The Interplay Between GUT and Flavour Symmetries in a Pati-Salam x S4 Model

Both Grand Unified symmetries and discrete flavour symmetries are appealing ways to describe apparent structures in the gauge and flavour sectors of the Standard Model. Both symmetries put constraints on the high energy behaviour of the theory. This can give rise to unexpected interplay when building models that possess both symmetries. We investigate on the possibility to combine a Pati-Salam model with the discrete flavour symmetry $S_4$ that gives rise to quark-lepton complementarity. Under appropriate assumptions at the GUT scale, the model reproduces fermion masses and mixings both in the quark and in the lepton sectors. We show that in particular the Higgs sector and the running Yukawa couplings are strongly affected by the combined constraints of the Grand Unified and family symmetries. This in turn reduces the phenomenologically viable parameter space, with high energy mass scales confined to a small region and some parameters in the neutrino sector slightly unnatural. In the allowed regions, we can reproduce the quark masses and the CKM matrix. In the lepton sector, we reproduce the charged lepton masses, including bottom-tau unification and the Georgi-Jarlskog relation as well as the two known angles of the PMNS matrix. The neutrino mass spectrum can present a normal or an inverse hierarchy, and only allowing the neutrino parameters to spread into a range of values between $\lambda^{-2}$ and $\lambda^2$, with $\lambda\simeq0.2$. Finally, our model suggests that the reactor mixing angle is close to its current experimental bound.Comment: 62 pages, 4 figures; references added, version accepted for publication in JHE

Massive haematoma formation associated with proximal popliteal artery haemangioendothelioma in a dog

A mixed breed dog presented with diffuse unilateral hind limb swelling, which ultrasound and cytology confirmed to be caused by severe haematoma formation. Multi-detector computed tomography (MDCT) angiography allowed distinct visualisation of an anomalous segment of the proximal popliteal artery, the presumed origin of the self-sustaining haematoma. Histopathology classified the malformed vessel as a haemangioendothelioma, a neoplasia of intermediate malignancy. Considering this as differential diagnosis to a neoplastic vascular alteration of high malignancy (such as haemangiosarcoma) might alter choice of treatment in future cases with similar clinical and imaging findings

Tomography and Static-Mechanical Properties of Adherent Cells

A tomography approach is used to reconstruct 3D cell shapes and, simultaneously, the shapes/positions of the nuclei within these cells. Subjecting the cells to well-defined microconfinements of various diameters allow for relating the steady-state shapes of cells to their static-mechanical properties. The observed shapes show striking regularities between different cell types and all fit to a model that takes into account the cell membrane, cortical actin, and the nucleus