696 research outputs found
Clinical-anatomical grounding for pancreatoduodenectomy with preservation of the lesser pancreas
The article presents clinical-anatomical grounding and the first clinical experience of pancreatoduodenectomy with preservation of the lesser pancreas. Implementation of this technique is feasible due to relative anatomical and functional isolation of the lesser pancreas. For the first time in Russia, in the Clinic of Hospital Surgery of Siberian State Medical University pancreatoduodenectomy surgery with preservation of the lesser pancreas was successfully performed in female patient with cancer of the head of pancreas. Pancreatoduodenectomy with preservation of the lesser pancreas enables to augment surgical radicality and to achieve endocrine function of the pancreas at the level requiring relatively low doses of insulin therapy if any. This approach increases the length of life in this category of patients and preserves the quality of life
Tectonic history of the Kolyvan–Tomsk folded zone (KTFZ), Russia : insight from zircon U / Pb geochronology and Nd isotopes
The Kolyvan-Tomsk folded zone (KTFZ) represents part of the Central Asian Orogenic Belt (CAOB). The KTFZ is mainly composed of detrital Late Palaeozoic sedimentary deposits, with minor intrusions. Detrital zircon geochronology on the Upper Devonian to Lower Permian sedimentary sequences of the KTFZ and the associated Gorlovo foreland basin yields four age peaks, reflecting the magmatic events in the source terranes. These events consist of (a) a minor Neoproterozoic peak (0.9-0.7 Ga), (b) a significant Early Palaeozoic peak (550-460 Ma), with a maximum at 500 Ma, and two well-defined Late Palaeozoic peaks during (c) the Middle-Late Devonian (385-360 Ma) and (d) the Carboniferous-Early Permian (360-280 Ma), with a maximum at 320 Ma. Older zircons (>1 Ga) are quite rare in the sampled sedimentary sequences. Slightly negative epsilon Nd values and associated relatively young Nd model ages were obtained (epsilon Nd(T) = -0.78, T (DM) ~1.1 Ga for Upper Devonian sandstones, epsilon Nd(T) = -1.1, T (DM) ~1.1 Ga for Lower Permian sandstones), suggesting only minor contribution of ancient continental crust to the main sedimentary units of the KTFZ. All intrusive and volcaniclastic rocks on the contrary are characterized by high positive epsilon Nd(T) values in the range of 3.78-6.86 and a Late Precambrian model age (T (DM) = 581-916 Ma), which corroborates its juvenile nature and an important depleted mantle component in their source. The oldest unit of the KTFZ, the Bugotak volcanic complex formed at the Givetian-Early Frasnian transition, at about 380 Ma. Upper Devonian detrital deposits of the KTFZ were formed in the Early Palaeozoic accretion belt of the Siberian continent and specifically in a passive continental margin environment. Deposits of the Gorlovo foreland basin, adjoining the KTFZ, were accumulated as a result of erosion of the Carboniferous-Early Permian volcanic rocks, which are now buried under the Meso-Cenozoic sedimentary cover of the West Siberian Basin. The magmatic events, recorded in the KTFZ zircon data, correspond to the most significant magmatic stages that affected the western part of the CAOB as a whole
Search for electron antineutrino interactions with the Borexino Counting Test Facility at Gran Sasso
Electron antineutrino interactions above the inverse beta decay energy of
protons (E_\bar{\nu}_e>1.8) where looked for with the Borexino Counting Test
Facility (CTF). One candidate event survived after rejection of background,
which included muon-induced neutrons and random coincidences. An upper limit on
the solar flux, assumed having the B solar neutrino energy
spectrum, of 1.1 cm~s (90% C.L.) was set with a 7.8
ton year exposure. This upper limit corresponds to a solar neutrino
transition probability, , of 0.02 (90% C.L.).
