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E the !& decade jet physics h s bee. i&~sive!y .?-.died zt ete-afid hadro~ic colliders. With the start of LEP activity a wealth of new data has become available (see, for example, [l]). They show that the global features of hadronic jets systems (multiplicities, angular patterns of particle flows, inclusive energy spectra etc), calcnlated at the parton level, agree very well with the measured ones. This convincingly demonstrates the dominant role of the perturbative (PT) phase of jet evolution and strongly supports the hypothesis of local parton-hadron duality (LPHD) [Zj 31; Such a local duality is naturally connected with the 'preconfinement' properties [4] of the QCD cascades. Together with the modified leading logarithmic approximation (MLLA)

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The authors review the ideas and manifestations of QCD coherence in high-energy reactions producing jets. They suggest experiments involving two-jet production, high-p^ production and high-/^ ^production at hadronic colliders as ways to see QCD coherence in stringlike effects. They also suggest a procedure for finding the dip in the inclusive hadron spectrum of jets for those jets produced at hadron colliders. Simple explanations of the various coherence effects in QCD are discussed, as is the idea of local parton-hadron duality.

A perturbative QCD formula ~for inclusive energy spectra of heavy quarks from heavy quark initiated jets, which takes into account collinear and/or soft logarithms in all orders, the exact first order result, and two-loop effects is applied to distributions of heavy flavored hadrons in the framework of the local parton-hadron duality concept. PACS number(s): 13.65.+i, 12.38.Bx, 13.87.-a SPECIFIC FEATURES OF HEAVY QUARK PRODUCTION: . . .

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New results in applications of the analytical perturbative approach to the description of particle distributions in QCD jets are presented. We study inclusive energy spectra of partons from QCD cascades truncated at different values of the cutoff parameter Q0, which can be used to model the energy distributions of massive hadrons in the framework of the local parton-hadron duality hypothesis. Results of straightforward numerical calculations of parton distributions which solve the MLLA evolution equations are compared to approximate formulas representing the spectra in terms of a few analytically calculated shape parameters.