Possibility of local pair existence in optimally doped SmFeAsO(1-x) in pseudogap regime

We report the analysis of pseudogap Delta* derived from resistivity experiments in FeAs-based superconductor SmFeAsO(0.85), having a critical temperature T_c = 55 K. Rather specific dependence Delta*(T) with two representative temperatures followed by a minimum at about 120 K was observed. Below T_s = 147 K, corresponding to the structural transition in SmFeAsO, Delta*(T) decreases linearly down to the temperature T_AFM = 133 K. This last peculiarity can likely be attributed to the antiferromagnetic (AFM) ordering of Fe spins. It is believed that the found behavior can be explained in terms of Machida, Nokura, and Matsubara (MNM) theory developed for the AFM superconductors.Comment: 5 pages, 2 figure

Incoherent pion photoproduction on the deuteron in the first resonance region

Incoherent pion photoproduction on the deuteron is studied in the first resonance region. The unpolarized cross section, the beam asymmetry, and the vector and tensor target asymmetries are calculated in the framework of a diagrammatic approach. Pole diagrams and one-loop diagrams with $NN$ scattering in the final state are taken into account. An elementary operator for pion photoproduction on the nucleon is taken in various on-shell forms and calculated using the SAID and MAID multipole analyses. Model dependence of the obtained results is discussed in some detail. A comparison with predictions of other works is given. Although a reasonable description of many available experimental data on the unpolarized total and differential cross sections and photon asymmetry has been achieved, in some cases a significant disagreement between the theory and experiment has been found. Invoking known information on the reactions $\gamma d\to\pi^0 d$ and $\gamma d\to np$ we predict the total photoabsorption cross section for deuterium. We find that our values strongly overestimate experimental data in the vicinity of the $\Delta$ peak.Comment: 22 pages, 23 figure

Phenotypic stability of spring bread wheat regenerant lines

Background. Selection of somaclonal variation under callus culture (СС) conditions is one of the methods of undirected genome change induction which has become actively used in the development of cultivars with high adaptive potential. The aim of the present study was the estimation of the applicability of dedifferentiated cell culture to obtain cultivars with different levels of phenotypic stability.Materials and methods. Ten wheat regenerant lines (RLs), obtained under selective (NaCl, low pH, drought) and nonselective conditions on the basis of СС were assessed along with their donor genotypes or the ones considered equivalent to them (in the case where the breeding variety was a donor) under field conditions on plots of 1 m2. 1000 grain weight data were used for the evaluation of the agronomic (bi, s2di) and biological (σ2САСi) stability. The yield-based superiority measure (Pi) was also calculated.Results. RLs from cv. ‘Novosibirskaya 15’ were more stable than their donor genotype from the biological viewpoint as well as from the agronomic one. The GGE-biplot analysis shows that they belong to the same “environment” (sector) with the vertex genotype ‘Novosibirskaya 15’ with bi being close to 1. Cv. ‘Tayozhnaya’ and its high-yielding salt tolerant RL RS(Tayozhnaya)3.6 were located in the opposite sectors and appeared to be highly stable genotypes. They are considered to be better adapted to low-yielding locations (bi < 0,7) along with the RZ(К-79-2)7.16 RL, selected for drought tolerance. The RLs from the high-yielding K-142-4 line showed a wide range of values of the stability parameters. They were better adapted to high-yielding locations than their reference genotype, cv. ‘Minusa’. Thus, its RL had a low stability of 1000 grain weight.Conclusion. Consequently, cell selection is a valuable source of breeding material that differs significantly in phenotypic stability both from the donor genotype and from other RLs, developed under CC of the same donor plant

Semiclassical correlators of three states with large S^5 charges in string theory in AdS_5 x S^5

We consider semiclassical computation of 3-point correlation functions of (BPS or non-BPS) string states represented by vertex operators carrying large charges in S5. We argue that the AdS5 part of the construction of relevant semiclassical solution involves the two basic ingredients: (i) configuration of three glued geodesics in AdS2 suggested by Klose and McLoughlin in arXiv:1106.0495 and (ii) a particular Schwarz-Christoffel map of the 3-geodesic solution in cylindrical (tau, sigma) domain into the complex plane with three marked points. This map is constructed using the expression for the AdS2 string stress tensor which is uniquely determined by the 3 scaling dimensions as noted by Janik and Wereszczynski in arXiv:1109.6262 (our solution, however, is different from theirs). We also find the S5 part of the solution and thus the full expression for the semiclassical part of the 3-point correlator for several examples: extremal and non-extremal correlators of BPS states and a particular correlator of "small" circular spinning strings in S3 part of S5. We demonstrate that for the BPS correlators the results agree with the large charge limit of the corresponding supergravity and free gauge theory expressions.Comment: 43 pages, 4 figures; v2: minor corrections; v3: comments added at the end of section 3 and in section 5; v4: minor corrections; v5: discussion in subsection 3.3 correcte