Paramagnetic-diamagnetic interplay in quantum dots for non-zero temperatures

In the usual Fock-and Darwin-formalism with parabolic potential characterized by the confining energy \eps_o := \hbar\omega_o= 3.37 meV, but including explicitly also the Zeeman coupling between spin and magnetic field, we study the combined orbital and spin magnetic properties of quantum dots in a two-dimensional electron gas with parameters for GaAs, for N =1 and N >> 1 electrons on the dot. For N=1 the magnetization M(T,B) consists of a paramagnetic spin contribution and a diamagnetic orbital contribution, which dominate in a non-trivial way at low temperature and fields rsp. high temperature and fields. For N >> 1, where orbital and spin effects are intrinsically coupled in a subtle way and cannot be separated, we find in a simplified Hartree approximation that at N=m^2, i.e. at a half-filled last shell, M(T,B,N) is parallel (antiparallel) to the magnetic field, if temperatures and fields are low enough (high enough), whereas for N\ne m^2 the magnetization oscillates with B and N as a T-dependent periodic function of the variable x:=\sqrt{N}eB/(2m^*c\omega_o), with T-independent period \Delta x =1 (where m^* := 0.067 m_o is the small effective mass of GaAs, while m_o is the electron mass). Correspondingly, by an adiabatic demagnetization process, which should only be fast enough with respect to the slow transient time of the magnetic properties of the dot, the temperature of the dot diminishes rsp. increases with decreasing magnetic field, and in some cases we obtain quite pronounced effects.Comment: LaTeX, 28 pages; including three .eps-figures; final version accepted by J. Phys. CM, with minimal changes w.r.to v

DIGITALIZATION OF LOGISTICS HUBS AS A COMPETITIVE ADVANTAGE

The article reveals the concept of a logistics unit, logistics and digital hubs. It is considering the possibility of combining the Northern Sea and New Silk Way sections into a single system on the territory of the Russian Federation. The authors investigated the ways of digitalization of the logistics block of the NSR – NSW with the subsequent creation of a virtual space for the control and redistribution of trade throughout the Russian Federation. The concept of a digitalized logistics block is considered from the point of view of a potentially beneficial project for Russia to collect statistical data and accelerate international transport by instantly redistributing routes

Синтез та антивірусна активність похідних [(9-R1-10-R2-3-R-2-оксо-2H-[1,2,4]-триазино[2,3-с]хіназолін-6-іл)тіо]ацетамідів з фрагментами каркасних амінів

