Numerical simulation of stratospheric QBO impact on the planetary waves up to the thermosphere.

With the help of numerical simulation, a detailed analysis of the dynamical effect of the stratospheric quasi-biennial oscillation (QBO) of the equatorial zonal wind on the planetary waves (PWs) up to thermospheric heights is carried out for the first time. The 3-dimensional nonlinear mechanistic model of middle and upper atmosphere (MUAM) is used, which is capable of simulating the general atmospheric circulation from the surface up to 300-400 km altitude. The amplitudes of stationary and westward travelling PWs with periods from 4 to 10 days are calculated based on ensembles of model simulations for conditions corresponding to the easterly and westerly QBO phases. Fluxes of wave activity and refractive indices of the atmosphere are calculated to analyze the detailed behavior of the PWs. The important result to emerge is that the stratospheric QBO causes statistically significant changes in the amplitudes of individual wave components up to 25% in the mesosphere-lower thermosphere and 10% changes above 200 km. This change in wave structures should be especially noticeable in the atmosphere during periods of low solar activity, when the direct contribution of solar activity fluctuations is minimized. Propagating from the troposphere to the upper atmosphere, PWs contribute to the propagation of the QBO signal not only from the equatorial region to extratropical latitudes, but also from the stratosphere to the thermosphere. The need for a detailed analysis of large-scale wave disturbances in the upper atmosphere and their relationship with the underlying layers is due, in particular, to their significant impact on satellite navigation and communication systems, which is caused by amplitude and phase fluctuations of the radio signal.

Fundamental crystal field excitations in magnetic semiconductor SnO2: Mn, Fe, Co, Ni.

Directly measuring elementary electronic excitations in dopant 3d metals is essential to understanding how they function as part of their host material. Through calculated crystal field splittings of the 3d electron band it is shown how transition metals Mn, Fe, Co, and Ni are incorporated into SnO2. The crystal field splittings are compared to resonant inelastic X-ray scattering (RIXS) experiments, which measure precisely these elementary dd excitations. The origin of spectral features can be determined and identified via this comparison, leading to an increased understanding of how such dopant metals situate themselves in, and modify the host's electronic and magnetic properties; and also how each element differs when incorporated into other semiconducting materials. We found that oxygen vacancy formation must not occur at nearest neighbour sites to metal atoms, but instead must reside at least two coordination spheres beyond. The coordination of the dopants within the host can then be explicitly related to the d-electron configurations and energies. This approach facilitates an understanding of the essential link between local crystal coordination and electronic/magnetic properties.

Bulk vs. Surface Structure of 3d Metal Impurities in Topological Insulator Bi2Te3.

Topological insulators have become one of the most prominent research topics in materials science in recent years. Specifically, Bi2Te3 is one of the most promising for technological applications due to its conductive surface states and insulating bulk properties. Herein, we contrast the bulk and surface structural environments of dopant ions Cr, Mn, Fe, Co, Ni, and Cu in Bi2Te3 thin films in order to further elucidate this compound. Our measurements show the preferred oxidation state and surrounding crystal environment of each 3d-metal atomic species, and how they are incorporated into Bi2Te3. We show that in each case there is a unique interplay between structural environments, and that it is highly dependant on the dopant atom. Mn impurities in Bi2Te3 purely substitute into Bi sites in a 2+ oxidation state. Cr atoms seem only to reside on the surface and are effectively not able to be absorbed into the bulk. Whereas for Co and Ni, an array of substitutional, interstitial, and metallic configurations occur. Considering the relatively heavy Cu atoms, metallic clusters are highly favourable. The situation with Fe is even more complex, displaying a mix of oxidation states that differ greatly between the surface and bulk environments.

Structural ordering in a silica glass matrix under Mn ion implantation.

Mn(+)-implanted, amorphous SiO(2) samples were synthesized using pulsed-ion implantation without thermal annealing. The crystal and electronic structures have been studied using x-ray diffraction and synchrotron-based soft x-ray absorption and emission spectroscopy at the Si and Mn L(2,3) edges. We find a combination of small MnO clusters and Si crystallites at shallow depths while tetrahedral Mn coordination is found deeper in the host target. Through a combination of techniques, we find that the implantation process simultaneously decreases the long-range order in the near-surface region and increases order deeper in the SiO(2) host. Our results suggest Mn substitution into Si sites at deep levels catalyzes the formation of α-quartz, providing insight into the complex interactions that determine the local structure around the impurities as well as the overall changes to the crystallinity of implanted SiO(2).

[Thymectomy for myastenia gravis: 25-year experience]. / Timektomiia za miasteniia gravis: 25-godishen opit.

