L1-norm error bounds for asymptotic expansions of multivariate scale mixtures and their applications to Hotelling's generalized T02

AbstractThis paper is concerned with the distribution of a multivariate scale mixture variate X=(X1,…,Xp)′ with Xi=SiZi, where Z1,…,Zp are i.i.d. random variables, Si>0(i=1,…,p), and {S1,…,Sp} is independent of {Z1,…,Zp}. First we obtain L1-norm error bounds for an asymptotic expansion of the density function of X in the multivariate case as well as in the univariate case. Then the results are applied in obtaining error bounds for asymptotic expansions of the null distribution of Hotelling's generalized T02-statistic. The special features of our results are that our error bounds are given in explicit and computable forms. Further, their orders are the same as ones of the usual order estimates, and hence the paper provides a new proof for validity of the asymptotic expansions

The charge trapping/emission processes in silicon nanocrystalline nonvolatile memory assisted by electric field and elevated temperatures

In this work, the influence of elevated temperatures on charge trapping in Si nanoclusters located in oxide layer of MOS structure has been comprehensively studied. The samples with one layer of nanocrystals in the oxide have been studied using the modular data acquisition setup for capacitance-voltage measurements. The memory window formation and memory window retention experimental methods were used with the aim to study the trapping/emission processes inside the dielectric layer of MOS capacitor memory within the defined range of elevated temperatures. The trap activation energy and charge localization were determined from measured temperature dependences of charge retention. The electric field dependence of the activation energy with subsequent charge emission law have been determined

Long-term results of posterior anchorage of subaxial vertebra in acute unstable trauma

Aim: to study long-term results of posterior anchorage of subaxial vertebra in acute trauma. Material and Methods. We conducted an analysis of long-term results of posterior anchorage of subaxial vertebra in 17 patients with acute unstable trauma which had undergone complex clinical neurological and instrumental investigation, surgical treatment performed from dorsal approach, and the estimation of long-term results in preoperative period. Results. The obtained data indicate the method of transarticular anchorage to be effective and safe and not to have any negative effect on biomechanical properties of cervical spine in the long-term postoperative period. Conclusion. The use of posterior anchorage in acute unstable trauma is most reasonable in subaxial injuries accompagnied by the deformities of medial and posterior spinal columns.</p

Metabolic shifts in subjects with potential risk of primary osteoarthritis

The Aim of the study was to estimate metabolic disorders in subjects with potential risk of primary knee osteoarthri-tis development. Material and Methods. The study included 27 patients: 10 men (37%), 17 women (63%) aged from 33 to 68 years, and 20 healthy people (8 men and 12 women). Traditional biochemical indexes characterizing certain metabolic aspects (total protein, urea, cholesterol, glucose, uric acid, amylase and bilirubin) were studied alongside with the assessment of articular cartilage state by the level of COMP (cartilage oligometric matrix protein), malondial-dehyde and ceruloplasmin. Results. In the course of our investigation we observed elevated COMP (Me=871,4 (792,2; 912,5)), malondialdehyde (Me=5,1 (4,7; 5,5)) and ceruloplasmin (Me=48,4 (41,2; 55,4)) levels. Conclusion. Negative metabolic shifts in the form of cartilage tissue metabolic disorders, activated lipid peroxidation and relative failure of body antioxidant system were observed in patients with potentially high risk of knee osteoarthritis without clinical manifestations of the disease.</p

Two electrons in an external oscillator potential: hidden algebraic structure

It is shown that the Coulomb correlation problem for a system of two electrons (two charged particles) in an external oscillator potential possesses a hidden $sl_2$-algebraic structure being one of recently-discovered quasi-exactly-solvable problems. The origin of existing exact solutions to this problem, recently discovered by several authors, is explained. A degeneracy of energies in electron-electron and electron-positron correlation problems is found. It manifests the first appearence of hidden $sl_2$-algebraic structure in atomic physics.Comment: 7 pages (plus one figure avaliable via direct request), LaTeX, Preprint IFUNAM FT 94-4

The tactics of surgical treatment in metastatic lesions of upper cervical spine.