Alkylation of potassium 9-R1-10-R2-3-R-2-oxo-2Н-[1,2,4]triazino[2,3 с]quinazolin-6-thiolates by N-cycloalkyl-(cycloalkylaryl-)-2-chloracetamides and interaction of [(9-R1-10-R2-3-R-2-оxo-2H-[1,2,4]triazino[2,3-с]quinazolin-6-yl) thio]acetiс acids imidazolides and chloranhydrides with carcass amines yielded the corresponding amides. The structures of the compounds synthesized have been confirmed by 1H, 13C NMR, LC–MS and EI-MS analysis.The features of 1H, 13C NMR, LC–MS and EI-MS spectra have been described, and characteristic signals have been identified. The compounds synthesized have been studied for their antiviral activity. The results of the antiviral assay have shown that some compounds exhibit a moderate and high activity against the strains studied.The correlation between the structure and the antiviral action has been also discussed. According to the data obtained the conclusion can be made that the combination of carcass amine moieties with the fragment of little known [(9-R1-10-R2-3-R-2-оxo-2H-[1,2,4]-triazino[2,3-с]quinazolin-6-yl)thio]асetic acid results in compounds with a high antiviral activity. High indicators of the antiviral activity of compounds 3.2 and 3.14 against Influenza Type A H3N2 allow to suppose the expediency of further chemical modification of [1,2,4]triazino[2,3-с]quinazoline directed to obtaining new antiviral agents.Алкилирование калий 9-R1-10-R2-3-R-2-оксо-2H-[1,2,4]триазино[2,3-c]хиназолин-6-тиолатов N-циклоалкил-(циклоалкиларил-)-2-хлорацетамидами и взаимодействие имидазолидов и хлорангидридов [(9-R1-10-R2-3-R-2-оксо-2H-[1,2,4]триазино[2,3-c]хиназолин-6-ил)тио]уксусных кислот с каркасными аминами ведет к образованию амидов. Структуру и чистоту синтезированных соединений установлено комплексом физико-химических методов, в частности, 1H-, 13C-NMR, LC–MS и EI-MS анализом. Также были описаны особенности 1H-, 13C-NMR, LC–MS и EI-MS спектров и идентифицированы характеристические сигналы. Синтезированные соединения были исследованы на наличие противовирусной активности. Установлено, что отдельные представители класса синтезированных соединений проявляют умеренную или высокую противовирусную активность по отношению к изучаемым штаммам. Обсуждена корреляция «структура-действие». Согласно полученным данным можно сделать вывод, что комбинация структуры каркасных аминов с фрагментом малоизвестных [(9-R1-10-R2-3-R-2-оксо-2H-[1,2,4]-триазино[2,3-с]хиназолин-6-ил)тио]уксусных кислот позволяет получить вещества с высокой противовирусной активностью. Высокие индикаторы противовирусной активности по отношению к штамму Influenza Type A H3N2 соединений 3.2 и 3.14 дают возможность прогнозировать перспективность дальнейшей химической модификации [1,2,4]триазино[2,3-c]хиназолина, направленной на получение новых противовирусных агентов.Алкілування калій 9-R1-10-R2-3-R-2-оксо-2H-[1,2,4]триазино[2,3-c]хіназолін-6-тіолатів N-циклоалкіл-(циклоалкіларил-)-2-хлорацетамідами та взаємодія імідазолідів та хлорангідридів [(9-R1-10-R2-3-R-2-оксо-2H- [1,2,4]триазино[2,3-c]хіназолін-6-іл)тіо]оцтових кислот з каркасними амінами призвели до утворення відповідних амідів. Структуру та чистоту синтезованих сполук встановлено за допомогою комплексу фізико-хімічних методів, зокрема 1H, 13C-NMR, LC–MS та EI-MS аналізом. Особливості 1H, 13C NMR, LC–MS та EI-MS спектрів були обговорені, також були ідентифіковані характеристичні сигнали. Синтезовані сполуки були досліджені на наявність антивірусної активності. Встановлено, що окремі представники синтезованих сполук виявляють помірну та високу антивірусну активність по відношенню до штамів, що досліджувались. Кореляція взаємозв’язків «будова-дія» була обговорена. Відповідно до одержаних даних ми зробили висновок, що комбінація залишку каркасних амінів з фрагментами маловідомих [(9-R1-10-R2-3-R-2-оксо-2H-[1,2,4]-триазино[2,3-c]хіназолін-6-іл)тіо]оцтових кислот дозволяє одержати сполуки зі значною антивірусною активністю. Високі індикатори антивірусної активності по відношенню до штаму Influenza Type A H3N2 сполук 3.2 та 3.14 дозволяють передбачити перспективність подальшої хімічної модифікації [1,2,4]триазино[2,3-c]хіназоліну з метою пошуку нових антивірусних агентів

Study of the process e+e−→ppˉe^+e^-\to p\bar{p} in the c.m. energy range from threshold to 2 GeV with the CMD-3 detector

Using a data sample of 6.8 pb$^{-1}$ collected with the CMD-3 detector at the VEPP-2000 $e^+e^-$ collider we select about 2700 events of the $e^+e^- \to p\bar{p}$ process and measure its cross section at 12 energy ponts with about 6\% systematic uncertainty. From the angular distribution of produced nucleons we obtain the ratio $|G_{E}/G_{M}| = 1.49 \pm 0.23 \pm 0.30$

