In Egypt, pneumococcal vaccines have not yet been introduced as being compulsory. Identification of the circulating serotypes in Egypt is mandatory to determine whether or not the pneumococcal vaccines will be beneficial. The current study aims to identify the serotypes, vaccine coverage, and antimicrobial resistance of Streptococcus pneumoniae colonizing the nasopharynx of Egyptian children younger than 5 years old. The study was conducted in two successive winter seasons (December 2012-February 2013 and December 2013-February 2014). Two hundred children were enrolled, aged from 6 months to 5 years, excluding those with fever, signs of infection, history of antibiotic intake, and hospitalization in the preceding month. Nasopharyngeal (NP) secretions were collected, subjected to culture, and underwent antibiotic susceptibility testing if positive for pneumococci. Real-time polymerase chain reaction (PCR) and serotyping by sequential multiplex PCR for positive cases were included as well. Streptococcus pneumoniae was isolated from 62 subjects. All isolates were sensitive to vancomycin and levofloxacin, but the majority showed resistance to multiple antibiotics. PCR was positive for pneumococci in 113 subjects (56.5%). The most commonly detected serotypes (st) were 6A6B6C (n = 21, 20.8%), 19F (n = 19, 18.8%), 1 (n = 11, 10.9%), 34 (n = 8, 7.9%), and 19A (n = 6, 5.9%). The theoretical coverage of the PCV13 vaccine for the detected serotypes was 72.4%, while that of PCV10 was 65.5%. Based on these percentages, we recommend including pneumococcal conjugate vaccines in the Egyptian national vaccination program.

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Relativistic calculations of the induced proton polarization in quasifree electron scattering on 12 C are presented. Good agreement with the experimental data of Woo et al. is obtained. The relativistic calculations yield a somewhat better description of the data than the nonrelativistic ones. Differences between the two approaches are more pronounced at larger missing momenta suggesting further experimental work in this region.

The relativistic amplitude for the direct knock-out contribution to (γ, p) reactions on nuclei is reduced to a nonrelativistic form using an effective Pauli reduction scheme. The reduction is carried out to second order in the inverse nucleon mass. It is found that the interaction Hamiltonian appearing in the nonrelativistic amplitude has significant dependence, starting at second order, on the vector and scalar mean nuclear potentials. These strong medium modifications are absent in traditional nonrelativistic calculations. Detailed comparisons show that these modifications are crucial to understanding the differences between relativistic and nonrelativistic models. These differences are also examined through reduction of the relativistic amplitude via the Foldy-Wouthuysen transformation. Similar medium modifications are obtained in this case as well. We discuss the implications of these medium modifications for the consistency of existing nonrelativistic calculations.

Spectroscopic amplitudes play an important role in nuclear capture reactions. These amplitudes are shown to include both single-particle and polarization effects: the former through their spatial dependence and the latter through their normalization (the spectroscopic factors). Coupled-channels equations are developed for the spectroscopic amplitudes. These equations serve as a convenient starting point for the derivation of several approximations: Hartree, Hartree-Fock and two different single-particle models. The single-particle models include antisymmetry in different ways, but both miss many-body effects. Therefore, cross sections calculated with either of these models need to be multiplied by the spectroscopic factor.

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A relativistic model for the quasifree photoproduction of η meson from complex nuclei is developed. The interactions between fields are introduced through effective Lagrangians. Contributions from several nucleon resonances as well as nucleon Born terms and vector meson exchange diagrams are included. Nucleon and η wave functions are solutions of Dirac and Klein-Gordon equations, respectively. Final state interactions of the outgoing particles are included via optical potentials. The effects of these interactions on the cross sections and photon asymmetries are studied and are found to be large. Calculations indicate that at energies near threshold the exclusive reaction takes place mainly through formation of the S 11 ( 1535 ) resonance. Comparisons with the non-relativistic calculations show differences between the two approaches both for the cross sections and photon asymmetries. We give some detailed predictions for the reaction observables for exclusive photoproduction on 12 C, 16 O and 40 Ca. PACS number(s) 25.20.Lj, 24.10.Jv, 24.70+s, 13.60.Le

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