abstract

We treat the galactic fluid, in the early epochs of the Universe, as a nonlinear Stokesiati fluid. Some general comments on fluids with viscosity are made. Then we examine an exact solution and give a qualitative analysis for a Bianchi type-I cosmological model generated by a fluid whose viscosity depends quadratically on the deformation tensor.

abstract

The evolution of Friedman models with arbitrary pressure \(p = p(\varepsilon , H)\) in the phase plane: Hubble function-energy density a is presented. The conclusions are: critical points of the phase plane and their stability depend on energy conditions but not on the actual form of pressure; models with constant viscosity violate the condition \(e+p \geq 0\); the weak and the strong energy conditions are preserved if the viscosity coefficient is proportional to \(\varepsilon ^{1/2}\).

abstract

The \(\tau \to \nu \rho \pi \) decay parameters are evaluated using the PCAC hypothesis and current algebraic methods. The angular and energy distributions are obtained. The polarization effects are discussed in detail. We showed that the \(D\)-wave contribution (in A\(_1 \to \rho \pi \) decay) is suppressed.

abstract

A comparison is made between QCD predictions and the moments of the structure and fragmentation functions measured in lepton-nucleon scattering. The data are quantitatively consistent with the leading order theory, for \(q^2 \gt 1\) GeV\(^2\). The fits are not so good when present calculations of next to leading order corrections are taken into account. Moments of the structure and fragmentation functions of the gluons are in rough accord with expectations.

abstract

These lectures are an introduction to the standard weak-electromagnetic gauge model and its experimental tests, followed by six-quark phenomenology and some Grand Unification schemes.