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Since the 1960s, Egypt has sought to increase equality in access to higher education. Data show that completion of pre-tertiary education has become more equal. However, this trend toward equality did not extend to higher education. Rather, entry to higher education has become more unequal during this period, principally due to tracking at the secondary level. Secondary track is highly correlated with wealth: students from the poorest families overwhelming attend technical education; most children from wealthy families attend general (academic) secondary. Lucas (2001) has called this relationship between wealth and tracking “Effectively Maintained Inequality.”

How much work is “too much” for children aged 10–14 in Egypt? Our narrow focus here is on “work that does not interfere with school attendance.” For girls, work includes time spent in household chores and subsistence activities. We estimate simultaneous hours of work and school attendance equations as a joint Tobit and Probit model, then conduct simulations. Substantial negative effects on attendance are observed above about 10 hours per week (girls) and 14 hours (boys). For girls, heavy household work appears causal, but for boys, it seems that poor schooling leads to boys' dropout, then subsequent work.

The purpose of this paper is to perform experimental investigation and constitutive modeling of the viscoelastic and viscoplastic behavior of metallocene catalyzed polypropylene (mPP) with application to lifetime assessment under conditions of creep rupture.

Three series of experiments are conducted where the mechanical response of mPP is analyzed in tensile tests with various strain rates, relaxation tests with various strains, and creep tests with various stresses at room temperature. A constitutive model is derived for semicrystalline polymers under an arbitrary three‐dimensional deformation with small strains, and its parameters are found fitting the observations.

Crystalline structure and molecular architecture of polypropylene strongly affect its time‐ and rate‐dependent behavior. In particular, time‐to‐failure of metallocene catalyzed polypropylene under tensile creep noticeably exceeds that of isotactic polypropylene produced by the conventional Ziegler‐Natta catalysis.

Novel stress‐strain relations are developed in viscoelastoplasticity of semi‐crystalline polymers and applied to predict their mechanical behavior in long‐term creep tests.