Cyanocobalamin in mycelium of Neurospora sitophila

Cyonocobolamine in N. sitophil

Changes in chemical composition of N. sitophila during the active growth phase

Changes in chemical composition during growt

A New Versatile System for Freeze-Substitution, Freeze-Drying and Low Temperature Embedding of Biological Specimens

A universal system for freeze-substitution (FS), freeze-drying (FD) and low temperature embedding (LTE) has been developed, suited to perform standardized procedures of cryoprocessing biological and medical specimens as well as systematic studies of dehydration and embedding at various low and high temperatures. In a 35 I Dewar vessel with 110 mm neck diameter an aluminum tube is mounted to the bottom of the liquid nitrogen (LN2x) reservoir and extends to the lower part of the cylindrical neck. At its top an aluminum plate serves as a contact surface for either the FS chamber or the FD chamber. FS and subsequent LTE are carried out in an environment of dry cold nitrogen gas provided by evaporating nitrogen from the dewar. Different capsules and moulds may be used for cryodehydration and LTE. FD of bulk specimens or cryosections takes place in an absolutely clean vacuum provided by a cryosorption pump integrated in the FD apparatus. Most of the Hp molecules from the frozen specimen are trapped by large cold surfaces inside the drying chamber. Due to the low LN2 consumption during FS or FD (3-4 l LN2/day) both procedures may be carried out for 8-10 days without refilling the dewar. A few representative results show that well frozen biological material is stabilized by prolonged FS or FD at temperatures of about -80°C without use of chemical fixatives like OsO4 in the substitution medium during FS or by OsO4 vapor fixation after FD

Міфологізм у символістській прозі Клима Поліщука

The particularities of mythology in symbolist prose by Klym Polishchuk are explained in the article. There are two time planes of plot evolvement in fantastic stories by Klym PolishchukG past and present. Fantastic events in the past have continuation in

Inclusive K^+ meson production in proton-nucleus interactions

The production of K^+ mesons in pA (A = D, C, Cu, Ag, Au) collisions has been investigated at the COoler SYnchrotron COSY-J\"ulich for beam energies T_p = 1.0 - 2.3 GeV. Double differential inclusive pC cross sections at forward angles theta < 12 degrees as well as the target-mass dependence of the K^+ momentum spectra have been measured with the ANKE spectrometer. Far below the free NN threshold at T_{NN}=1.58 GeV the spectra reveal a high degree of collectivity in the target nucleus. From the target-mass dependence of the cross sections at higher energies, the repulsive in-medium potential of K^+ mesons can be deduced. Using pN cross-section parameterisations from literature and our measured pD data we derive a cross-section ratio of sigma(pn -> K^+ X) / sigma(pp -> K^+ X) ~ (3-4).Comment: Accepted for publication in EPJ A; 17 pages, 10 figures, 11 table

Evidence of kaon nuclear and Coulomb potential effects on soft K+ production from nuclei

The ratio of forward K+ production on copper, silver and gold targets to that on carbon has been measured at proton beam energies between 1.5 and 2.3 GeV as a function of the kaon momentum p_K using the ANKE spectrometer at COSY-Juelich. The strong suppression in the ratios observed for p_K<200-250 MeV/c can be ascribed to a combination of Coulomb and nuclear repulsion in the K+A system. This opens a new way to investigate the interaction of K+-mesons in the nuclear medium. Our data are consistent with a K+A nuclear potential of V_K~20 MeV at low kaon momenta and normal nuclear density. Given the sensitivity of the data to the kaon potential, the current experimental precision might allow one to determine V_K to better than 3 MeV.Comment: 9 pages, 3 figures; changed conten

Evidence for an Excited Hyperon State in pp -> p K^+ Y^{0*}

Indications for the production of a neutral excited hyperon in the reaction pp -> p K^+ Y^{0*} are observed in an experiment performed with the ANKE spectrometer at COSY-J\"ulich at a beam momentum of 3.65 GeV/c. Two final states were investigated simultaneously, viz. Y^{0*} -> pi^+X^- and pi^-X^+, and consistent results were obtained in spite of the quite different experimental conditions. The parameters of the hyperon state are M(Y^{0*})= (1480 +/- 15) MeV/c^2 and Gamma(Y^{0*})= (60 +/- 15) MeV/c^2. The production cross section is of the order of few hundred nanobarns. Since the isospin of the Y^{0*} has not been determined here, it could either be an observation of the Sigma(1480), a one-star resonance of the PDG tables, or alternatively a Lambda hyperon. Relativistic quark models for the baryon spectrum do not predict any excited hyperon in this mass range and so the Y^{0*} may be of exotic nature.Comment: 4 pages, 3 figures, accepted for publication in Phys.Rev.Let

CARBON BALANCE AND VEGETATION DYNAMICS IN AN OLD‐GROWTH AMAZONIAN FOREST

Amazon forests could be globally significant sinks or sources for atmospheric carbon dioxide, but carbon balance of these forests remains poorly quantified. We surveyed 19.75 ha along four 1‐km transects of well‐drained old‐growth upland forest in the Tapajós National Forest near Santarém, Pará, Brazil (2°51′ S, 54°58′ W) in order to assess carbon pool sizes, fluxes, and climatic controls on carbon balance. In 1999 there were, on average, 470 live trees per hectare with diameter at breast height (dbh) ≥10 cm. The mean (and 95% ci) aboveground live biomass was 143.7 ± 5.4 Mg C/ha, with an additional 48.0 ± 5.2 Mg C/ha of coarse woody debris (CWD). The increase of live wood biomass after two years was 1.40 ± 0.62 Mg C·ha−1·yr−1, the net result of growth (3.18 ± 0.20 Mg C·ha−1·yr−1 from mean bole increment of 0.36 cm/yr), recruitment of new trees (0.63 ± 0.09 Mg C·ha−1·yr−1, reflecting a notably high stem recruitment rate of 4.8 ± 0.9%), and mortality (−2.41 ± 0.53 Mg C·ha−1·yr−1 from stem death of 1.7% yr−1). The gain in live wood biomass was exceeded by respiration losses from CWD, resulting in an overall estimated net loss from total aboveground biomass of 1.9 ± 1.0 Mg C·ha−1·yr−1. The presence of large CWD pools, high recruitment rate, and net accumulation of small‐tree biomass, suggest that a period of high mortality preceded the initiation of this study, possibly triggered by the strong El Niño Southern Oscillation events of the 1990s. Transfer of carbon between live and dead biomass pools appears to have led to substantial increases in the pool of CWD, causing the observed net carbon release. The data show that biometric studies of tropical forests neglecting CWD are unlikely to accurately determine carbon balance. Furthermore, the hypothesized sequestration flux from CO2 fertilization (\u3c0.5 Mg C·ha−1·yr−1) would be comparatively small and masked for considerable periods by climate‐driven shifts in forest structure and associated carbon balance in tropical forests