We demonstrated a successful case of surgical treatment of the patient with metastatic lesion of upper cervical spine with respect to multidisciplinary approach. We performed simultaneous two-stage surgical intervention, the first stage being occipitospondylodesis by multi-segment construction; and second —tumor resection from expanded combined access. It has been stated that the proposed surgical tactics allows performing curative resection in one surgical session without neurological deficit buildup in the postoperative period.</p

Decameter pulsar/transient survey of northen sky. First results

The decameter pulsar/transient survey is now being made using the UTR-2 radio telescope. The survey strategy and parameters, equipment characteristics, data processing algorithms as well as preliminary results are described. The very first result was the discovery of decameter emission of the pulsar J0240+62. Test measurements have shown the sensitivity, reached in the present survey, being 5 Jy for the transient signals, and several mJy – for the periodic pulsar emission.Наразі на радіотелескопі УТР-2 здійснюється декаметровий огляд пульсарів і джерел транзієнтного випромінювання. Описано стратегію та параметри огляду, характеристики обладнання, алгоритми обробки даних, а також попередні результати дослідження. Першим важливим результатом стало відкриття декаметрового випромінювання пульсара J0240+62. Тестові вимірювання показали, що чутливість, досяжна в цьому дослідженні, становить 5 Ян для транзієнтних сигналів та кілька міліянських для періодичного пульсарного випромінювання.В настоящее время на радиотелескопе УТР-2 проводится декаметровый обзор пульсаров и источников транзиентного излучения. Описана стратегия и параметры обзора, характеристики оборудования, алгоритмы обработки данных, а также предварительные результаты исследования. Первым важным результатом стало открытие декаметрового излучения пульсара J0240+62. Тестовые измерения показали, что чувствительность, достигаемая в настоящем исследовании, составляет 5 Ян для транзиентных сигналов и несколько миллиянских для периодического пульсарного излучения

Oscillation of the tunnel splitting in nanospin systems within the particle mapping formalism

The oscillation of tunnel splitting in the biaxial spin system within magnetic field along the anisotropy axis is analyzed within the particle mapping approach, rather than in the (\theta-\phi) spin coherent-state representation. In our mapping procedure, the spin system is transformed into a particle moving in the restricted $S^1$ geometry whose wave function subjects to the boundary condition involving additional phase shift. We obtain the new topological phase that plays the same role as the Wess-Zumino action in spin coherent-state representation. Considering the interference of two possible trajectories, instanton and anti-instanton, we get the identical condition for the field at which tunneling is quenched, with the previous result within spin coherent-state representation.Comment: 11 pages, 1 figure; Some typographical errors have been correcte

New decameter radiopolarimeter URAN-2

The description of the new decameter radiopolarimeter is submitted. It is created based on the phased array URAN-2, which is the greatest decameter array in the world after UTR-2, having the effective area about 30 000 m2, consisting of 512 broadband dipoles and working at frequencies from 10 up to 30 MHz. Polarimeter works at the central frequency of 24.75 MHz in a band of 10 kHz and 0.3 kHz. It provides reception of circular polarization waves by the horizontal crossed dipoles from any direction. Its sensitivity is ≈100 Jy. With the URAN-2 radiopolarimeter polarizing characteristics of a sporadic radio emission of the Sun (bursts of II and III types), and Jupiter (L- and S-bursts) are investigated. The obtained data will consist well with the results derived in adjacent frequency ranges. At research of the radio emission of Cyg A and Cas A the essential fluctuations of a degree of circular polarization (Stokes V parameter) of these sources radiations are found. This is caused, presumably, by ionosphere inhomogeneity. It is unique radiopolarimeter really working on so low frequencies. The URAN-2 radiopolarimeter organically supplements unique Ukrainian system of URAN decameter radio telescopes

Tunneling of quantum rotobreathers

We analyze the quantum properties of a system consisting of two nonlinearly coupled pendula. This non-integrable system exhibits two different symmetries: a permutational symmetry (permutation of the pendula) and another one related to the reversal of the total momentum of the system. Each of these symmetries is responsible for the existence of two kinds of quasi-degenerated states. At sufficiently high energy, pairs of symmetry-related states glue together to form quadruplets. We show that, starting from the anti-continuous limit, particular quadruplets allow us to construct quantum states whose properties are very similar to those of classical rotobreathers. By diagonalizing numerically the quantum Hamiltonian, we investigate their properties and show that such states are able to store the main part of the total energy on one of the pendula. Contrary to the classical situation, the coupling between pendula necessarily introduces a periodic exchange of energy between them with a frequency which is proportional to the energy splitting between quasi-degenerated states related to the permutation symmetry. This splitting may remain very small as the coupling strength increases and is a decreasing function of the pair energy. The energy may be therefore stored in one pendulum during a time period very long as compared to the inverse of the internal rotobreather frequency.Comment: 20 pages, 11 figures, REVTeX4 styl