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Using morphological traits and molecular-genetic research methods, the authors have identified 24 species of naked amoeba from natural biotopes. The 18S rRNA gene sequences were obtained for the following species of naked amoeba: Amoeba proteus isolate AP07 (ON907618), Saccamoeba limax isolate SLU_22 (OP894078), Saccamoeba limax isolate SL_Uk19 (OQ520144), Saccamoeba sp. strain IDL777 (MZ079370), Thecamoeba striata isolate THS19 (OQ134482), Thecamoeba striata isolate THS20 (OQ134483), Thecamoeba similis isolate Prut river (OL604177), Thecamoeba similis isolate Baggersee Innsbruck (Baggersee Rossau) (OL604178), Thecamoeba quadrilineata isolate THQD2 (ON398269), Thecamoeba quadrilineata isolate THQA1 (ON398268), Thecamoeba sp. strain THS203 (MZ079371), Stenamoeba stenopodia isolate UKSS7 (OP375108), Stenamoeba stenopodia isolate POLSS7 (OP419588), Korotnevella stella isolate KSD2 (ON398267), Korotnevella stella isolate KSA1 (ON398266), Vexillifera bacillipedes isolate river Dnepr (OK649262), Vannella lata isolate Kamenka river (OL305063), Vannella lata isolate Varta river (OL305064), Vannella sp. strain VLS303 (MZ079372), Vannella simplex isolate Black Sea (OM403052), Vannella simplex isolate Mediterranean Sea (OM403053), Ripella sp. strain RPL100 (MZ079369), Mayorella vespertilioides isolate MV_7 (OP739500), Mayorella sp. isolate MY_7 (OP729930), Acanthamoeba sp. strain ATM123 (MZ079366), Acanthamoeba sp. isolate river Elbe (OK649261), Acanthamoeba polyphaga isolate AcPoly01 (ON908497), Acanthamoeba polyphaga isolate AcPoly15 (ON908496), Acanthamoeba griffini isolate Black sea (OM522832), Acanthamoeba griffini isolate Mediterranean Sea (OM522833), Cochliopodium actinophorum strain COP101 (MZ079367), Cochliopodium minus isolate river Stokhid (OK649264), Cochliopodium sp. strain COP102 (MZ079368), Vahlkampfia avara isolate VA7 (OP179657), Willaertia magna isolate river Teterev (OK649263). All of the naked amoebae species on the phylogenetic tree constructed based on the 18S rRNA gene are located within Amoebozoa and grouped with Tubulinea and Discosea. There are separate groups of freshwater, marine, and terrestrial biotopes; these groups are sister species relative to one another with low results of bootstrap analysis, which shows a low accuracy in the distances of particular amoeba species isolated from different natural biotopes.

In the water bodies of Ukraine, 6 new species of naked amoebae were found: Saccamoeba sp., Ripella sp., Vannella lata Page, 1988, The camoeba sp., Acanthamoeba sp., Vahlkampfia sp. According to the current taxonomy, they belong to 3 classes, 4 orders, 5 families and 6 genera. New localities and original descriptions of the species are presented, along with brief characteristics of the corresponding genera. The camoeba sp. and Acanthamoeba sp. are first reported from the territory of Ukraine.

The biotopic and seasonal distributions of the naked amoeba species related to the specific morphotypes were analyzed on the territory of Zhytomyr and Volyn Polissya. It was demonstrated that the polytactic and, to some extent, rugose and branched morphotypes of naked amoebas have the adaptive significance and could have emerged as a result of adaptation to characteristic conditions of oligotrophic lakes. In turn, the formation of lanceolate morphotype may be associated with the adaptation to low water temperatures, whereas the formation of flamellian morphotype may be an adaptation to high temperatures.

The GlueX experiment at Jefferson Laboratory aims to perform quantitative tests of non-perturbative QCD by studying the spectrum of light-quark mesons and baryons. A Detector of Internally Reflected Cherenkov light (DIRC) was installed to enhance the particle identification (PID) capability of the GlueX experiment by providing clean π /K separation up to 3.7 GeV/ c momentum in the forward region ( θ < 11°), which will allow the study of hybrid mesons decaying into kaon final states with significantly higher efficiency and purity. The new PID system is constructed with radiators from the decommissioned BaBar DIRC counter, combined with new compact photon cameras based on the SuperB FDIRC concept. The full system was successfully installed and commissioned with beam during 2019/2020. The initial PID performance of the system was evaluated and compared to one from Geant4 simulation.

Taxonomy of naked amoebae and specifics of their distribution in water bodies of Sumy Region are presented. Our research identified 12 species of naked amoebae of 11 morphotypes. We established their ecological groups relative to abiotic aquatic factors: euryoxidic, stenooxidic, stenobiotic and those that survive in a wide range of organic matter content. According to the species composition, swamp and riparian species complexes of naked amoebae were identified. It was found that species complexes of amoeba are influenced by such factors as temperature, concentration of dissolved oxygen and organic compounds.

