The status of the Baikal-GVD neutrino telescope under construction and its main scientific results are presented. The detector consists of 2916 optical sensors located at 81 vertical strings deep ...below the surface of Lake Baikal. Its geometric configuration is optimized for detecting neutrinos with energies above 100 TeV. Events from muon neutrinos were identified, the flux of which is consistent with the expectation for the flux of atmospheric neutrinos. The data obtained during the alerts of the ANTARES and IceCube telescopes were analyzed. Candidate events for high-energy neutrinos of astrophysical origin have been obtained.
Abstract
The high-energy muon neutrino events of the IceCube telescope, that are triggered as neutrino alerts in one of two probability ranks of astrophysical origin, “gold” and “bronze”, have been ...followed up by the Baikal-GVD in a fast quasi-online mode since September 2020. Search for correlations between alerts and GVD events reconstructed in two modes, muon-track and cascades (electromagnetic or hadronic showers), for the time windows ±1 h and ±12 h does not indicate statistically significant excess of the measured events over the expected number of background events. Upper limits on the neutrino fluence will be presented for each alert.
Abstract
Baikal-GVD (Gigaton Volume Detector) is a neutrino telescope located in pure water of Lake Baikal. At the current stage (season 2021), detector is composed of 2304 optical modules arranged ...in 8 clusters. In searching for neutrino cascade events, light patterns produced via discrete stochastic energy losses along muon tracks create the most abundant background. Methods to separate cascade-like events from tracks and neutrino cascades in a single cluster have been developed and optimized. One of the method tries to find the maximum number of track hits amongst cascade hits, which are present in the muon bundle event. Other ones rely on the distributions of charges and positions of hits on optical modules associated with cascade events. All suppression methods were optimized by the Monte Carlo simulation datasets.
Abstract
The Baikal-GVD is a neutrino telescope situated in the deepest freshwater lake in the world — Lake Baikal. The design of the Baikal-GVD trigger system allows also to study the ambient light ...of the lake. The analysis of the optical light activity of Baikal water, particularly, time and spatial variations of the luminescence activity for data collected in years 2018, 2019, and 2020 is presented. For the first time we observed highly luminescent layer moving upwards with maximal speed of 28 m/day in January 2021.
Abstract
The Large-scale deep underwater Cherenkov neutrino telescopes like Baikal-GVD, ANTARES or KM3NeT, require calibration and testing methods of their optical modules. These methods usually ...include laser-based systems which allow us to check the telescope responses to the light and for real-time monitoring of the optical parameters of water such as absorption and scattering lengths, which show seasonal changes in natural reservoirs of water. We will present a testing method of a laser calibration system and a set of dedicated tools developed for Baikal-GVD, which includes a specially designed and built, compact, portable, and reconfigurable scanning station. This station is adapted to perform fast quality tests of the underwater laser sets just before their deployment in the telescope structure, even on ice, without a darkroom. The testing procedure includes the energy stability test of the laser device, 3D scan of the light emission from the diffuser and attenuation test of the optical elements of the laser calibration system. The test bench consists primarily of an automatic mechanical scanner with a movable Si detector, beam splitter with a reference Si detector and, optionally, Q-switched diode-pumped solid-state laser used for laboratory scans of the diffusers. The presented test bench enables a 3D scan of the light emission from diffusers, which are designed to obtain the isotropic distribution of photons around the point of emission. The results of the measurement can be easily shown on a 3D plot immediately after the test and may be also implemented to a dedicated program simulating photons propagation in water, which allows us to check the quality of the diffuser in the scale of the Baikal-GVD telescope geometry.
Time synchronization system of Baikal-GVD Allakhverdyan, V.A.; Avrorin, A.D.; Avrorin, A.V. ...
Journal of instrumentation,
09/2021, Letnik:
16, Številka:
9
Journal Article
Recenzirano
The Baikal-GVD neutrino telescope currently consists of 8 clusters of 288 optical modules (photodetectors). One cluster comprises 8 strings, each of which is subdivided into 3 sections of 12 optical ...modules. This paper presents the methods of time synchronization between the different GVD components (optical modules, sections, clusters) and estimations of time synchronization accuracy.
