On the lifting of the Nagata automorphism

It is proved that the Nagata automorphism (Nagata coordinates, respectively) of the polynomial algebra $F[x,y,z]$ over a field $F$ cannot be lifted to a $z$-automorphism ($z$-coordinate, respectively) of the free associative algebra $K$. The proof is based on the following two new results which have their own interests: degree estimate of ${Q*_FF}$ and tameness of the automorphism group ${\text{Aut}_Q(Q*_FF)}$.Comment: 15 page

Experimental study of weak antilocalization effect in a high mobility InGaAs/InP quantum well

The magnetoresistance associated with quantum interference corrections in a high mobility, gated InGaAs/InP quantum well structure is studied as a function of temperature, gate voltage, and angle of the tilted magnetic field. Particular attention is paid to the experimental extraction of phase-breaking and spin-orbit scattering times when weak anti- localization effects are prominent. Compared with metals and low mobility semiconductors the characteristic magnetic field $B_{tr} = \hbar/4eD \tau$ in high mobility samples is very small and the experimental dependencies of the interference effects extend to fields several hundreds of times larger. Fitting experimental results under these conditions therefore requires theories valid for arbitrary magnetic field. It was found, however, that such a theory was unable to fit the experimental data without introducing an extra, empirical, scale factor of about 2. Measurements in tilted magnetic fields and as a function of temperature established that both the weak localization and the weak anti-localization effects have the same, orbital origin. Fits to the data confirmed that the width of the low field feature, whether a weak localization or a weak anti-localization peak, is determined by the phase-breaking time and also established that the universal (negative) magnetoresistance observed in the high field limit is associated with a temperature independent spin-orbit scattering time.Comment: 13 pages including 10 figure

СТАН СОМАТИЧНОГО ПУЛУ БІЛКА ЯК МАРКЕР ТРОФОЛОГІЧНОГО СТАТУСУ ПРИ ХРОНІЧНОМУ ПАНКРЕАТИТІ, ПОЄДНАНОМУ З ОЖИРІННЯМ

Trophological insufficiency is formed in the long course of chronic pancreatitis (CP).The aim of the study – to learn the main anthropometric indicators that can be used to assess the patient's tropholo­gical status: body mass index (BMI), waist circumference, skin and fat folds over the triceps, muscle circumference shoulder.Material and Methods. 122 patients were examined. Group 1 (control) – 20 healthy people, group 2 – 22 patients with CBP, group 3 – 80 patients with CBP in combination with obesity.Results. Indicators of BMI and waist circumference in the group of patients with CBP patients were (24.66±0.87) kg/m²; (79.76±1.79) cm, and in the group of CBP in combination with obesity – (32.28±3.46) kg/m²; (102.21±9.32) cm respectively. Indicators of skin and fat folds over the triceps and muscle circumference shoulder in the group of patients with CBP were (15.06±1.55) mm; (23.87±0.95) cm, and in the group of CBP in combination with obesity (20.66±2.31) mm; (21.87±0.95) cm. All the anthropometric indices were significantly different in the comparable groups (p<0.05), as well as from the control group.Conclusions. This proved the presence of a decrease in the somatic protein pool in the presence of obesity and noted the presence of trophological insufficiency in patients with chronic biliary pancreatitis, which deepens with the adherence of obesity.При длительном течении хронического панкреатита (ХП) формируется трофологическая недостаточность.Цель – исследовать основные антропометрические показатели, по которым можно оценить трофологичес­кий статус пациента: индекс массы тела (ИМТ), окружность талии (ОТ), кожно-жировая складка над трицепсом (КЖСТ), окружность мышц плеча (ОМП).Материал и методы. Обследовано 122 пациента. 1 группа (контроля) – 20 здоровых людей, 2 группа – 22 больных ХБП, 3 группа – 80 больных ХБП в сочетании с ожирением.Результаты. Показатели ИМТ и ОТ в группе больных ХБП составили (24,66±0,87) кг/м²; (79,76±1,79) см, а в группе больных ХБП с сопутствующим ожирением – (32,28±3,46) кг/м²; (102,21±9,32) см соответственно. Показатели КЖСТ и ОМП в группе больных ХБП составляли (15,06±1,55) мм; (23,87±0,95) см, а в группе ХБП с сопутствующим ожирением – (20,66±2,31) мм; (21,87±0,95) см. Все исследуемые антропометрические показатели достоверно отличались между собой в сравниваемых группах (p<0,05), а также от таких группы контроля, где ИМТ составлял (22,66±0,57) кг/м², ОТ – (75,76±1,70) см, КЖСТ – (12,45±1,43) мм; ОМП – (27,49±1,16) см.Выводы. Установлены нарушения трофологичного статуса в обеих группах больных хроническим билиарным панкреатитом, однако более глубокие изменения были в группе ХБП с сопутствующим ожирением. Это доказало наличие снижения соматического пула белка при ожирении и констатировало наличие трофологической недостаточности у больных ХБП, которая углубляется с присоединением ожирения.При тривалому перебігу хронічного панкреатиту (ХП) формується трофологічна недостатність.Мета – дослідити основні антропометричні показники, за якими можна оцінити трофологічний статус пацієнта: індекс маси тіла (ІМТ), обвід талії (ОТ), шкірно-жирова складка над тріцепсом (ШЖСТ), обвід м'язів плеча (ОМП).Матеріал і методи. Обстежено 122 пацієнти. 1 група (контролю) – 20 здорових людей, 2 група – 22 хворих на ХБП, 3 група – 80 хворих на ХБП в поєднанні з ожирінням.Результати. Показники ІМТ та ОТ у групі хворих з ХБП склали (24,66±0,87) кг/м²; (79,76±1,79) см, а у групі ХБП із супутнім ожирінням – (32,28±3,46) кг/м²; (102,21±9,32) см відповідно. Показники ШЖСТ та ОМП у групі хворих на ХБП становили (15,06±1,55) мм; (23,87±0,95) см, а у групі хворих на ХБП із супутнім ожирінням – (20,66±2,31) мм; (21,87±0,95) см. Усі досліджувані антропометричні показники достовірно відрізнялися між собою у порівнюваних групах (p<0,05), а також від таких групи контролю, у яких ІМТ становив (22,66±0,57) кг/м², ОТ – (75,76±1,70) см, ШЖСТ – (12,45±1,43) мм; ОМП – (27,49±1,16) см.Висновки. Встановлено порушення трофологічного статусу в обох групах хворих на хронічний біліарний панкреатит, проте глибші зміни були у групі ХБП із супутнім ожирінням. Це довело наявність зниження соматичного пулу білка при ожирінні і констатувало трофологічну недостатність у хворих на ХБП, яка поглиблюється із приєднанням ожиріння

