Time-reversal symmetry breaking versus superstructure

One of the mysteries of modern condenced-matter physics is the nature of the pseudogap state of the superconducting cuprates. Kaminski et al.1 claimed to have observed signatures of time-reversal symmetry breaking in the pseudogap regime in underdoped Bi2Sr2CaCu2O8+d (Bi2212). Here we argue that the observed dichroism is due to the 5x1 superstructure replica of the electronic bands and therefore cannot be considered as evidence for the spontaneous time-reversal symmetry breaking in cuprates.Comment: 5 pages, pd

TaIrTe4 a ternary Type-II Weyl semi-metal

In metallic condensed matter systems two different types of Weyl fermions can in principle emerge, with either a vanishing (type-I) or with a finite (type-II) density of states at the Weyl node energy. So far only WTe2 and MoTe2 were predicted to be type-II Weyl semi-metals. Here we identify TaIrTe4 as a third member of this family of topological semi-metals. TaIrTe4 has the attractive feature that it hosts only four well-separated Weyl points, the minimum imposed by symmetry. Moreover, the resulting topological surface states - Fermi arcs connecting Weyl nodes of opposite chirality - extend to about 1/3 of the surface Brillouin zone. This large momentum-space separation is very favorable for detecting the Fermi arcs spectroscopically and in transport experiments

Selection and Breeding of Dairy Cattle in Western Siberia

The main objective of stock breeding is to raise highly productive animals, improve existing ones and create new types and breeds of livestock. The main focus of dairy cattle breeding is on increasing milk yield, fat and protein content in milk; preserving fertility and productive longevity; and developing high adaptive properties of suitability for modern industrial technologies. Selection and breeding of black-and-white and red steppe breeds of cattle is aimed at improving the breeding and productive qualities of the animals. These breeds are traditionally raised in Western Siberia. Breeding to improve the economic and productive features of black-and-white and red steppe breeds of cattle led to the creation of new zonal types, including the Priobsky, Kulunda and Siberian zonal types, which are characterized by relatively high dairy productivity. This study showed that the Siberian type of heifers had the maximum milk yield – 6389 kg, which was 1239 kg and 828 kg more than the Kulunda and Priobsky types, respectively. The same tendency was observed for the third lactation. Animals with a dry period of less than 40 days had lower milk yields than those with a longer period. In terms of the amount of milk and the weight fraction of fat and protein in the milk, the animals exceeded the standard for the parental breed. The duration of pregnancy among the studied animals was within the physiological norm – 276.1-280.8 days. The research results may be of interest to agricultural students and specialists involved in selection issues. Keywords: reproduction, breed, milk productivit