A
bstract
The cross section of the process
e
+
e
−
→
π
+
π
−
has been measured in the Spherical Neutral Detector (SND) experiment at the VEPP-2000
e
+
e
−
collider VEPP-2000 in the energy region 525
...<
s
<
883 MeV. The measurement is based on data with an integrated luminosity of about 4.6 pb
−
1
. The systematic uncertainty of the cross section determination is 0.8% at
s
>
0
.
600 GeV. The
ρ
meson parameters are obtained as
m
ρ
= 775
.
3 ± 0
.
5 ± 0
.
6 MeV, Γ
ρ
= 145
.
6 ± 0
.
6 ± 0
.
8 MeV,
B
ρ
→
e
+
e−
×
B
ρ
→
π
+
π−
= (4
.
89 ± 0
.
02 ± 0
.
04) × 10
−
5
, and the parameters of the
e
+
e
−
→
ω
→
π
+
π
−
process, suppressed by
G
-parity, as
B
ω
→
e
+
e−
×
B
ω
→
π
+
π−
= (1
.
32 ± 0
.
06 ± 0
.
02) × 10
−
6
and and
ϕ
ρω
= 110
.
7 ± 1
.
5 ± 1
.
0 degrees.
The layers of a high-temperature novel GaAs:Fe diluted magnetic semiconductor (DMS) with an average Fe content up to 20 at. % were grown on (001) i-GaAs substrates using a pulsed laser deposition in ...a vacuum. The transmission electron microscopy (TEM) and energy-dispersive x-ray spectroscopy investigations revealed that the conductive layers obtained at 180 and 200 ºC are epitaxial, do not contain any second-phase inclusions, but contain the Fe-enriched columnar regions of overlapped microtwins. The TEM investigations of the non-conductive layer obtained at 250 ºC revealed the embedded coherent Fe-rich clusters of GaAs:Fe DMS. The x-ray photoelectron spectroscopy investigations showed that Fe atoms form chemical bonds with Ga and As atoms with almost equal probability and thus the comparable number of Fe atoms substitute on Ga and As sites. The n-type conductivity of the obtained conductive GaAs:Fe layers is apparently associated with electron transport in a Fe acceptor impurity band within the GaAs band gap. A hysteretic negative magnetoresistance (MR) was observed in the conductive layers up to room temperature (RT). MR measurements point to the out-of-plane magnetic anisotropy of the conductive GaAs:Fe layers related to the presence of the columnar regions. The studies of the magnetic circular dichroism confirm that the layers obtained at 180, 200 and 250 ºC are intrinsic ferromagnetic semiconductors and the Curie point can reach up to at least RT in case of the conductive layer obtained at 200 ºC. It was suggested that in heavily Fe-doped GaAs layers the ferromagnetism is related to the Zener double exchange between Fe atoms with different valence states via an intermediate As and Ga atom.
The electromagnetic CsI(Tl) calorimeter is one of the key systems in the Belle II detector. The calorimeter is aimed primarily at efficiently detecting photons over a wide energy range from several ...tens of MeV units to
GeV. A highly efficient data acquisition system is required for a continuous readout of signal events at a trigger rate corresponding to the maximum collider luminosity. Problems solved by such a system for the calorimeter of the Belle II detector are described.
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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 are presented from measuring the
cross section and effective neutron timelike form factor. Data are collected in 2020–2021 at the VEPP-2000
collider in the 1891 to 2007 MeV center-of-mass ...range of energies. The general purpose nonmagnetic SND detector is used to detect neutron–antineutron events. The time-of-flight approach is used to select
events. The measured cross section is 0.4–0.6 nbn. The neutron form factor in the investigated range of energies varies from 0.3 to 0.2.