Predictions for antineutrino detection with Borexino, including geoneutrinos,
are discussed on the basis of background measurements performed with the CTF.Comment: 10 pages, 9 figures, 5 table
Tunka-Rex Virtual Observatory
Tunka-Rex (Tunka Radio Extension) was a detector for ultra-high energy cosmic rays measuring radio emission for air showers in the frequency band of 30-80 MHz, operating in 2010s. It provided an experimental proof that sparse radio arrays can be a cost-effective technique to measure the depth of shower maximum with resolutions competitive to optical detectors. After the decommissioning of Tunka-Rex, as last phase of its lifecycle and following the FAIR (Findability — Accessibility — Interoperability — Reuse) principles, we publish the data and software under free licenses in the frame of the TRVO (Tunka-Rex Virtual Observatory), which is hosted at KIT under the partnership with the KCDC and GRADLCI projects. We present the main features of TRVO, its interface and give an overview of projects, which benefit from its open software and data
Prospects for at CERN in NA62
The NA62 experiment will begin taking data in 2015. Its primary purpose is a
10% measurement of the branching ratio of the ultrarare kaon decay , using the decay in flight of kaons in an unseparated
beam with momentum 75 GeV/c.The detector and analysis technique are described
here.Comment: 8 pages for proceedings of 50 Years of CP
Reconstruction of sub-threshold events of cosmic-ray radio detectors using an autoencoder
Radio detection of air showers produced by ultra-high energy cosmic rays is a cost-effective technique for the next generation of sparse arrays. The performance of this technique strongly depends on the environmental background, which has different constituents, namely anthropogenic radio frequency interferences, synchrotron galactic radiation and others. These components have recognizable features, which can help for background suppression. A powerful method for handling this is the application of convolution neural networks with a specific architecture called autoencoder. By suppressing unwanted signatures, the autoencoder keeps the signal-like ones. We have successfully developed and trained an autoencoder, which is now applied to the data from Tunka-Rex. We show the procedures of the training and optimization of the network including benchmarks of different architectures. Using the autoencoder, we improved the standard analysis of Tunka-Rex in order to lower the threshold of the detection. This enables the reconstructing of sub-threshold events with energies lower than 0.1 EeV with satisfactory angular and energy resolutions
Directional Sensitivity of the NEWSdm Experiment to Cosmic Ray Boosted Dark Matter
We present a study of a directional search for Dark Matter boosted forward
when scattered by cosmic-ray nuclei, using a module of the NEWSdm experiment.
The boosted Dark Matter flux at the edge of the Earth's atmosphere is expected
to be pointing to the Galactic Center, with a flux 15 to 20 times larger than
in the transverse direction.
The module of the NEWSdm experiment consists of a 10 kg stack of Nano Imaging
Trackers, i.e.~newly developed nuclear emulsions with AgBr crystal sizes down
to a few tens of nanometers. The module is installed on an equatorial
telescope. The relatively long recoil tracks induced by boosted Dark Matter,
combined with the nanometric granularity of the emulsion, result in an
extremely low background. This makes an installation at the INFN Gran Sasso
laboratory, both on the surface and underground, viable. A comparison between
the two locations is made. The angular distribution of nuclear recoils induced
by boosted Dark Matter in the emulsion films at the surface laboratory is
expected to show an excess with a factor of 3.5 in the direction of the
Galactic Center. This excess allows for a Dark Matter search with directional
sensitivity. The surface laboratory configuration prevents the deterioration of
the signal in the rock overburden and it emerges as the most powerful approach
for a directional observation of boosted Dark Matter with high sensitivity. We
show that, with this approach, a 10 kg module of the NEWSdm experiment exposed
for one year at the Gran Sasso surface laboratory can probe Dark Matter masses
between 1 keV/c and 1 GeV/c and cross-section values down to
~cm with a directional sensitive search.Comment: 15 pages, 14 figures, updated references, clarified discussion in
intro section. Submitted to JCA
The Borexino detector at the Laboratori Nazionali del Gran Sasso
Borexino, a large volume detector for low energy neutrino spectroscopy, is
currently running underground at the Laboratori Nazionali del Gran Sasso,
Italy. The main goal of the experiment is the real-time measurement of sub MeV
solar neutrinos, and particularly of the mono energetic (862 keV) Be7 electron
capture neutrinos, via neutrino-electron scattering in an ultra-pure liquid
scintillator. This paper is mostly devoted to the description of the detector
structure, the photomultipliers, the electronics, and the trigger and
calibration systems. The real performance of the detector, which always meets,
and sometimes exceeds, design expectations, is also shown. Some important
aspects of the Borexino project, i.e. the fluid handling plants, the
purification techniques and the filling procedures, are not covered in this
paper and are, or will be, published elsewhere (see Introduction and
Bibliography).Comment: 37 pages, 43 figures, to be submitted to NI
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