The Multi-Purpose Detector (MPD) is under construction to investigate heavy ion collisions at the NICA collider in the energy range sNN=4−11GeV. The MPD physics purpose is to get a better ...understanding of the QCD matter under extreme conditions of high baryonic density by studying collective phenomena, Λ polarization, dilepton yields, multi-strange hyperons and hypernuclei production. The MPD construction is progressing in accordance with the schedule.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Saline rivers are highly productive ecosystems in arid regions. The meiobenthic community (bottom meiofauna) and its dominant representatives are one of the least studied components of these aquatic ...ecosystems. Ostracods Cyprideis torosa and Heterocypris salina are major consumers among the species of bottom meiofauna in saline rivers flowing into the hyperhaline Lake Elton (Volgograd Region, Russia). We estimated the abundance, biomass and production of C. torosa, the dominant species at the mouth of the polyhaline Chernavka River (average salinity is ~30 g l^(-1)), and H. salina, the dominant species at the mouth of the mesohaline Bolshaya Samoroda River (~13 g l^(-1)), in spring (May) and summer (August). Additionally, we studied the composition and content of fatty acids of the ostracods and their potential food sources (bottom sediments with bacterial-algal mats). We found that the abundance and biomass (wet weight with shells) of C. torosa in the Chernavka River and H. salina in the Bolshaya Samoroda River reached 3.5 × 10^6 ind. m^(-2) and 117 g m^(-2), and 1.1 × 10^5 ind. m^(-2) and 12 g m^(-2), respectively. The first species formed on average about 85% of the total abundance and 96% of the total biomass of the meiobenthos, and the second one, about 13% and 31%, respectively. The daily production of C. torosa and H. salina can reach 249 and 36 mg m^(-2) ash-free dry weight, respectively. The results indicate that these species may play an important role in the total flow of matter and energy in the studied habitats. Based on the fatty acid (FA) composition of the ostracods and their food sources, it was found that C. torosa mainly consumed diatoms, while H. salina preferred bacteria, cyanobacteria, and green algae. Differences between the species were greater than differences between the bottom sediments from the rivers. It may mean that the ostracods selectively consumed different food items that may be related to the different nutrient requirements of the species. Seasonal changes in the FA compositions of the ostracods were higher than in their food sources (bottom sediments), which also indicates selective feeding of the species.
The rise of salinity of inland waters in many regions of the world highlights the necessity of investigations of ecosystems with a naturally high level of salinity to be able to predict possible ...changes in freshwater under the influence of modern environmental hazards. We studied species composition, density, biomass, and estimated production of macrozoobenthos communities in the middle reach and mouth of the saline Chernavka River (Lake Elton basin, Russia) from October 2018 to September 2019. The salinity of the water varied from 24 to 34 g l
−1
during the investigation period. Species richness was poor: only a total of 21 taxa were found during the study period in the Chernavka River. The average density of benthic taxa in the middle reach was 8294 ind. m
−2
, and in the river mouth, the average density of benthic taxa was 12,893 ind. m
−2
. Chironomid larvae and Ceratopogonid larvae had high density and biomass in both sites throughout the growing season. Beetle larvae had high density in summer and autumn in the mouth of the river. The production of macrozoobenthos in the middle reach was 57.7 g dry wt m
−2
year
−1
. In the mouth reach, the production was 707.2 g dry wt m
−2
year
−1
. In the middle reach, the greatest contribution to production was made by
Palpomyia schmidti
,
Cricotopus salinophilus
, and
Ephydra
sp. In the mouth reach,
Chironomus salinarius
,
Berosus
spp., and
C. salinophilus
contributed to benthic production the most.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This study investigated the species composition, distribution, and salinity tolerance of macrozoobenthos in 17 small rivers in the southern arid region of the East European Plain, which are ...characterized by a small channel gradient, slow-flowing or stagnant water bodies, and a wide range of water salinity, varying between 0.18 and 30 g L−1. In total, 156 taxa were found, among which 66 were Diptera species. The study revealed that the formation of benthic communities in the rivers is influenced by natural factors of the catchment basins, including the flat landscape with sparsely developed relief differentiation, climate aridity, and the widespread occurrence of saline soils and groundwater, largely related to the sedimentation of the ancient Caspian Sea and modern climate changes. These conditions are favorable for the occurrence of lacustrine macrozoobenthic species in freshwater, euryhaline, and halophilic ecological groups. The investigation revealed a decrease in species richness in response to an increase in water salinity. The five identified halophilic species Tanytarsus kharaensis, Glyptotendipes salinus, Cricotopus salinophilus, Chironomus salinarius, and Palpomyia schmidti can be used as indicators of river ecosystem salinization.
