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Chemically -driven isothermal close space vapour transport was used to prepare pure MoO2 films which were eventually converted to MoO3 by annealing in air. According to temperaturedependent Raman measurements, the MoO2/MoO3 phase transformation was found to occur in the 225 -350 o C range; no other phases were detected during the transition. A clear change in composition and Raman spectra, as well as noticeable modifications of the band gap and the absorption coefficient confirmed the conversion from MoO2 to MoO3. An extensive characterization of films of both pure phases was carried out. In particular, a procedure was developed to determine the dispersion relation of the refractive index of MoO2 from the shift of the interference fringes the used SiO2/Si substrate. The obtained refractive index was corrected taking into account the porosity calculated from elastic backscattering spectrometry. The Debye temperature and the residual resistivity were extracted from the electrical resistivity temperature dependence using the Bloch -Grüneisen equation. MoO3 converted samples presented very high resistivity and a typical semiconducting behaviour. They also showed intense and broad luminescence spectra, which were deconvoluted considering several contributions; and its behaviour with temperature was examined. Furthermore, surface photovoltage spectra were taken and the relation of these spectra with the photoluminescence is discussed.

We present an implementaion of the Feshbach formalism to calculate energy positions and widths of doubly excited states of Be-like ions. These systems can be treated formally as two-electron problems by using a suitable model potential to describe the effect of the 1s' core. In this respect, we discuss the pertinence of using the one-parameter model potential V =2r ' -2r '(1+ar)e Energies and widths for 1s 414l' 'S' and 'P' autoionizing states of N'+ and Ne + are reported.

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The number of pregnancies affected by neural tube defects has been estimated to be 4000/year in Europe, with a higher prevalence in Celtic populations and in women of low socioeconomic status. Since the 1980s, it has been shown that supplementation with folic acid during the periconceptual period reduces the risk of neural tube defects in the fetus. However, in view of the period during which supplementation should be taken (< 4 weeks before conception until 8-10 weeks after) and the fact that in some countries 30-50% of pregnancies are unplanned, a public health initiative based solely on increasing dietary folate intake or recommendations on use of folic acid supplements is likely to be insufficient. Mandatory fortification has been started in 38 countries throughout the world. Several European countries have advocated mandatory flour folic acid fortification over the last 6 years, but none has introduced it. A recent public health decision in Hungary stimulated flour fortification on a voluntary basis, but it remains the only European country to take this action. Many European countries have deferred a decision to introduce fortification because of concerns about possible masking of vitamin B (12) deficiency. This review advocates a proposal for combined fortification of folic acid and vitamin B (12) to address possible hazards of fortification with folic acid alone.