The species Rhzamoeba sp., Thecamoeba quadrilineata Carter, 1856, Thecamoeba verrucosa Ehrenberg, 1838, Flamella sp., and Penardia mutabilis Cash, 1904 are first reported in the fauna of Ukraine and described based on original material.

NICA-Nuclotron (Nuclotron-based Ion Collider fAility) is a new accelerator complex being constructed at the Joint Institute for Nuclear Research (Dubna, Russia) to study properties of dense baryonic matter. BM@N (Baryonic Matter at Nuclotron) is the first fixed target experiment at the NICA-Nuclotron facility. The aim of the experiment is to study collisions of relativistic ion beams of the kinetic energy from 1 to 4.5 AGeV with fixed targets. BM@N energies are perfectly suitable for strange hypernuclei investigation. This year BM@N started a new physics program aiming at studying the Short Range Correlations (SRC). SRC are brief fluctuations of two nucleons with high and opposite momenta, where each of them is higher than the Fermi momentum for the given nucleus, and the center of mass momentum is close to zero. The presence of SRC pairs within nuclei and their properties have important implications for nuclear physics, high energy physics, and astrophysics. The BM@N setup uses a carbon beam hitting a liquid hydrogen target, which makes it possible to detect the residual nucleus after hard knock-out of the two SRC nucleons. We present an overview of the main detection systems used for the SRC measurement as well as the first results from the tracking detectors.

New Gymnamoebae Species (Gymnamoebia) in the Fauna of Ukraine Information is given on new in the fauna of Ukraine gymnamoebae species: [Saccamoeba stagnicola] Page, 1974; [Mayorella] sp.; [Korotnevella] sp.; [Paradermamoeba levis] Smirnov et Goodkov, 1994; [Paradermamoeba valamo] Smirnov et Goodkov, 1993 and [Stenamoeba stenopodia] Smirnov, Nassonova, Chao et Cavalier-Smith, 2007.

The atomic nucleus is made of protons and neutrons (nucleons), which are themselves composed of quarks and gluons. Understanding how the quark–gluon structure of a nucleon bound in an atomic nucleus is modified by the surrounding nucleons is an outstanding challenge. Although evidence for such modification—known as the EMC effect—was first observed over 35 years ago, there is still no generally accepted explanation for its cause 1 – 3 . Recent observations suggest that the EMC effect is related to close-proximity short-range correlated (SRC) nucleon pairs in nuclei 4 , 5 . Here we report simultaneous, high-precision measurements of the EMC effect and SRC abundances. We show that EMC data can be explained by a universal modification of the structure of nucleons in neutron–proton SRC pairs and present a data-driven extraction of the corresponding universal modification function. This implies that in heavier nuclei with many more neutrons than protons, each proton is more likely than each neutron to belong to an SRC pair and hence to have distorted quark structure. This universal modification function will be useful for determining the structure of the free neutron and thereby testing quantum chromodynamics symmetry-breaking mechanisms and may help to discriminate between nuclear physics effects and beyond-the-standard-model effects in neutrino experiments. Simultaneous high-precision measurements of the EMC effect and short-range correlated abundances for several nuclei reveal a universal modification of the structure of nucleons in short-range correlated neutron–proton pairs.

The atomic nucleus is one of the densest and most complex quantum-mechanical systems in nature. Nuclei account for nearly all the mass of the visible Universe. The properties of individual nucleons (protons and neutrons) in nuclei can be probed by scattering a high-energy particle from the nucleus and detecting this particle after it scatters, often also detecting an additional knocked-out proton. Analysis of electron- and proton-scattering experiments suggests that some nucleons in nuclei form close-proximity neutron–proton pairs 1 – 12 with high nucleon momentum, greater than the nuclear Fermi momentum. However, how excess neutrons in neutron-rich nuclei form such close-proximity pairs remains unclear. Here we measure protons and, for the first time, neutrons knocked out of medium-to-heavy nuclei by high-energy electrons and show that the fraction of high-momentum protons increases markedly with the neutron excess in the nucleus, whereas the fraction of high-momentum neutrons decreases slightly. This effect is surprising because in the classical nuclear shell model, protons and neutrons obey Fermi statistics, have little correlation and mostly fill independent energy shells. These high-momentum nucleons in neutron-rich nuclei are important for understanding nuclear parton distribution functions (the partial momentum distribution of the constituents of the nucleon) and changes in the quark distributions of nucleons bound in nuclei (the EMC effect) 1 , 13 , 14 . They are also relevant for the interpretation of neutrino-oscillation measurements 15 and understanding of neutron-rich systems such as neutron stars 3 , 16 . Electron-scattering experiments reveal that the fraction of high-momentum protons in medium-to-heavy nuclei increases considerably with neutron excess, whereas that of high-momentum neutrons decreases slightly, in contrast to shell-model predictions.