OBJECTIVE: Thymectomy is considered an effective therapeutic option for patients with myasthenia gravis (MG). We reviewed our 25-years experience with surgical treatment of MG with respect to long-term results and factors affecting outcome. METHODS: Between 1978 and 2002, we performed 232 thymectomies for MG. Fifteen patients were lost to follow-up; the remaining 217 form the object of our study. 32 patients (28.4%) had thymoma. Myasthenia was graded according to a modified Osserman classification: 51 patients (23.5%) were in class I, 81 (37.3%) in class IIA, 52 (24%) in class IIB, 26 (12%) in class III and seven (3.2%) in class IV. Mean duration of symptoms before the operation was 14 +/- 10 months. Fifty-eight thymectomies for thymoma were performed through a median sternotomy and four through a clamshell incision. Forty-six thymectomies for non-thymomatous MG were performed through a standard cervicotomy, 155 procedures through a partial upper sternal-splitting incision and eight through a complete median sternotomy. RESULTS: Operative mortality was 0.92% (two patients). After a mean follow-up of 119 months, 77% of all patients improved their clinical status (26% without medications and asymptomatic; 45% with a reduction of medications and/or clinically improved); 39 (18%) have a stable disease with no clinical modifications; 12 (5%) presented a deterioration of their clinical status with worse symptoms, required more medications, or both. Thirteen patients (6%) died because of MG (mean survival 34.3 +/- 3.6 months). The presence of a thymoma negatively influenced the prognosis. Younger patients showed a more favorable outcome as well as patients with a shorter duration of symptoms before the operation; patients with lower classes of myasthenia showed a higher rate of remission. CONCLUSIONS: Thymectomy is effective in the management of patients with MG at all stages with low morbidity. Patients with thymoma present a less favorable outcome.

Commissioning of the accelerator-recuperator for the FEL at the Siberian Center for Photochemical Research.

A 100 MeV eight-turn accelerator-recuperator intended to drive a high-power infrared free-electron laser (FEL) is currently under construction in Novosibirsk. The first stage of the machine includes a one-turn accelerator-recuperator that contains a full-scale RF system. It was commissioned successfully in June 2002.

[Experimental studies on a decrease in hypotrophy in newborn piglets in commercial swine raising]. / Eksperimentalni prouchvaniia za namaliavane na khipotrofiiata pri novorodeni praseta v usloviia na promishlenoto svinevudstvo.

The birth of hypotrophic piglets with 2-3 times lower live weight than the normally born ones, which die till the 40th hour, because of the abruptly decreased vitality is described. Their percent is 7 for the reproductive bases and 10 for a commodity swine breeding complex. Studies were carried out on 402 pregnant pigs, treated with protein hydrolysate and glucose (injected) together with vitamin-mineral additions to the forage. For a control were used 395 pregnant pigs under the same conditions, but not treated with the above mentioned medicines. A two fold decrease of the birth of hypotrophic piglets was achieved. The rest of the pigs are with a higher live weight and vitality which is the reason of their suffering from coli bacteriosis and other diseases of the conditions at a considerably lower extent. It is supposed that the irreplaceable (limited) amino acids are at the base of that biological phenomena for the prophylaxis of the hypotrophy in the pathology of the hybrid industrial swine breeding. That model scheme as a method can be realized in reproductive and nuclear bases for hybrid swine breeding because of its undeniably great and economic effect.

[Multicausality in the pathology of commercial swine breeding]. / Multikauzalnost v patologiiata na promishlenoto svinevudstvo.

Studied were more than 100,000 samples of pathologic tissue material, 1,900 whole blood and blood serum samples, 8,000 fecal samples, 2,600 washings samples, swab samples, and other sampled material via the employment of a number of bacteriologic, virologic, morphologic, hematologic, biochemical, parasitologic, and other routinely applicable laboratory methods over a period of 5 years. All materials were taken from 15 stock swine breeding complexes, 3 reproduction and 2 nucleus bases for hybrid pigs, and 3 swine breeding farms with a practice of extensive raising technology. It was demonstrated that the adaptive capacity of the animals of the Camborough hybrid sharply dropped when the pigs were kept under unconventional conditions of raising, leading to deviations in the application of industrial technology methods. This was the reason to observe the simultaneous manifestation of conditionally substantiated disease outbreaks (multiple causality), with great economic losses. Studied were the etiology and pathogenesis of coli bacteriosis, salmonellosis, gastric ulcer, hypotrophy, atrophic rhinitis, geohelminthiases, chlamydial infections, and erysipelas. Suggested is the use of programmes and methods of prophylaxis and treatment, of expedient diagnosis and control on immunity.