Geomagnetic storm dependence on the solar flare class

Content. Solar flares are often used as precursors of geomagnetic storms. In particular, Howard and Tappin (2005) recently published in A&A a dependence between X-ray class of solar flares and Ap and Dst indexes of geomagnetic storms which contradicts to early published results. Aims. We compare published results on flare-storm dependences and discuss possible sources of the discrepancy. Methods. We analyze following sources of difference: (1) different intervals of observations, (2) different statistics and (3) different methods of event identification and comparison. Results. Our analysis shows that magnitude of geomagnetic storms is likely to be independent on X-ray class of solar flares.Comment: 3 pages, 1 tabl

Coordinated multicell beamforming with local and global data rate constraints

© 2016 IEEE.We propose optimization techniques for coordinated multi-cell beamforming in the presence of local users and a global user. The local users are served by only the corresponding basestation (BS) while the global user is served by multiple basestations. The global user, with the aid of multiple antennas, is able to decode multiple data streams transmitted by various transmitters through singular value decomposition of the channels at the receiver and using left dominant singular vectors as the receiver beamforming. The coordinating basestations employ semidefinite programing based transmitter beamforming and agree to perform optimum data rate split for the global user in order to minimise the transmission power

Synchronization of fractional order chaotic systems

The chaotic dynamics of fractional order systems begin to attract much attentions in recent years. In this brief report, we study the master-slave synchronization of fractional order chaotic systems. It is shown that fractional order chaotic systems can also be synchronized.Comment: 3 pages, 5 figure

Fine structure of excitons in Cu2_2O

Three experimental observations on 1s-excitons in Cu$_2$O are not consistent with the picture of the exciton as a simple hydrogenic bound state: the energies of the 1s-excitons deviate from the Rydberg formula, the total exciton mass exceeds the sum of the electron and hole effective masses, and the triplet-state excitons lie above the singlet. Incorporating the band structure of the material, we calculate the corrections to this simple picture arising from the fact that the exciton Bohr radius is comparable to the lattice constant. By means of a self-consistent variational calculation of the total exciton mass as well as the ground-state energy of the singlet and the triplet-state excitons, we find excellent agreement with experiment.Comment: Revised abstract; 10 pages, revtex, 3 figures available from G. Kavoulakis, Physics Department, University of Illinois, Urban

Signatures of Superfluidity in Dilute Fermi Gases near a Feshbach Resonance

We present a brief account of the most salient properties of vortices in dilute atomic Fermi superfluids near a Feshbach resonance.Comment: 6 pages, 1 figure, and jltp.cls. Several typos and a couple of inaccuracies have been correcte

Dynamics of a classical gas including dissipative and mean field effects

By means of a scaling ansatz, we investigate an approximated solution of the Boltzmann-Vlasov equation for a classical gas. Within this framework, we derive the frequencies and the damping of the collective oscillations of a harmonically trapped gas and we investigate its expansion after release of the trap. The method is well suited to studying the collisional effects taking place in the system and in particular to discussing the crossover between the hydrodynamic and the collisionless regimes. An explicit link between the relaxation times relevant for the damping of the collective oscillations and for the expansion is established.Comment: 4 pages, 1 figur