Abstract
The first stage of the construction of the Baikal-GVD deep underwater neutrino telescope is planned to be completed in 2024. For the second stage of the detector deployment, a data ...acquisition system based on fiber-optic technologies has been proposed, which will allow for increased data throughput and more flexible trigger conditions. A dedicated test facility has been built and deployed at the Baikal-GVD site to test the new technological solutions. We present the principles of operation and results of tests of the new data acquisition system.
Aim. Summarize and analyze information on the results of studies on the antagonistic properties of Bacillus bacteria against phytopathogenic fungi of the genus Fusarium.Materials and Methods. Current ...information of research by Russian and foreign scientists on the role of bacteria of the genus Bacillus to suppress Fusarium diseases of plants and contamination of plant products with mycotoxins was studied and critically analysed.Results. Information on the prospects for the use of bacteria‐antagonists of phytopathogenic fungi of the genus Bacillus for plant protection against diseases caused by toxinogenic fungi of the genus Fusarium has been generalized. The role of lipopeptides produced by bacteria in inhibiting the growth of fungi, which manifests itself both through the destruction of the cell wall of the fungus and by increasing the immune status of the plant, has been shown. The study contains information on the structure and mechanism of action of the main anti‐fungal cyclic lipopetides. The features of the manifestation of the antagonistic properties of Bacillus bacteria, which consist in the ability of bacterial metabolites to destroy mycotoxins which can help to reduce their toxicity, have been disclosed. The prospect of searching for bacterial strains of the genus Bacillus suitable for creating effective biofungicides against Fusarium fungi is substantiated.Conclusion. Knowledge of the mechanisms of action of bacteria of the genus Bacillus as antagonists of Fusarium fungi will contribute to the careful selection of strains that are promising for the development of effective biological products for replacing chemical fungicides with biofungicides in the control of F. graminearum and its mycotoxins, which will make it possible to obtain products that are not burdened with either chemical means of protection or mycotoxins which are dangerous for consumers.
Aim
– to study the biocontrol properties of
B. velezensis
BZR 336g and
B. velezensis
BZR 517 strains against Fusarium pathogens using the fungus
Fusarium graminearum
as an example and to reduce the ...accumulation of deoxynivalenol (DON) and zearalenone (ZEN)
in vitro
.
Materials and Methods.
A study of the toxinogenicity of
F. graminearum
fungal strains was undertaken on rice and wheat grains and the effect of
B. velezensis
BZR 336g and
B. velezensis
BZR 517 strains on the growth of the fungus was studied on wheat grains and by the double cultures method. An experiment to study the effect of a liquid culture and supernatant of bacteria was carried out on wheat grains and the content of DON and ZEN in wheat grains was analyzed by HPLC and enzyme immunoassay.
Results.
It was found that two strains of the fungus
F. graminearum
were able to produce a high level of mycotoxins, while the strain
F. graminearum
60318 had a higher growth rate. The
B. velezensis
BZR 336g and
B. velezensis
BZR 517 strains produced lipopeptide exometabolites and inhibited the growth of the
F. graminearum
60318 strain.
in vitro
, while the content of ZEN remained at the control level.
Conclusion.
The ability of two strains of bacteria
B. velezensis
BZR 336g and
B. velezensis
BZR 517 to suppress the growth of the fungus
F. graminearum
60318, as well as to inhibit the accumulation of mycotoxins in wheat grain
in vitro
, suggests that an increase in the content of antagonist bacteria
B. velezensis
BZR 336g and
B. velezensis
BZR 517 in the wheat microbiota can contribute to the suppression of the growth and harm of the fungus
F. graminearum
60318.
The article describes opportunities and results of laparoscopic oesophagocardiomiotomy and laparoscopic transhiatal oesophagus removal without hand assistance in esophageal achalasia (cardiospasm). ...In total, such operations were performed in 196 and 31 of cases (of 423 patients), respectively. There were minimal numbers of relapses (below 2.3%) after laparoscopic oesophagocardiomiotomy done by the proposed technique. All cases of reflux esophagitis were diagnosed after esophagocardiomiotomy with Dor fundoplication.After cardiodilatation, disease relapses were registered in 57% of patients. The advantages of a laparoscopic access for oesophagectomy are shown and technical particular of this intervention are analyzed based on a case history. The principles of Fast track surgery in this patient category are discussed that allow for reduction of the length of hospital stay by 40%.
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