A new Time-of-Flight (ToF) detector of the NA61/SHINE hadron spectrometer at CERN SPS based on Multigap Resistive Plate Chambers (MRPCs) technology is offered as a substitution of the scintillation ...ToF detector developed in 1990s. In 2019–2020, a prototype module of the new ToF system was tested on the 280 MeV/c positron beam to determine its characteristics. The analogue front-end electronics and DRS4-based waveform digitizer were used as a readout chain. This article presents the results of the MRPC test with analogue readout obtained in 2019–2020.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
The NICA facility is under active realization at the Joint Institute for Nuclear Research (JINR, Dubna). Its main goal includes experimental studies of hot and dense baryon rich matter ...forming in heavy ion collisions to search for possible manifestations of phase transitions and critical phenomena, as well as investigation of nucleon spin structure with polarized proton and deuteron beams. The NICA general design, construction status, and prospects for physics program are presented.
Abstract
The Multi Purpose Detector (MPD) is one of the detectors at
the NICA collider and the Electromagnetic Calorimeter (ECal) is an
important part of MPD. The cylindrical ECal system consists of ...2400
ECal modules. In the first stage (2020–2024), Tsinghua University
(THU) will produce 460 ECal modules for MPD project. This article
mainly introduces the production, quality control and cosmic ray
test of ECal modules in THU. The process flow, quality control
standards, and testing system of ECal production have been
established, which guarantees the high-quality completion of mass
production on schedule. Up to now, nearly 360 modules have been
manufactured, and a total of 460 modules will be produced by June
2022.
New NICA accelerator complex at JINR (Dubna), based on the existing upgraded Nuclotron accelerator, will allow conducting all types of research in the field of high-energy physics. The main tasks of ...this project are study of the properties of the deconfinement phase transition, experimental investigation on medium modification of vector mesons, and search for the QCD critical end point. Thus, two interaction points are foreseen in the NICA collider: one for studying the collision of heavy ions on the Multipurpose detector MPD, the other for polarized beams for the experiment on the SPD installation. The ambitious physical goals of MPD require excellent particle identification at the maximum possible range of phase space. Identification of charged hadrons is achieved by combining time-of-flight measurements and
energy loss measurements from the time-projection camera TPC. The Time-of-Flight system is based on multigap resistive plate chambers (MRPC), which are successfully used to identify particles in similar experiments around the world. A production site has been organized at the Laboratory of High Energy Physics of JINR for serial production of TOF MPD modules including 10 MRPCs. This site includes the entire cycle of work from preparing materials for the assembly of detectors to testing the assembled modules on cosmic radiation. This report presents the structure of the TOF system, its main parameters, the current state and the results of decoding and processing data obtained at the module testing facility.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The results of long-term studies of biting midges (Diptera, Ceratopogonidae) in macrozoobenthos communities of five saline rivers of the hyperhaline Lake Elton basin are presented. The fauna of ...Ceratopogonidae includes five halophilic and euryhaline species, among which representatives of the tribe Sphaeromiini predominate. The taxonomic composition of the family differs in rivers with different levels of salinity. Species
Sphaeromias miricornis
and
Culicoides riethi
are widely distributed in the mesohaline Khara, Lantsug, and Bolshaya Samoroda rivers, and
Palpomyia schmidti
is widely distributed in the polyhaline Chernavka and Solyanka rivers. Two generations of
S. miricornis
and three generations of
P. schmidti
are recorded. The emergence of the first generation of
P. schmidti
occurs in mid-May;
S. miricornis
emerges in late May to early June. There is an increase in the mean annual abundance and biomass of biting midges in polyhaline rivers when compared with mesohaline rivers.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Results on
ϕ
meson production in inelastic
p
+
p
collisions at CERN SPS energies are presented. They are derived from data collected by the NA61/SHINE fixed target experiment, by means of invariant ...mass spectra fits in the
ϕ
→
K
+
K
-
decay channel. They include the first ever measured double differential spectra of
ϕ
mesons as a function of rapidity
y
and transverse momentum
p
T
for proton beam momenta of
80
GeV
/
c
and
158
GeV
/
c
, as well as single differential spectra of
y
or
p
T
for beam momentum of
40
GeV
/
c
. The corresponding total
ϕ
yields per inelastic
p
+
p
event are obtained. These results are compared with existing data on
ϕ
meson production in
p
+
p
collisions. The comparison shows consistency but superior accuracy of the present measurements. The emission of
ϕ
mesons in
p
+
p
reactions is confronted with that occurring in
Pb
+
Pb
collisions, and the experimental results are compared with model predictions. It appears that none of the considered models can properly describe all the experimental observations.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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