Strain and Magnetic Field Induced Spin-Structure Transitions in Multiferroic BiFeO3.

The magnetic-field-dependent spin ordering of strained BiFeO3 films is determined using nuclear resonant scattering and Raman spectroscopy. The critical field required to destroy the cycloidal modulation of the Fe spins is found to be significantly lower than in the bulk, with appealing implications for field-controlled spintronic and magnonic devices.

[Seasonal dynamics of infecting ability of the flea Citellophilus tesquorum altaicus in the Tuva natural focus of the plague]. / Sezonnaia dinamika zarazhaiushchei sposobnosti blokhi Citellophilus tesquorum altaicus v Tuvinskom prirodnom ochage chumy.

The infecting ability of the fleas Citellophilus tesquorum altaicus loff, 1936, the main plague vectors in the Tuva natural focus, was experimentally studied in different periods of the epizootic season. Seasonal dynamics in the efficiency of infecting the long-tailed Siberian souslik with the plague causative agent through flea bites was noticed. Seasonal differences in infectivity of the "blocked" flea bites are revealed. An increase of infected experimental animals with a generalization of infection process in the period of epizooty activation in the natural focus was observed. A resistance of the long-tailed Siberian souslik to the plague agent infection through flea bites in the spring season was registered.

[Relationships of parasitic triad co-members in a Tuva natural plague focus: environmental and physiological aspects (experimental studies)]. / Ekologo-fiziologicheskie aspekty vzaimootnoshenii sochlenov parazitarnoi triady v tuvinskom prirodnom ochage chumy (po éksperimental'nym issledovaniiam).

Long-term experimental studies of the environmental and physiological aspects of relationships of parasitic triad co-members, performed in a Tuva natural plague, by using Citellophilus tesquorum altaicus fleas, their natural feeder--a long-tailed Siberian souslik (Citellus undulatus), and the Yersinia pestis strain I-3226 that is typical of the focus were analyzed. A complex of biotic (the environmental features of a causative agent, avector, and a carrier) and abiotic (air temperature and moisture, atmospheric pressure, and seasonal changes) factors that ensure the existence of the enzootic disease plague in this area has been shown to exert a considerable impact on the pattern of relationships of parasitic triad co-members.

[The survival of the causative agent of plaque in the long-tailed suslik from a Tuva natural focus in wintertime]. / O sokhranenii vobuditelia chumy u dlinnokhvostogo suslika iz Tuvinskogo prirodnogo ochaga v zimnii period.

The survival of the causative agent of plague in the long-tailed souslik in the Tuva natural focus in winter was experimentally studied. They were made in a special bunker laboratory just in the focus. The experimental conditions were close to the hygrothermal parameters of a long-tailed souslik's burrow. Inoculation and placement of the animals and fleas into the bunker were accomplished in the September to early October. The rodents and ectoparasites were examined after their hibernation in the late April to early May of the following year. The duration of the experiment was 7.5 months. It has been found that the long-tailed souslik can be infected with the causative agent of plague before hibernation through transmission. There were no cases of plague microbial infection through the bite of fleas in sousliks following hibernation. Low infection rates of the fleas hibernating with their host were notified. The causative agent was found to survive in the mummified carcasses of sousliks for 7.5 months (the follow-up period).

[The seasonal dynamics of blocking in the flea Citellophorus tesquorum altaicus from the Tuva natural plague focus]. / Sezonnaia dinamika blokoobrazovaniia u blokhi Citellophorus tesquorum altaicus iz Tuvinskogo prirodnogo ochaga chumy.

Seasonal changes in the frequency of block formation have been established in C. tesquorum altaicus from the Tuva natural plague [correction of plaque] focus. Distinctions have been observed in the blocking of fleas born in different calendar years. "Young" fleas born the current year block more frequently than old ones born the previous year.