Triangle Singularity as the Origin of the a_{1}(1420).

The COMPASS Collaboration experiment recently discovered a new isovector resonancelike signal with axial-vector quantum numbers, the a_{1}(1420), decaying to f_{0}(980)π. With a mass too close to and a width smaller than the axial-vector ground state a_{1}(1260), it was immediately interpreted as a new light exotic meson, similar to the X, Y, Z states in the hidden-charm sector. We show that a resonancelike signal fully matching the experimental data is produced by the decay of the a_{1}(1260) resonance into K^{*}(→Kπ)K[over ¯] and subsequent rescattering through a triangle singularity into the coupled f_{0}(980)π channel.

First Measurement of Transverse-Spin-Dependent Azimuthal Asymmetries in the Drell-Yan Process.

The first measurement of transverse-spin-dependent azimuthal asymmetries in the pion-induced Drell-Yan (DY) process is reported. We use the CERN SPS 190  GeV/c π^{-} beam and a transversely polarized ammonia target. Three azimuthal asymmetries giving access to different transverse-momentum-dependent (TMD) parton distribution functions (PDFs) are extracted using dimuon events with invariant mass between 4.

Initial experience with gamma knife radiosurgery for advanced glaucoma.

Object: The authors assessed the affect of gamma knife radiosurgery on patients with glaucoma.

Methods: Fifteen eyes in 14 patients were treated with gamma knife radiosurgery during a 14-month period. Ocular pain was alleviated in all patients and intraocular pressure was decreased.

[The first year of use of the Leksell gamma knife at the Hospital Na Homolce--results after 5 years].

The first Leksell gamma knife procedure was performed in Prague on 26th October 1992 and during the first year 156 patients were treated at the department of stereotactic and radiation neurosurgery. 42% patients suffered from a vascular lesion, 39% of patients from a benign tumour and 19% patients from a malignant tumour. Radiosurgery using the gamma knife is a non-invasive stereotactic neurosurgical procedure.

[Use of the radiosurgery knife in the treatment of hypophyseal adenomas].

BACKGROUND. Surgery of pituitary adenomas did not produce quite satisfactory results. Therefore radiosurgery using Leksell's gamma knife has become the most widely used method which-with the contribution of MRI-meets the most important demands of aimed irradiation: a sufficiently high dose of radiation of the tumour and minimal radiation load of functionally important surrounding structures.