[Commercial method of aerogenic immunization of pigs against swine fever]. / Promishlen metod ze aerogenno imunizirane na praseta protiv chuma.

An industrial method is presented through a model with a chamber for aerogenic immunization of about 250 pigs, aged 2.5 months. The experiments were carried out with more than 1,000 pigs of the Camborough hybrid under industrial conditions of raising. The process of immunization was feasibly carried out when the pigs passed through the chamber using aerosol at mixing them upon transference from the growing section to the fattening one, according to the provisions of the raising technology. A lapinized K-vaccine against fever, obtained from rabbits or tissue cultures was used in a dispersed state. Essential proved the high titer of the vaccine. Used were the aerosol devices DAG-2 or Microjet Fogmaster mounted at 1.5 m above the chamber floor. They guarantee the production of highly dispersed aerosol of an average arithmetic size of 7-10 microns, its concentration reaching 3,000,000 particles per 1 cm3. The animals were exposed for 30 min with Fogmaster and 45 min with DAG-2. It was shown that they tolerated perfectly this group immunization. A single procedure with the vaccine conferred immunity at 2.10(5) LT50 and protected the pigs from fever over the entire fattening period. The method was evaluated as a biotechnology.

[Pathology in hybrid pig breeding due to mixed infections]. / Patologiia na khibridnoto svinevudstvo, prichineno ot smeseni infektsii.

A total of 7,500 samples from 5 swine breeding complexes with 200,000 hybrid Camborough pigs were studied morphologically and bacteriologically. The raising technologies used on all complexes were of industrial type or semi-industrial and extensive. A description is given of the simultaneous participation of the following nosologic units: colibacteriosis, responsible for 13 to 14 per cent of the total mortality rate in newborn pigs; bronchopneumonia--causing 6 to 39 per cent losses in the other age groups; and dysentery with salmonellosis--inflicting 5 to 9 per cent losses. Underlined is the great advantage of the industrial technologies of animal raising as against the conventional ones in the prevention of these diseases in hybrid pig breeding. Tested were effective programmes for the prophylaxis associated with the individual nosologic units. More essential were the following: active immunoprophylaxis with live attenuated vaccines against colibacteriosis and salmonellosis; elimination of the alimentary stress factor in dysentery; disinfections of premises by gassing with a mixture of ammonium nitrate and chlorinated lime in a 1:2 ratio. However, all measures proved effective when the principle of "all in, all out' was observed which is essential part of the Camborough industrial raising technologies.

[Reproduction of salmonellosis in swine by aerosol infection]. / Vuzproizvezhdane na salmonelloza po svinete chrez aerozolno zaraziavane.

Four 36-day-old pigs were infected through aerosol with Salmonella cholerae suis var. america, and one pig was injected with same pathogen intravenously as a control, all animals being treated in a chamber. The temperature and the other clinical signs were followed up. Rectal samples and hemocultures were investigated for Salmonella organisms. On the 4th, 8h, 14th, and 25th day a pig was killed for bacteriologic and histopathologic investigations of the viscera. As early as the 48th hour there were in the aerosol-treated animals a rise of temperature and deterioration of the general status. From those that were killed at varying intervals Salmonellae were isolated from the lungs, mediastinal lymph nodes, small intestines, and other organs up to the 14th day after the pigs were infected, while on the 25th day Salmonellae were recovered only in the caecum, from the rectal samples of 3 pigs, and in a hemoculture from one pig. Histopathologically, there were lesions characteristic of salmonellosis. It is supposed that in the conditions of industrial pig farming at least two mechanisms of transmitting the Salmonella organisms exist -- the alimentary one (a primary route), and the air dust one.

[Use of lapinized "C" vaccine as aerosol in immunoprophylaxis against swine fever]. / Anwendung der lapinisierten "C"-Vakzine als Aerosol bei der Immunprophylaxe der Schweinepest.

Lapinised vaccine, strain "C", was used on 3500 fattening pigs on two farms in experiments for aerogenic immunisation. Two ordinary pigsties were modified for use as aerosol application chambers. A USSR-made disc-type aerosol generator, DAG-2, was used for vaccine dispersion. Piglets were allowed to be in contact with the aerosolic vaccine antigen for about 60 minutes. No deterioration in general health condition was observed, when longer contact periods were allowed. Existing respiratory disorders did not aggravate. Immunity was obtained seven or eight days from the time of aerosolic immunisation and lasted not less than ten months. The prospects of such groupwise immunisation of pigs against swine fever under conditions of industrialised rearing are discussed against the background of epizootiological and economic aspects. The results so far obtained from aerogenic immunisation form a good basis for its further development and eventual use under conditions of industrialised swine keeping.