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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 review is focused on the applicability of virtual reality (VR) and 3D immersive technologies for isolation experiments of human–robot interaction during intravehicular activities (IVAs) and ...scenarios of unmanned aerial vehicles (UAVs) operations on a lunar station. The investigation resulted in the following: (1) a description of UAV prototypes for inspecting confined spaces on Earth, which makes it possible to reproduce the use of multicopter UAVs on the lunar station using VR tools; (2) justification for the use of autonomous UAVs during intravehicular activity (IVA) on the lunar station, taking into account the experience of developing NASA Free-Flyers Units Astrobee (FFU) on the International Space Station; (3) justification for the use of VR tools based on the original VirSim system in relation to IVA at the lunar station. The imitative VR models and suggested research tasks include the following: (1) UAV scenarios, routing, and scheduling, (2) modeling autonomous navigation and control (local positioning and navigation) inside the station, (3) manual piloting, (4) virtual and real control panels, (5) comparison of displays representing UAVs cameras stream, 2D-electronic maps, and real-time 3D-images, and (6) UAV scenarios for potential danger to the lunar station, and support of response to unexpected events. Knowledge from the isolation studies can substantiate guidelines on UAV operations aboard habitable lunar stations.
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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
cross section is measured in the center-of-mass energy range from 1.07 to 2.00 GeV in the decay channel
,
. The data set with an integrated luminosity of 242 pb
accumulated in the experiment with ...the SND detector at the VEPP-2000
collider is analyzed.
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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
Sialadenectomy in young rats modifies the development of the spermatogenic and steroidogenic functions of the testes. Sialadenectomy causes ultrastructural changes in spermatogenic cells, ...sustentocytes, and Leydig cells that disappear by week 8 of the experiment due to realization of compensatory and adaptive mechanisms. The effects of endocrine factors of the greater salivary glands on the spermatogenic cells are realized directly and indirectly via interstitial endocrinocytes and sustentocytes.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Aim.
To obtain extended data on the impact of collateral circulation on the recovery of left ventricular (LV) function after recanalization of chronic coronary total occlusion (CTO), especially in ...patients with reduced left ventricle ejection fraction (LVEF).
Material and methods.
This single-center, prospective, non-randomized study included 20 patients with single-vessel CTO with reduced LVEF (<50%), confirmed by magnetic resonance imaging (MRI), who underwent successful recanalization. All patients were divided into 2 groups depending on the severity of collateral circulation. After 1, 3 and 6 months, MRI was repeated to assess LV function recovery.
Results.
All patients had prior myocardial infarction, while in 70% of cases — in the area of the occluded artery. A previous attempt to recanalize CTO was noted in 30%. The mean baseline LVEF according to echocardiography was 38,80±6,72%. The most common target vessel was the right coronary artery (n=17, 85%), followed by the circumflex and anterior descending arteries — 1 (5%) and 2 (10%) patients, respectively. In the group with high collateral circulation, the initial LVEF according to MRI was higher compared to the group with mild collateral circulation (35,8±7,33% vs 30,7±8,82%, p=0,17). After 6 months, MRI showed significant changes in end-diastolic volume (from 226±71,1 ml to 203±55,2 ml) and LV endsystolic volume (from 153±72,8 ml to 118±57,6 ml), as well as mean increase in LVEF by 3,3%, 4,8% and 5,2% at 1, 3 and 6 months, respectively (p=0,01 compared with baseline). The predictors of LVEF recovery in multivariate regression analysis were the initial LVEF according to MRI, and the filling rate of distal CTO bed on coronary angiography (R
2
=0,63).
Conclusion.
Successful percutaneous coronary intervention with CTO improves LV function in patients with ischemic cardiomyopathy, regardless of the degree of collateral circulation. LV function recovery generally occurs within 3 months after revascularization.
Unprecedented advances of recent decades in clinical pharmacology, cardiac surgery, arrhythmology, and cardiac pacing have significantly improved the prognosis in patients with chronic heart failure ...(CHF). However, unfortunately, heart failure continues to be associated with high mortality. The solution to this problem consists in simultaneous comprehensive use in clinical practice of all relevant capabilities of continuously improving methods of heart failure treatment proven to be effective in randomized controlled trials (especially when confirmed by the results of studies in real clinical practice), on the one hand, and in development and implementation of innovative approaches to CHF treatment, on the other hand. This is especially relevant for CHF patients with mildly reduced and preserved left ventricular ejection fraction, as poor evidence base for the possibility of improving the prognosis in such patients cannot justify inaction and leaving them without hope of a clinical improvement in their condition. The lecture consistently covers the general principles of CHF treatment and a set of measures aimed at inotropic stimulation and unloading (neurohormonal, volumetric, hemodynamic, and immune) of the heart and outlines some promising areas of disease-modifying therapy.
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