Interaction and collision of skyrmions in chiral antiferromagnets

Skyrmions in an antiferromagnet can travel as solitary waves in stark contrast to the situation in ferromagnets. Traveling skyrmion solutions have been found numerically in chiral antiferromagnets. We consider head-on collision events between two skyrmions. We find that the result of the collision depends on the initial velocity of the skyrmions. For small velocities, the skyrmions are shrinking as they are approaching, they bounce back and eventually acquire almost their initial speed. For larger velocities, the skyrmions approach each other and shrink until they become singular points and are eventually annihilated. We describe the observed phenomena in terms of skyrmion energetics and thus determine the regimes of the different dynamical behaviors

Tusk Paleohistology as a tool in the discrimination of fossil tusks from Greece

En aquest estudi intentam discriminar entre les defenses de Mammuthus meridionalis, Elephas antiquus i les dels elefants nans de l'illa de Tilos, en base a les característiques histològiques de la dentina. El tret mesoscòpic examinat és el Patró d'Schreger, en relació a l'angle, -la longitud d'ona i l'aparença qualitativa, i els trets microscòpics són la mida dels túbuls de dentina i la seva densitat. Les mostres de defenses de mamut es diferencien clarament de les d'elefants. A més, trobam una petita variança en l'aparença qualitativa del Patró d'Schreger entre les mostres d' Elephas antiquus i les defenses dels elefants nans. Finalment, la mida dels túbuls de dentina de les defenses dels elefants endèmics és, clarament, la major.In the current study, we have attempted to distinguish between the tusks of Mamrnuthus meridionalis, Eiephas antiquus and the dwarf elephants from the island ofTilas, based on the tusk dentine's histological characteristics. The mesoscopic feature examined is the Schreger Pattern, in respect to its angle, wavelength and qualitative appearance, and the microscopic features are the dentinal tubule's size and density. The mammoth samples strongly discriminate against the elephant tusks. In addition, we were able to find a small variance in the Schreger Pattern's qualitative appearance, between the samples of Elephas antiquus and the tusks of the dwarfs. Finally, the size of the dentinal tubules is clearly greatest in the tusks of the endemic elephants

Effect of dietary protein source on piglet meat quality characteristics

An experiment was conducted to examine the effects of different dietary protein sources (soybean meal vs whey protein) on piglet meat quality characteristics. Eighteen castrated male Large White × Duroc × Landrace piglets were randomly assigned to 2 groups. Piglets were kept in individual metabolic cages and fed ad libitum over a period of 38 days the following 2 diets: diet SB, which was formulated to meet the nutrient requirements of piglets using soybean meal as the main crude protein source and diet WP, where SB was totally replaced by a mixture of whey proteins on equal digestible energy and crude protein basis. At the end of the experiment, piglets were weighed and slaughtered. After overnight chilling, samples of Longissimus dorsi muscle were taken and were used for meat quality measurements.         No significant differences were observed in the values of pH, colour, water holding capacity, shear force and intramuscular fat content of L. dorsi muscle between the dietary treatments. Measurement of lipid oxidation values showed that dietary supplementation with different protein sources did not influence meat antioxidant properties during refrigerated storage. The SB piglets had lower 14:0 (P<0.01) and higher 18:3n-3 (P<0.001) levels in intramuscular fat in comparison with WP piglets. However, these changes were attributed to background differences in the dietary FA profile and not to a direct protein source effect. The results of this preliminary study indicate that the examined dietary protein sources (soybean meal or whey protein) do not have a significant effect on meat quality characteristics of piglets