RESUMEN
The adapted DIRAC experiment at the CERN PS accelerator observed for the first time long-lived hydrogenlike π^{+}π^{-} atoms, produced by protons hitting a beryllium target. A part of these atoms crossed the gap of 96 mm between the target and a 2.1 µm thick platinum foil, in which most of them dissociated. Analyzing the observed number of atomic pairs, n_{A}^{L}=436_{-61}^{+157}|_{tot}, the lifetime of the 2p state is found to be τ_{2p}=(0.45_{-0.30}^{+1.08}|_{tot})×10^{-11} s, not contradicting the corresponding QED 2p state lifetime τ_{2p}^{QED}=1.17×10^{-11} s. This lifetime value is three orders of magnitude larger than our previously measured value of the π^{+}π^{-} atom ground state lifetime τ=(3.15_{-0.26}^{+0.28}|_{tot})×10^{-15} s. Further studies of long-lived π^{+}π^{-} atoms will allow us to measure energy differences between p and s atomic states and so to discriminate between the isoscalar and isotensor ππ scattering lengths with the aim to check QCD predictions.
RESUMEN
The observation of hydrogenlike πK atoms, consisting of π^{-}K^{+} or π^{+}K^{-} mesons, is presented. The atoms are produced by 24 GeV/c protons from the CERN PS accelerator, interacting with platinum or nickel foil targets. The breakup (ionization) of πK atoms in the same targets yields characteristic πK pairs, called "atomic pairs," with small relative momenta Q in the pair center-of-mass system. The upgraded DIRAC experiment observed 349±62 such atomic πK pairs, corresponding to a signal of 5.6 standard deviations. This is the first statistically significant observation of the strange dimesonic πK atom.
RESUMEN
Focal destruction of the adenohypophysis by Nd:YAG laser does not destroy other structures of the hypothalamo-pituitary region. During reparative regeneration, the focus of coagulation necrosis after laser destruction of the adenohypophysis is replaced by cicatricial tissue. A method for surgical treatment of pituitary adenomas was developed. The efficiency, safety, and low traumatism of this method were confirmed in 87 patients.
Asunto(s)
Adenoma/cirugía , Terapia por Láser , Adenohipófisis/efectos de la radiación , Neoplasias Hipofisarias/cirugía , Animales , PerrosRESUMEN
"Models are developed for the dynamics of the age structure of the population of a region into which there are migration flows from other regions with different fertility coefficients. The model is explored in detail for a three-age-group population. A number of optimisation problems are formulated which can be used for various planning purposes."
