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A rapid and reliable identification of the country of origin of protected timbers is one of the measures for combating illegal logging. Mahogany (Swietenia macrophylla King) trees are distributed from Mexico to Bolivia and the Brazilian Amazon and are included in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Near-infrared spectroscopy (NIRS) has been proven to be a promising technique for calibration based and rapid species identification. There are only a few studies concerning the origin determination of mahogany wood. The present study is dedicated to trace back mahogany wood from Bolivia, Brazil, Guatemala, Mexico and Peru by means of two different handheld NIR spectrometers. The spectra were obtained directly from the wood samples, and soft independent modeling of class analogy (SIMCA) and partial least squares for discriminant analysis (PLS-DA) models were developed for data evaluation. The SIMCA model was efficient and 67–100% and 70–98% of the origins were identified based on the spectral ranges from 1595 to 2396 nm and 950 to 1650 nm, respectively. The best results were obtained by the PLS-DA approach, in which the efficiency rates (EFR) vary from 90 to 100% with both spectrometers. In summary, both instruments were highly effective and are suitable for preliminary identification of the country of origin for mahogany wood.

The γ rays following the β-decay of 53Fe were investigated with high resolution detectors. Two unreported weak transitions were detected at the energies 1177 ± 1 keV and 2305 ± 1 keV. Log ft values were determined and spin and parity assignments made. On the basis of the results attained, a new decay scheme was proposed. Comparison with theoretical calculations are made.

Elastic differential cross sections for scattering of photons with 145 keV and 317 keV were measured for Pb, W, Sn, Cd, Ag, Mo and Cu for angles from 5° to 40°. For measuring the strong energy dependence of the cross section at small angles, a well collimated beam (±0,5°) and a small detecting solid angle were used. For the energies and angles studied, agreement between experiment and form factor calculations is found. The results are compared with recent measurements of other authors, which found disagreement with form factor calculations

Seven previously unreported gamma rays in the decay of Mo91 g-s -were observed and had their energy and intensity measured. For Mo91m two new gamma rays were observed and the levels fed by its decay were identified with l=1 levels found by (He3, d) reaction.

The energies and relative intensities of the γ-radiation following the decay of the 4.45 min isomer of 118ln have been measured using a Ge(Li) detector. A total of sixteen γ-rays was observed of which six for the first time. A decay scheme ist presented and discussed; it incorporates fifteen of the observed transitions.

The y-transitions in 79Se following the decay of 79As were investigated with a Ge(Li) detector. Six previously unreported γ-transitions were observed and energy and intensity measurements on eleven γ-rays are reported. A new decay scheme is proposed which incorporates all the observed γ-rays. Results concerning the decay schemes of some isotopes of selenium (81 and 73) are also presented.

From the intensity of K x-rays produced by 662 keV photons the sum of the total cross sections of the photoelectric and Compton effects on this shell is obtained for the atoms with Z = 27, 29, 32, 41, 42 and 47. The contribution of the photoeffect is about 15% for Co(Z = 27), 50% for Mo (Z = 42) and 70% for Ag(Z = 47). Using theoretical cross section for the photoeffect the total Compton cross section on the K-shell is evaluated. The results agree with the free electron value.

Spectra of γ rays (higher than 0.3 MeV) following the β decay of Ir197 are measured with a Ge-Li detector (30 cm3). The existence of four new brandies to the Pt197 levels at 877.6 ± 0.3; 939.7±0.3; 1049.6±0.3; 1341.8±0.3 keV is proposed and lower limit log f t values are determined. Spin and parity (1/2, 3/2)+ are assigned to the ground state of Ir197. A new transition of 299.5 ± 0.2 keV was observed following the Pt197 (80 min) decay.