Multiple Scattering of Electromagnetic Waves by an Array of Parallel Gyrotropic Rods

We study multiple scattering of electromagnetic waves by an array of parallel gyrotropic circular rods and show that such an array can exhibit fairly unusual scattering properties and provide, under certain conditions, a giant enhancement of the scattered field. Among the scattering patterns of such an array at its resonant frequencies, the most amazing is the distribution of the total field in the form of a perfect self-similar structure of chessboard type. The scattering characteristics of the array are found to be essentially determined by the resonant properties of its gyrotropic elements and cannot be realized for arrays of nongyrotropic rods. It is expected that the results obtained can lead to a wide variety of practical applications.Comment: 5 pages, 6 figure

Indicators of Food Activity As Breeding Dairy Cattle Characteristics

The article presents the data of ethological studies on dairy cows of the Ayrshire breed of the second lactation under conditions of stall-tethered keeping in the spring. Animals with increased nutritional activity have milk yield per 305 days of lactation higher by 1662 kg (P> 0.999) compared with animals with reduced nutritional activity. The amount of milk fat in animals with increased food activity is 72.8 kg more (P> 0.999), and the total amount of milk protein is 47.8 kg more (P> 0.999) than in animals with reduced food activity. An increased index of food activity characterizes Ayrshire cows. Comparison of milk yields obtained from Ayrshire cows with milk yields of cows with reduced food activity leads to the establishment of the following results: there is a difference in milk yield for the first lactation of 1179 kg (P> 0.999), a difference in the amount of milk fat 53.2 kg (P> 0.99), and by the amount of milk protein – 36.4 kg (P> 0.99). Comparison of the total activity index led to the following results: the difference in milk yield per 305 days of lactation is 1386 kg (P> 0.999), in the amount of milk fat 61.3 kg (P> 0.999), milk protein 40.0 kg (P> 0.999). The highest correlation is observed between the index of food activity and milk productivity in ultra-active animals. In infra-passive cows, the correlation between the index of food activity and milk productivity is negative. Therefore, an effective means of increasing milk productivity is the selection of animals of Ayrshire breed by ethological individuality, taking into account indices of food, motor, and general activity. The studied indices of ethological activity are inherited by cows and can be effectively used in breeding and breeding with highly productive cattle of the Vologda selection

Indicators of Food Activity as Breeding Dairy Cattle Characteristics

The article presents the data of ethological studies on dairy cows of the Ayrshire breed of the second lactation under conditions of stall-tethered keeping in the spring. Animals with increased nutritional activity have milk yield per 305 days of lactation higher by 1662 kg (P> 0.999) compared with animals with reduced nutritional activity. The amount of milk fat in animals with increased food activity is 72.8 kg more (P> 0.999), and the total amount of milk protein is 47.8 kg more (P> 0.999) than in animals with reduced food activity. An increased index of food activity characterizes Ayrshire cows. Comparison of milk yields obtained from Ayrshire cows with milk yields of cows with reduced food activity leads to the establishment of the following results: there is a difference in milk yield for the first lactation of 1179 kg (P> 0.999), a difference in the amount of milk fat 53.2 kg (P> 0.99), and by the amount of milk protein – 36.4 kg (P> 0.99). Comparison of the total activity index led to the following results: the difference in milk yield per 305 days of lactation is 1386 kg (P> 0.999), in the amount of milk fat 61.3 kg (P> 0.999), milk protein 40.0 kg (P> 0.999). The highest correlation is observed between the index of food activity and milk productivity in ultra-active animals. In infra-passive cows, the correlation between the index of food activity and milk productivity is negative. Therefore, an effective means of increasing milk productivity is the selection of animals of Ayrshire breed by ethological individuality, taking into account indices of food, motor, and general activity. The studied indices of ethological activity are inherited by cows and can be effectively used in breeding and breeding with highly productive cattle of the Vologda selection

Experimental Biointegration of a Titanium Implant in Delayed Mandibular Reconstruction

Background: Mandibular reconstruction, after extensive resection of the mandible for the treatment of oral cancer, is a well-known procedure, however, relatively little is known about bone integration into the titanium implant after reconstruction with a temporary plastic implant. The main goal of this experimental study was to study the process of osseous integration into the titanium implant in an in vivo experiment following prior mandibular reconstruction with a temporary plastic implant. Materials and Methods: Four ewes initially underwent a partial one-sided resection of the mandible, with the formation of an approximately 3 × 1 cm defect. All of the subjects received reconstruction with an implantation of a plastic plate (3 cm). The plastic plate was removed and replaced by a titanium implant at 1, 3, 6, and 12 months, accordingly. Both plastic and titanium implants were made via 3D-printing technology and personalized modeling. A total of 6 months after titanium implantation, a histological evaluation of biointegration was performed. Results: All surgeries were uncomplicated. The integration of osseous tissue into the titanium implant was seen in all cases. Histologically, each case showed variable integration of dense fibrotic tissue with fibroblasts and non-mature bone tissue with a definitive layer of bone matrix with many osteoblasts on the periphery. The prior implantation of the plastic plate did not interfere with bone integration into the titanium implant. Conclusion: Preliminary results demonstrated that a temporary plastic implant for mandibular reconstruction does not interfere with the consequent osseous biointegration of a permanent titanium implant. This shows that temporary reconstruction is a safe solution when delayed mandibular reconstruction is required due to disease severity