219 research outputs found
Reduction of vertebrate coprolite diversity associated with the end-Permian extinction event in Vyazniki region, European Russia
© 2016 Elsevier B.V.This study investigates the paleoecological significance of vertebrate coprolites collected from seven sections and three lithofacies of the uppermost Permian and lowermost Triassic succession from the Vyazniki site in the European part of Russia. The analyzed specimens (coprolites and possibly some cololites) were grouped into nine morphotypes (A-I). The coprolite morphotypes were characterized geochemically and compared to the record of other Permian and Triassic coprolites worldwide. Based on the stratigraphic position, shape, structure and composition, all morphotypes were linked to supposed producers. The phosphatic composition of most of the morphotypes and inclusions of arthropod remains, fish scales and bone fragments, suggest that they were produced by carnivores, but non-phosphatic, carbonate-rich, large and oval-shaped coprolites with impressions after plant remains have also been found. The extinction of terrestrial vertebrates around the Permian-Triassic boundary in Russia is interpreted to have occurred within a few thousands of years. Here, we show a pattern of coprolite morphotypes disappearing across this boundary that is consistent with a relatively sudden change in the vertebrate faunal composition across this interval
The first find of Permian ceratodontids (Dipnoi, Osteichthyes) in Russia
© 2015, Pleiades Publishing, Ltd. A huge dipnoan, Permoceratodus gentilis Krupina, gen. et sp. nov. (order Ceratodontiformes), from the terminal Permian beds (Zhukovian Regional Stage, Vyatkian Stage, Upper Permian) of the Sokovka locality (Vladimir Region) is described. It is characterized by the evolutionarily advanced high extent of fusion of skull roof bones and conservative well defined structures of the seismosensory system of the head. This combination distinguishes the new taxon from other Ceratodontiformes. A set of conservative and advanced characters is observed in many vertebrates of the Vyazniki faunal assemblage. Large tetrapods and fishes characterize the terminal developmental stage of the Permian fauna of Eastern Europe, which was followed by impoverishment of the taxonomic composition accompanied by a decrease in body size. The dipnoan described here, like some other vertebrates of this assemblage, belong to high-rank taxa, which had just appeared in the Paleozoic, but reached flourishing in the Mesozoic
Search for anomalies in the {\nu}e appearance from a {\nu}{\mu} beam
We report an updated result from the ICARUS experiment on the search for
{\nu}{\mu} ->{\nu}e anomalies with the CNGS beam, produced at CERN with an
average energy of 20 GeV and travelling 730 km to the Gran Sasso Laboratory.
The present analysis is based on a total sample of 1995 events of CNGS neutrino
interactions, which corresponds to an almost doubled sample with respect to the
previously published result. Four clear {\nu}e events have been visually
identified over the full sample, compared with an expectation of 6.4 +- 0.9
events from conventional sources. The result is compatible with the absence of
additional anomalous contributions. At 90% and 99% confidence levels the limits
to possible oscillated events are 3.7 and 8.3 respectively. The corresponding
limit to oscillation probability becomes consequently 3.4 x 10-3 and 7.6 x 10-3
respectively. The present result confirms, with an improved sensitivity, the
early result already published by the ICARUS collaboration
Precise 3D track reconstruction algorithm for the ICARUS T600 liquid argon time projection chamber detector
Liquid Argon Time Projection Chamber (LAr TPC) detectors offer charged
particle imaging capability with remarkable spatial resolution. Precise event
reconstruction procedures are critical in order to fully exploit the potential
of this technology. In this paper we present a new, general approach of
three-dimensional reconstruction for the LAr TPC with a practical application
to track reconstruction. The efficiency of the method is evaluated on a sample
of simulated tracks. We present also the application of the method to the
analysis of real data tracks collected during the ICARUS T600 detector
operation with the CNGS neutrino beam.Comment: Submitted to Advances in High Energy Physic
Microbiota and food residues including possible evidence of pre-mammalian hair in Upper Permian coprolites from Russia
© 2015 Lethaia Foundation. Published by John Wiley & Sons LtdCoprolites (fossil faeces) provide direct evidence on the diet of its producer and unique insights on ancient food webs and ecosystems. We describe the contents of seven coprolites, collected from the Late Permian Vyazniki site of the European part of Russia. Two coprolite morphotypes (A, B) contain remains of putative bacteria, cyanobacteria, fungi, protists, invertebrate eggs, arthropod elements, undigested bone and tooth fragments, fish scales and elongated hair-like structures with hollow interiors. Content, size and shape of the coprolites together with the associated body fossil record suggest that the most probable scat-producers were carnivorous tetrapods; the bone-rich morphotype A reveals short food retention time and a fast metabolism and is therefore assigned to therapsid carnivores whereas morphotype B with rarer and