WIMP-nucleon cross-section results from the second science run of ZEPLIN-III

We report experimental upper limits on WIMP-nucleon elastic scattering cross sections from the second science run of ZEPLIN-III at the Boulby Underground Laboratory. A raw fiducial exposure of 1,344 kg.days was accrued over 319 days of continuous operation between June 2010 and May 2011. A total of eight events was observed in the signal acceptance region in the nuclear recoil energy range 7-29 keV, which is compatible with background expectations. This allows the exclusion of the scalar cross-section above 4.8E-8 pb near 50 GeV/c^2 WIMP mass with 90% confidence. Combined with data from the first run, this result improves to 3.9E-8 pb. The corresponding WIMP-neutron spin-dependent cross-section limit is 8.0E-3 pb. The ZEPLIN programme reaches thus its conclusion at Boulby, having deployed and exploited successfully three liquid xenon experiments of increasing reach

Measurement of the e+e−→K+K−π+π−e^+e^- \to K^+K^-\pi^+\pi^- cross section with the CMD-3 detector at the VEPP-2000 collider

The process $e^+e^- \to K^+K^-\pi^+\pi^-$ has been studied in the center-of-mass energy range from 1500 to 2000\,MeV using a data sample of 23 pb$^{-1}$ collected with the CMD-3 detector at the VEPP-2000 $e^+e^-$ collider. Using about 24000 selected events, the $e^+e^- \to K^+K^-\pi^+\pi^-$ cross section has been measured with a systematic uncertainty decreasing from 11.7\% at 1500-1600\,MeV to 6.1\% above 1800\,MeV. A preliminary study of $K^+K^-\pi^+\pi^-$ production dynamics has been performed

Use of a Neurometabolism-Targeting Drug in Prevention of Postoperative Cognitive Dysfunction

Aim of the study: to evaluate the feasibility of preventing cognitive dysfunction after long-term surgery in elderly patients using an original neurometabolic succinate-containing drug.   Material and methods. A multicenter, double-blind, placebo-controlled randomized trial enrolled 200 patients aged 60–80 years who underwent elective cardiac or orthopedic surgery. The patients received either the study drug (inosine + nicotinamide + riboflavin + succinate) (treatment group, n = 101) or a placebo (control group, n = 99) intravenously for 7 days then orally for 25 days. Efficacy was assessed by the change in the Montreal Cognitive Assessment Scale (MoCA) score at the end of the treatment course compared with the preoperative level.   Results. Before surgery, the total MoCA score values did not differ between the groups. By the end of the treatment course (31 days after surgery), the MoCA total score was 26.4 ± 1.96 in the main group and 25.0 ± 2.83in the control group (P < 0.001). The intergroup difference in the mean change in the MoCA total score on day 31 was 1.56 points (95 % CI 1.015; 2.113; P < 0.0001) favoring the study drug in all randomized population. The lower limit of CI (1.015) exceeded the limit of superiority set by the protocol (0.97 points), which allowed acceptance of the hypothesis of superiority of the study drug over placebo with respect to the primary efficacy criterion. No significant differences in the frequency of adverse events were found between the groups.   Conclusion. The succinate-containing study drug demonstrated an acceptable safety profile and helped to reduce the severity of postoperative cognitive dysfunction in elderly patients who underwent a major surgery, which allows recommending the drug for prevention of postoperative cognitive impairment in high-risk patients

The UA9 experimental layout

The UA9 experimental equipment was installed in the CERN-SPS in March '09 with the aim of investigating crystal assisted collimation in coasting mode. Its basic layout comprises silicon bent crystals acting as primary collimators mounted inside two vacuum vessels. A movable 60 cm long block of tungsten located downstream at about 90 degrees phase advance intercepts the deflected beam. Scintillators, Gas Electron Multiplier chambers and other beam loss monitors measure nuclear loss rates induced by the interaction of the beam halo in the crystal. Roman pots are installed in the path of the deflected particles and are equipped with a Medipix detector to reconstruct the transverse distribution of the impinging beam. Finally UA9 takes advantage of an LHC-collimator prototype installed close to the Roman pot to help in setting the beam conditions and to analyze the efficiency to deflect the beam. This paper describes in details the hardware installed to study the crystal collimation during 2010.Comment: 15pages, 11 figure, submitted to JINS