of Rome. The use of large-scale magnetometry, georadar and electromagnetic survey in an area of particularly dense archaeological remains is a highly effective methodology for revealing important information on previously unknown archaeological features. Of particular interest in this case is the comparison between geophysical data and the results of previous excavations, and newly-targeted test investigations that suggest the survival of the documented but previously undiscovered basilica of Pope Damasus as well as unknown catacomb tunnels at San Callisto and elsewhere on the plateau

    Genome analysis and avirulence gene cloning using a high-density RADseq linkage map of the flax rust fungus, Melampsora lini

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    Agroinfiltration of avirulence gene constructs. The response of flax cultivars and near-isogenic lines to expression of avirulence gene candidates (AvrM14-A, AvrM14-B and AvrL2-A) using Agrobacterium tumefaciens-mediated transient transformation. (PDF 2637 kb

    Structures of the flax-rust effector AvrM reveal insights into the molecular basis of plant-cell entry and effector-triggered immunity

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    Fungal and oomycete pathogens cause some of the most devastating diseases in crop plants, and facilitate infection by delivering a large number of effector molecules into the plant cell. AvrM is a secreted effector protein from flax rust (Melampsora lini) that can internalize into plant cells in the absence of the pathogen, binds to phosphoinositides (PIPs), and is recognized directly by the resistance protein M in flax (Linum usitatissimum), resulting in effector-triggered immunity. We determined the crystal structures of two naturally occurring variants of AvrM, AvrM-A and avrM, and both reveal an L-shaped fold consisting of a tandem duplicated four-helix motif, which displays similarity to the WY domain core in oomycete effectors. In the crystals, both AvrM variants form a dimer with an unusual nonglobular shape. Our functional analysis of AvrM reveals that a hydrophobic surface patch conserved between both variants is required for internalization into plant cells, whereas the C-terminal coiled-coil domain mediates interaction with M. AvrM binding to PIPs is dependent on positive surface charges, and mutations that abrogate PIP binding have no significant effect on internalization, suggesting that AvrM binding to PIPs is not essential for transport of AvrM across the plant membrane. The structure of AvrM and the identification of functionally important surface regions advance our understanding of the molecular mechanisms underlying how effectors enter plant cells and how they are detected by the plant immune system
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