Abstract. We investigate the radiation processes inside supernova remnants which are powered by young pulsars. Using a recent model for particle acceleration by the pulsar wind nebulae (PWNe), in which positrons gain energy in the process of resonant scattering by the heavy nuclei, we construct a time-dependent radiation model for the PWNe. In this model, the spectra of relativistic particles, injected inside the nebula, depend on time due to the evolution of the pulsar parameters. Applying a simple model for the evolution of the PWNa, the equilibrium spectra of leptons and nuclei inside the nebula are determined as a function of time, taking into account the energy losses of particles on different processes and their escape from the nebula. We calculate the multiwavelength photon spectra produced by leptons and nuclei and compare them with the observations of the PWNe for which TeV γ-ray emission has been reported, i.e. the Crab Nebula, the Vela Supernova Remnant, and the nebula around PSR 1706-44. It is found that the emission from the Crab Nebula can be well fitted by the composition of the γ-ray emission produced by leptons (below ∼10 TeV) and nuclei (∼10 TeV). The model is further tested by successful fitting of the high energy spectrum from the Vela SNR. In this case, the observed γ-ray emission is mainly due to leptons and the contribution of γ-rays from decay of neutral pions, produced in collision of nuclei, is significantly lower. However, the considered model does not give good fitting to the emission from PSR1706-44 for the likely parameters of this source, unless an additional target for relativistic leptons is present inside the nebula, e.g. the thermal infrared emission. Based on the knowledge obtained from these fittings, we predict the γ-ray fluxes in the TeV energy range from other PWNe, which are promissing TeV γ-ray sources due to their similarities to the γ-ray nebulae, i.e. MSH15-52 (PSR 1509-58), 3C58 (PSR J0205+6449), and CTB80 (PSR 1951+32). Possible detection of these sources by the new generation of Cherenkov telescopes is discussed.

Exposure to mycotoxins may be associated with carcinogenic, immunosuppressant and estrogenic effects. In the Middle-East, studies investigating food contamination and dietary exposure to mycotoxins are particularly scarce. This study aims at evaluating the dietary exposure of an adult Lebanese urban population to four mycotoxins (AFB1, AFM1, OTA, DON) classified as priority food contaminants by the WHO. Dietary exposure assessment was performed by means of the total diet study approach. Average and excessive consumer exposure estimates (p95) were calculated and compared with appropriate toxicological reference values (TRVs). Average dietary exposure levels to OTA and DON represented 29.9% and 156.8% of the respective TRVs, with the p95 exposure estimates approaching or exceeding the TRVs for these mycotoxins (95.1% and 355.8%, respectively). Based on the mean dietary exposure level to AFB1, cancer risk was estimated at 0.0527-0.0545cases/100,000persons/year, while mean exposure to AFM1 was associated with a population risk of 0.0018-0.0027cases/100,000persons/year. The study's findings place Lebanon among countries that are highly exposed to mycotoxins through the diet and call for larger-scale studies aiming at providing a comprehensive assessment of the dietary exposure of the Lebanese population to mycotoxins as well as to other food contaminants.

Abstract. We calculate energy spectra and mass composition of cosmic rays accelerated by the galactic population of pulsars during their radio and gamma-ray phase. It is assumed that a significant part of the pulsar rotational energy is lost on acceleration of iron nuclei extracted from the surface of the neutron star. The nuclei are accelerated, at first when passing the outer gap of the inner pulsar magnetosphere and later in the pulsar wind zone, to energies corresponding to 50% of the total potential drop through the polar cap region of the neutron star. We calculate energy spectra of the nuclei injected from the pulsar wind nebulae into the Galaxy including different energy loss processes of nuclei during their propagation in the pulsar magnetosphere and the expanding nebula, their fragmentation in collisions with radiation and matter, adiabatic energy losses, and escape from the nebula. Several models proposed for the distribution of the initial parameters of the galactic pulsar population are considered. It is shown that the best description of the observed cosmic ray spectrum and the mass composition between a few 10 15 eV and a few 10 18 eV is obtained for the model B of Lorimer et al., in which the logs of initial pulsar periods and surface magnetic fields are given by the Gaussian distributions with the average values of log P[ms] = 2.6 and log B[G] = 12.3, respectively. In order to supply the cosmic rays into the Galaxy with the required rate, the product of the efficiency of cosmic ray acceleration by pulsars and their birth rate should be about 10 −2 yr −1 .

We estimate the TeV γ-ray fluxes expected from the population of young pulsars in terms of the self-consistent time dependent hadronic-leptonic model for the high energy processes inside the pulsar wind nebulae (PWNe). This radiation model bases on the hypothesis of Arons and collaborators who postulate that leptons are accelerated inside the nebulae as a result of resonant scattering on heavy nuclei, which in turn are accelerated in the pulsar wind region or the pulsar inner magnetosphere. Our aim is to find out which PWNe on the northern hemisphere are the best candidates for detection at energies above 60 GeV and 200 GeV by the next generation of low threshold Cherenkov telescopes.

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