On the nuclear symmetry energy and the neutron skin in neutron-rich nuclei

The symmetry energy for nuclear matter and its relation to the neutron skin in finite nuclei is discussed. The symmetry energy as a function of density obtained in a self-consistent Green function approach is presented and compared to the results of other recent theoretical approaches. A partial explanation of the linear relation between the symmetry energy and the neutron skin is proposed. The potential of several experimental methods to extract the neutron skin is examined.Comment: to appear in Phys. Rev.

A 10-day vacancy period after cleaning and disinfection has no effect on the bacterial load in pig nursery units

Background: Biosecurity measures such as cleaning, disinfection and a vacancy period between production cycles on pig farms are essential to prevent disease outbreaks. No studies have tested the effect of a longer vacancy period on bacterial load in nursery units. Methods: The present study evaluated the effect of a 10-day vacancy period in pig nursery units on total aerobic flora, Enterococcus spp., Escherichia coli, faecal coliforms and methicillin resistant Staphylococcus aureus (MRSA). Three vacancy periods of 10 days were monitored, each time applied in 3 units. The microbiological load was measured before disinfection and at 1, 4, 7 and 10 days after disinfection. Results: No significant decrease or increase in E. coli, faecal coliforms, MRSA and Enterococcus spp. was noticed. Total aerobic flora counts were the lowest on day 4 after disinfection (i.e. 4.07 log CFU/625 cm(2)) (P < 0.05), but the difference with other sampling moments was limited (i.e. 0.6 log CFU/625 cm(2)) and therefore negligible. Furthermore, this observation on day 4 was not confirmed for the other microbiological parameters. After disinfection, drinking nipples were still mostly contaminated with total aerobic flora (i.e. 5.32 log CFU/625 cm(2)) and Enterococcus spp. (i.e. 95 % of the samples were positive) (P < 0.01); the feeding troughs were the cleanest location (total aerobic flora: 3.53 log CFU/625 cm(2) and Enterococcus spp.: 50 % positive samples) (P < 0.01). Conclusions: This study indicates that prolonging the vacancy period in nursery units to 10 days after disinfection with no extra biosecurity measures has no impact on the environmental load of total aerobic flora, E. coli, faecal coliforms, MRSA and Enterococcus spp.

Long-range correlations in finite nuclei: comparison of two self-consistent treatments

Long-range correlations, which are partially responsible for the observed fragmentation and depletion of low-lying single-particle strength, are studied in the Green's function formalism. The self-energy is expanded up to second order in the residual interaction. We compare two methods of implementing self-consistency in the solution of the Dyson equation beyond Hartree-Fock, for the case of the 16O nucleus. It is found that the energy-bin method and the BAGEL method lead to globally equivalent results. In both methods the final single-particle strength functions are characterized by exponential tails at energies far from the Fermi level

Classification and management of allergic rhinitis patients in general practice during pollen season

Background: Allergic rhinitis (AR) represents a major challenge in primary care. The Allergic Rhinitis and its Impact on Asthma (ARIA) group proposed a new classification for AR and developed evidence-based guidelines for the management of this disease. We conducted this study to further characterize the classes of AR described by ARIA, and to evaluate whether the management of AR in general practice is in accordance with the ARIA guidelines. Methods: During the pollen season of 2003, 95 Belgian general practitioners (GPs) enrolled 804 patients who presented with symptoms of AR. For each patient, a questionnaire comprising the clinical presentation and management was completed. Results: In 64% of the patients, AR was classified as intermittent and in 36% as persistent. Persistent rhinitis caused more discomfort than intermittent rhinitis. Only 50% of the patients had ever undergone allergy testing. Among them, 51% were allergic to both seasonal and perennial allergens. Eighty-two per cent of the persistent rhinitics were allergic to at least one seasonal allergen and 72% of the intermittent rhinitics to at least one perennial allergen. When compared strictly with the ARIA recommendations, 49% of the patients with mild and/or intermittent AR were overtreated, whereas about 30% of those with moderate/severe persistent rhinitis were undertreated. Conclusion: This study confirms that the previous classification of AR into 'seasonal' and 'perennial' is not satisfactory and that intermittent and persistent AR are not equivalent to seasonal and perennial AR respectively. Furthermore, persistent rhinitis has been shown to be a distinct disease entity. Further efforts are required to disseminate and implement evidence-based diagnostic and treatment guidelines for AR in primary care practice