Computer simulation of electron-positron pair production by channeling radiation in amorphous converter

We consider the radiator-converter approach at 200 MeV channeled electrons (the SPARC_LAB LNF facility energies) for the case of using W crystalline radiator and W amorphous converter. A comparison of the positron production by the axial channeling radiation and the bremsstrahlung is performed. The positron stopping in the convertor is studied by means of computer simulations. It is shown that for the maximum yield of positrons the thickness of the W amorphous converter should be taken 0.35 cm in the case of using the axial channeling radiation resulting to total yield of positrons 5 10[-3]e+/e and 0.71 cm in the case of using the bremsstrahlung resulting to total yield of positrons 3.3 10[-3]e+/e-

Получение удвоенных гаплоидов огурца (Cucumis sativus L.)

Implementation of cell technologies has essentially improved the plant breeding process in agricultural crops in the world. The production of pure lines in cultivated crops, particularly among cross-pollinated species such as cucumber (Cucumis sativus L.) requires much time, labor and expense. Thus, the use of DH-plants for production of fully homozygous lines for one year becomes a very promising method for near cucumber breeding program. The major factor limiting the wide use of DH is a lack of effective protocol for large-scale plant production. In this review the historical facts with description of three main methods of DH-plant production were presented. By now these three methods have been such as parthenogenesis in situ induced by pollination with irradiated or chemically treated pollen; androgenesis in vitro including anther and isolated microspore cultivation in vitro; gynogenesis through ovule cultivation in vitro. Comparative analysis of published data with regard to the efficiency of the technology for DH-plant production was shown as well as advantages and limitations of each technology were described.Разработка и внедрение клеточных технологий существенно изменили селекционный процесс у сельскохозяйственных растений во всем мире. Производство чистых линий у сельскохозяйственных культур, особенно у перекрестноопыляемых растений, таких как огурец (Cucumis sativus L.), требует больших временных и трудовых затрат, а также и достаточных финансовых вложений. В связи с этим использование удвоенных гаплоидов (DH-растений) для получения полностью гомозиготных линий в течение одного года представляет большой интерес для современной селекции, в том числе у этой культуры. Важнейшим фактором, препятствующим использованию DH-растений в селекции огурца, является отсутствие эффективного способа их производства в больших масштабах. В обзоре представлены исторические факты и рассмотрены три основных способа получения удвоенных гаплоидов огурца: партеногенеза in situ (опыление неполноценной (облученная или обработанная химическими веществами) пыльцой); андрогенеза (культуры пыльников/микроспор in vitro); гиногенеза (культура неопыленных семяпочек in vitro). Произведен сравнительный анализ публикаций с учетом эффективности использующихся технологий, выявлены критические факторы, влияющие на выход гаплоидных и удвоенных гаплоидных растений, указаны преимущества и ограничения каждой из технологий

Liquid krypton electromagnetic calorimeter

Abstract A calorimeter using 30 tons of liquid krypton for the KEDR detector is being constructed. The main effects which determine the energy and space resolution have been studied. An energy resolution of 1.7% at 1.2 GeV was obtained with the prototype. A space resolution of 0.4 mm for relativistic particles has been reached with the prototype

Measurement of prompt open-charm production cross sections in proton-proton collisions at root s=13 TeV

The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb(-1). The differential production cross sections of the D*(+/-), D-+/-, and D-0 ((D) over bar (0)) mesons are presented in ranges of transverse momentum and pseudorapidity 4 < p(T) < 100 GeV and vertical bar eta vertical bar < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.Peer reviewe

Measurement of B-c(2S)(+) and B-c*(2S)(+) cross section ratios in proton-proton collisions at root s=13 TeV

Peer reviewe

Observation of the Production of Three Massive Gauge Bosons at root s=13 TeV

The first observation is reported of the combined production of three massive gauge bosons (VVV with V = W, Z) in proton-proton collisions at a center-of-mass energy of 13 TeV. The analysis is based on a data sample recorded by the CMS experiment at the CERN LHC corresponding to an integrated luminosity of 137 fb(-1). The searches for individualWWW, WWZ, WZZ, and ZZZ production are performed in final states with three, four, five, and six leptons (electrons or muons), or with two same-sign leptons plus one or two jets. The observed (expected) significance of the combinedVVV production signal is 5.7 (5.9) standard deviations and the corresponding measured cross section relative to the standard model prediction is 1.02(-0.23)(+0.26). The significances of the individual WWW and WWZ production are 3.3 and 3.4 standard deviations, respectively. Measured production cross sections for the individual triboson processes are also reported