Abstract:
Estrogens and artificial progestins used in hormone replacement therapy increase breast cancer risk. This seems to bedue to a promoting and not initiating effect. A synergic effect of estradiol and hyperinsulinism has been shown. Insulinplays a role in the increase of breast cancer risk when associated with android obesity, sedentariness, type II diabetes,and high glycemic index food, alcohol and trans fatty acids intake. Natural menopause induces insulin resistance anddoes not induce a risk decrease. The role of insulin gives a new outlook on the influence of HRT in breast cancer promotion:estradiol alone, which improves insulin-sensitivity, does not increase breast cancer risk. Artificial progestinsassociated with estrogens increase the risk, whereas estrogens associated with progesterone do not. This could be dueto the fact that artificial progestins increase insulin resistance, whereas natural progesterone does not. Adipose tissue,which is an endocrine gland, is insulin dependant. Breast cancer and its seriousness are correlated to adipocytokincirculating levels such as resistin, leptin, interleukin 1, adipocyte fatty acid-binding protein, and are inversely correlatedto the level of adiponectin. Insulin could play a synergic role with sexual steroids by a direct effect and by increasingadipose tissue secretions.

Abstract:
Hadronic tau decays offer the possibility of determining the strong coupling alpha_s at relatively low energy. Precisely for this reason, however, good control over the perturbative QCD corrections, the non-perturbative condensate contributions in the framework of the operator product expansion (OPE), as well as the corrections going beyond the OPE, the duality violations (DVs), is required. On the perturbative QCD side, the contour-improved versus fixed-order resummation of the series is still an issue, and will be discussed. Regarding the analysis, self-consistent fits to the data including all theory parameters have to be performed, and this is also explained in some detail. The fit quantities are moment integrals of the tau spectral function data in a certain energy window and care should be taken to have acceptable perturbative behaviour of those moments as well as control over higher-dimensional operator corrections in the OPE.

Abstract:
Problem solving theory and practice suggest that thinking is more important to solving problems than knowledge and that it is possible to teach thinking in situations where little or no knowledge of the problem is needed. Such an assumption has led problem solving advocates to champion content-less heuristics as the primary element of problem solving while relegating the knowledge base and the application of concepts or transfer to secondary status. In the following theoretical analysis, it will be argued that the knowledge base and transfer of knowledge—not the content-less heuristic—are the most essential elements of problem solving.

Abstract:
The talk discusses preliminary results of an updated analysis of the strange quark mass from the scalar current QCD sum rules [1]. In particular the role of the scalar form factor which is a main ingredient in the analysis is especially emphasised. The sources of the uncertainties in the sum rule determination are briefly reviewed.

Abstract:
The talk summarises a calculation of the two-point functions for $\Delta S=1$ current-current and QCD-penguin operators, as well as for the $\Delta S=2$ operator, at the next-to-leading order. The size of the gluonic corrections to current-current operators is large, providing a qualitative understanding of the observed enhancement in $\Delta I=1/2$ transitions. In the $\Delta S=2$ sector the QCD corrections are quite moderate ($\approx -20\%$). This work has been done in collaboration with Antonio Pich.

Abstract:
Results of a recent calculation of the effective $\dS$ Hamiltonian at the next-to-leading order will be presented\footnote{Work done in collaboration with A. J. Buras and M. E. Lautenbacher.}. These, together with an improved treatment of hadronic matrix elements, are used to evaluate the measure for direct CP-violation, $\epe$, at the next-to-leading order. Taking $\mt=130\,GeV$, $\Lms=300\,MeV$ and calculating $\langle Q_6 \rangle$ and $\langle Q_8 \rangle$ in the $1/N$ approach, we find in the NDR scheme $\epe = (6.7 \pm 2.6)\times 10^{-4}$ in agreement with the experimental findings of E731. We point out however that the increase of $\langle Q_6 \rangle$ by only a factor of two gives $\epe = (20.0 \pm 6.5)\times 10^{-4}$ in agreement with the result of NA31. The dependencies of $\epe$ on $\Lms$, $\mt$, and some $B$-parameters, parameterizing hadronic matrix elements, are briefly discussed.

Abstract:
The relation between the chiral quark condensate in QCD sum rules and chiral perturbation theory is clarified with the help of a low-energy theorem for the scalar and pseudoscalar correlation functions. It is found that the quark condensate should be identified with the non-normal-ordered vacuum expectation value of quark-antiquark fields. Utilising results on flavour SU(3) breaking of the quark condensate from QCD sum rules, the unphysical low-energy constant H_2^r in the chiral Lagrangian, as well as next-to-leading order corrections to the Gell-Mann-Oakes-Renner relation are estimated.

Abstract:
The hadronic decay rate of the tau lepton serves as one of the most precise determinations of the QCD coupling alpha_s. The dominant theoretical source of uncertainty at present resides in the seeming disparity of two approaches to improving the perturbative expansion with the help of the renormalisation group, namely fixed-order and contour-improved perturbation theory. In this work it is demonstrated that in fact both approaches yield compatible results. However, the fixed-order series is found to oscillate around the contour-improved result with an oscillation frequency of approximately six perturbative orders, approaching it until about the 30th order, after which the expansion reveals its asymptotic nature. Additionally, the renormalisation scale and scheme dependencies of the perturbative series for the tau hadronic width are investigated in detail.

Abstract:
The investigation of the scalar gluonium correlator is interesting because it carries the quantum numbers of the vacuum and the relevant hadronic current is related to the anomalous trace of the QCD energy-momentum tensor in the chiral limit. After reviewing the purely perturbative corrections known up to next-next-to-leading order, the behaviour of the correlator is studied to all orders by means of the large-beta_0 approximation. Similar to the QCD Adler function, the large-order behaviour is governed by the leading ultraviolet renormalon pole. The structure of infrared renormalon poles, being related to the operator product expansion are also discussed, as well as a low-energy theorem for the correlator that provides a relation to the renormalisation group invariant gluon condensate, and the vacuum matrix element of the trace of the QCD energy-momentum tensor.