Finite Volume Scaling of Pseudo Nambu-Goldstone Bosons in QCD

We consider chiral perturbation theory in a finite volume and in a mixed regime of quark masses. We take N_l light quarks near the chiral limit, in the so-called epsilon-regime, while the remaining N_h quarks are heavier and in the standard p-regime. We compute in this new mixed regime the finite-size scaling of the light meson correlators in the scalar, pseudoscalar, vector and axial vector channels.Using the replica method, we easily extend our results to the partially quenched theory. With the help of our results, lattice QCD simulations with 2+1 flavors can safely investigate pion physics with very light up and down quark masses even in the region where the pion's correlation length overcomes the size of the space-time lattice.Comment: 32 pages, 6 figures, published versio

Mixed action computations on fine dynamical lattices

We report on our first experiences in simulating Neuberger valence fermions on CLS $N_f=2$ configurations with light sea quark masses and small lattice spacings. Valence quark masses are considered that allow to explore the matching to (partially quenched) chiral perturbation theory both in the $\epsilon$- and $p$-regimes. The setup is discussed, and first results are presented for spectral observables.Comment: 7 pages. Presented at the XXVII International Symposium on Lattice Field Theory, July 26-31, 2009, Peking University, Beijing, Chin

Finite-size scaling for the left-current correlator with non-degenerate quark masses

We study the volume dependence of the left-current correlator with non-degenerate quark masses to next-to-leading order in the chiral expansion. We consider three possible regimes: all quark masses are in the $\epsilon$-regime, all are in the $p$-regime and a mixed-regime where the lighest quark masses satisfy $m_v \Sigma V \leq 1$ while the heavier $m_s \Sigma V \gg 1$. These results can be used to match lattice QCD and the Chiral Effective Theory in a large but finite box in which the Compton wavelength of the lightest pions is of the order of the box size. We consider both the full and partially-quenched results.Comment: 27 pages, 4 figure

The reticulons: guardians of the structure and function of the endoplasmic reticulum

The endoplasmic reticulum (ER) consists of the nuclear envelope and a peripheral network of tubules and membrane sheets. The tubules are shaped by a specific class of curvature stabilizing proteins, the reticulons and DP1; however it is still unclear how the sheets are assembled. The ER is the cellular compartment responsible for secretory and membrane protein synthesis. The reducing conditions of ER lead to the intra/inter-chain formation of new disulphide bonds into polypeptides during protein folding assessed by enzymatic or spontaneous reactions. Moreover, ER represents the main intracellular calcium storage site and it plays an important role in calcium signaling that impacts many cellular processes. Accordingly, the maintenance of ER function represents an essential condition for the cell, and ER morphology constitutes an important prerogative of it. Furthermore, it is well known that ER undergoes prominent shape transitions during events such as cell division and differentiation. Thus, maintaining the correct ER structure is an essential feature for cellular physiology. Now, it is known that proper ER-associated proteins play a fundamental role in ER tubules formation. Among these ER-shaping proteins are the reticulons (RTN), which are acquiring a relevant position. In fact, beyond the structural role of reticulons, in very recent years new and deeper functional implications of these proteins are emerging in relation to their involvement in several cellular processes

Il concorso tra reato e illecito amministrativo di fonte regionale alla prova del ne bis in idem convenzionale

La sentenza che si annota si muove in un terreno gi\ue0 ampiamente battuto dalla dottrina e dalla giurisprudenza interna, sia di merito che di legittimit\ue0. Tratta, infatti, la vexata quaestio della compatibilit\ue0 di sistemi a \u201cdoppio binario\u201d con il principio del ne bis in idem convenzionale. La specificit\ue0 di questa pronuncia, per\uf2, sta nel fatto che per la prima volta il problema si pone in relazione ad un illecito amministrativo di fonte regionale applicato in concorso con un reato, in esito a due distinti procedimenti. La pronuncia risolve il problema ricorrendo alla \u201cvalvola di sfogo\u201d offerta dalla Grande Camera di Strasburgo nel noto caso A e B c. Norvegia; tuttavia essa spinge l\u2019interprete a confrontarsi, ancora una volta, con un tema sempre vivo, nonostante il revirement operato dalla Grande Camera, e a ricercare gli strumenti idonei a garantire il rispetto del diritto convenzionale innanzitutto tra gli istituti che il diritto interno mette a disposizione. L\u2019articolo si propone di dimostrare come i meccanismi di raccordo tra illecito amministrativo e reato, predisposti dal legislatore del 1981 con la l. n. 689, possano oggi essere valorizzati \u2013 almeno in relazione a questo specifico caso, ma con possibilit\ue0 di estendere l\u2019operazione ad altre situazioni analoghe \u2013 per garantire l\u2019unicit\ue0 dell\u2019accertamento richiesta dalla Corte europea dei diritti dell\u2019uomo sulla base dell\u2019art. 4 Prot. 7 CEDU