Galkhaita

Los análisis de Gal-Khaya y Khaidarkan dieron, respectivamente, Hg 47,60, 49,02; Cu 3,49, 2,85; Zn 3,00, 0,60; Fe 0,31, nada ; Tl 0,46, 2,90; As 23,60, 19,49; Sb 0,59, 5,51; S 21,00, 19,31; Se 3 ppm, 150 ppm; total 100,05, 99,695 %.(...

Beam-helicity asymmetries for single-hadron production in semi-inclusive deep-inelastic scattering from unpolarized hydrogen and deuterium targets

A measurement of beam-helicity asymmetries for single-hadron production in deep-inelastic scattering is presented. Data from the scattering of 27.6 GeV electrons and positrons off gaseous hydrogen and deuterium targets were collected by the HERMES experiment. The asymmetries are presented separately as a function of the Bjorken scaling variable, the hadron transverse momentum, and the fractional energy for charged pions and kaons as well as for protons and anti-protons. These asymmetries are also presented as a function of the three aforementioned kinematic variables simultaneously

Transverse-target-spin asymmetry in exclusive ω\omega-meson electroproduction

Hard exclusive electroproduction of $\omega$ mesons is studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off a transversely polarized hydrogen target. The amplitudes of five azimuthal modulations of the single-spin asymmetry of the cross section with respect to the transverse proton polarization are measured. They are determined in the entire kinematic region as well as for two bins in photon virtuality and momentum transfer to the nucleon. Also, a separation of asymmetry amplitudes into longitudinal and transverse components is done. These results are compared to a phenomenological model that includes the pion pole contribution. Within this model, the data favor a positive $\pi\omega$ transition form factor.Comment: DESY Report 15-14

Epigenetic «probes» for lung cancer monitoring: LINE-1 methylation pattern in blood- circulating DNA

Malignant cell transformation is accompanied by two processes of DNA methylation changes: promoter hypermethylation of specific genes and hypomethylation of retrotransposons. The composition of circulating DNA (cirDNA) from plasma and cell-surface-bound circulating DNA (csb- cirDNA) was shown earlier to be altered in the blood of cancer patients due to accumulation of tumor- specific aberrantly methylated DNA fragments, which are currently considered valuable cancer markers. The present study compares LINE-1 retrotransposon methylation patterns in plasma cirDNA and csb- cirDNA from 21 untreated lung cancer patients (LC) and 23 healthy donors. Concentrations of methylated LINE-1 region 1 copies (LINE-1met) were assayed by real-time methylation-specific PCR. In order to normalize the LINE-1 methylation level, the LINE-1 region 2 concentration was evaluated, which was independent of the methylation status (LINE-1Ind). The LINE-1met concentration in csb-cirDNA tended to decrease (by a factor of 1.4) in blood from LC patients in comparison to healthy donors (Mann- Whitney test, P=0.16). The LINE-1Ind concentration in csb-cirDNA (methylation-independent) was found to be threefold lower in LC patients and fourfold lower in patients with adenocarcinoma than in healthy donors. That is why, along with the expected decrease in LINE-1met concentration in csb-cirDNA, we recorded an unexpected statistically significant increase of the LINE-1 methylation index determined as (LINE-1met/LINE-1Ind) due to the profound LINE-1Ind decrease. Plasma cirDNA demonstrated no difference in the LINE-1 methylation index (LINE-1met/LINE-1Ind) between LC patients and healthy donors (Mann-Whitney test, P = 0.40). The data obtained agree with our earlier results, which showed that csb-cirDNA was a highly informative material for lung cancer diagnostics

Longitudinal double-spin asymmetries in semi-inclusive deep-inelastic scattering of electrons and positrons by protons and deuterons

A comprehensive collection of results on longitudinal double-spin asymmetries is presented for charged pions and kaons produced in semi-inclusive deep-inelastic scattering of electrons and positrons on the proton and deuteron, based on the full HERMES data set. The dependence of the asymmetries on hadron transverse momentum and azimuthal angle extends the sensitivity to the flavor structure of the nucleon beyond the distribution functions accessible in the collinear framework. No strong dependence on those variables is observed. In addition, the hadron charge-difference asymmetry is presented, which under certain model assumptions provides access to the helicity distributions of valence quarks