degraded bones are assigned to archosauromorphs or other non-therapsid carnivores. The general coprolite matrix contains abundant micron-sized spheres and thin-walled vesicles which are interpreted as oxide and phosphatic pseudomorphs after microbial cells. From analyses of the undigested bones, we infer that they represent remains of actinopterygian fish, a therapsid and unrecognizable parts of amphibians and/or reptiles. Additionally, hair-like structures found in one coprolite specimen occur as diagenetically altered (oxide-replaced) structures and moulds (or partly as pseudomorphs) in a microcrystalline carbonate-fluoride-bearing calcium phosphate. This suggests that the latest Permian therapsids probably were equipped with hair-like integument or hairsuit. If true, this is by far the oldest evidence of this mammalian character in the stem group of mammals
Scintillator counters with WLS fiber/MPPC readout for the side muon range detector (SMRD)of the T2K experiment
The T2K neutrino experiment at J-PARC uses a set of near detectors to measure
the properties of an unoscillated neutrino beam and neutrino interaction
cross-sections. One of the sub-detectors of the near-detector complex, the side
muon range detector (SMRD), is described in the paper. The detector is designed
to help measure the neutrino energy spectrum, to identify background and to
calibrate the other detectors. The active elements of the SMRD consist of 0.7
cm thick extruded scintillator slabs inserted into air gaps of the UA1 magnet
yokes. The readout of each scintillator slab is provided through a single WLS
fiber embedded into a serpentine shaped groove. Two Hamamatsu multi-pixel
avalanche photodiodes (MPPC's) are coupled to both ends of the WLS fiber. This
design allows us to achieve a high MIP detection efficiency of greater than
99%. A light yield of 25-50 p.e./MIP, a time resolution of about 1 ns and a
spatial resolution along the slab better than 10 cm were obtained for the SMRD
counters.Comment: 7 pages, 4 figures; talk at TIPP09, March 12-17, Tsukuba, Japan; to
be published in the conference proceeding
A search for the analogue to Cherenkov radiation by high energy neutrinos at superluminal speeds in ICARUS
The OPERA collaboration has claimed evidence of superluminal {\nu}{_\mu}
propagation between CERN and the LNGS. Cohen and Glashow argued that such
neutrinos should lose energy by producing photons and e+e- pairs, through Z0
mediated processes analogous to Cherenkov radiation. In terms of the parameter
delta=(v^2_nu-v^2_c)/v^2_c, the OPERA result implies delta = 5 x 10^-5. For
this value of \delta a very significant deformation of the neutrino energy
spectrum and an abundant production of photons and e+e- pairs should be
observed at LNGS. We present an analysis based on the 2010 and part of the 2011
data sets from the ICARUS experiment, located at Gran Sasso National Laboratory
and using the same neutrino beam from CERN. We find that the rates and
deposited energy distributions of neutrino events in ICARUS agree with the
expectations for an unperturbed spectrum of the CERN neutrino beam. Our results
therefore refute a superluminal interpretation of the OPERA result according to
the Cohen and Glashow prediction for a weak current analog to Cherenkov
radiation. In particular no superluminal Cherenkov like e+e- pair or gamma
emission event has been directly observed inside the fiducial volume of the
"bubble chamber like" ICARUS TPC-LAr detector, setting the much stricter limit
of delta < 2.5 10^-8 at the 90% confidence level, comparable with the one due
to the observations from the SN1987A.Comment: 17 pages, 6 figure
關於關西大學圖書館所藏的抄寫本《新刊監本增注司牧療馬安驥集》
《司牧安驥集》是醫馬書古典著作之一,唐代李石撰的.原書早就遺失,現在能目睹的只有明代增注本.關西大學圖書館所藏的《新刊監本增注司牧療馬安驥集》是抄寫明代弘治17年重刊的.現在《司牧安驥集》系列的版本稀有,明代弘治17年重刊本都有兩種,個個只流傳下一本:南京圖書館藏本與日本市立米澤圖書館藏本.關西大學圖書館所藏本屬於米澤圖書館藏本系列,而且有些部分反映了更早時期的版本,是極其重要的史料.以後通過詳細調查此件抄寫本,可能進行《司牧安驥集》之綜合系統研究而明確此件史料原貌與流傳情況.研究論
Experimental search for the LSND anomaly with the ICARUS detector in the CNGS neutrino beam
We report an early result from the ICARUS experiment on the search for nu_mu
to nu_e signal due to the LSND anomaly. The search was performed with the
ICARUS T600 detector located at the Gran Sasso Laboratory, receiving CNGS
neutrinos from CERN at an average energy of about 20 GeV, after a flight path
of about 730 km. The LSND anomaly would manifest as an excess of nu_e events,
characterized by a fast energy oscillation averaging approximately to
sin^2(1.27 Dm^2_new L/ E_nu) = 1/2. The present analysis is based on 1091
neutrino events, which are about 50% of the ICARUS data collected in 2010-2011.
Two clear nu_e events have been found, compared with the expectation of 3.7 +/-
0.6 events from conventional sources. Within the range of our observations,
this result is compatible with the absence of a LSND anomaly. At 90% and 99%
confidence levels the limits of 3.4 and 7.3 events corresponding to oscillation
probabilities of 5.4 10^-3 and 1.1 10^-2 are set respectively. The result
strongly limits the window of open options for the LSND anomaly to a narrow
region around (Dm^2, sin^2(2 theta))_new = (0.5 eV^2, 0.005), where there is an
overall agreement (90% CL) between the present ICARUS limit, the published
limits of KARMEN and the published positive signals of LSND and MiniBooNE
Collaborations.Comment: 10 pages, 7 figure
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