Detection of pathological lesions in slaughtered rabbits

The slaughterhouse is considered an important control point for the monitoring of rabbit diseases. In our study, 59,440 rabbit carcasses were examined, but only 1% of pathological lesions were recorded at postmortem inspection. Mainly affected were tegumentary, digestive and urinary systems. The most consistent lesion was the subcutaneous abscess; nephritis, probably caused by Encephalitozoon cuniculi, was also frequent. Pathological alterations of the liver, classified as "necrotizing hepatitis" and localized at the caudate lobe, were observed for the first time

A noncommutative Sierpinski gasket

A quantized version of the Sierpinski gasket is proposed, on purely topological grounds, as a C*-algebra A infinity with a suitable form of self-similarity. Several properties of A infinity are studied, in particular its nuclearity, the structure of ideals as well as the description of irreducible representations and extremal traces. A harmonic structure is introduced, giving rise to a self-similar Dirichlet form E. A spectral triple is also constructed, extending the one already known for the classical gasket, from which E can be reconstructed. Moreover we show that A infinity is a compact quantum metric space

Wearable piezoelectric mass sensor based on pH sensitive hydrogels for sweat pH monitoring

Colorimetric and electrochemical (bio)sensors are commonly employed in wearable platforms for sweat monitoring; nevertheless, they suffer from low stability of the sensitive element. In contrast, mass-(bio)sensors are commonly used for analyte detection at laboratory level only, due to their rigidity. To overcome these limitations, a flexible mass-(bio)sensor for sweat pH sensing is proposed. The device exploits the flexibility of piezoelectric AlN membranes fabricated on a polyimide substrate combined to the sensitive properties of a pH responsive hydrogel based on PEG-DA/CEA molecules. A resonant frequency shift is recorded due to the hydrogel swelling/shrinking at several pH. Our device shows a responsivity of about 12 kHz/pH unit when measured in artificial sweat formulation in the pH range 3-8. To the best of our knowledge, this is the first time that hydrogel mass variations are sensed by a flexible resonator, fostering the development of a new class of compliant and wearable devices

The PVLAS experiment for measuring the magnetic birefringence of vacuum

We describe the principle and status of the PVLAS experiment being prepared at the Department of Physics and INFN section in Ferrara, Italy. The goal of the experiment is to measure the magnetic birefringence of vacuum. This effect is directly connected to the vacuum QED structure and can be detected by measuring the ellipticity acquired by a linearly polarized laser beam traversing a strong magnetic field. Vacuum magnetic birefringence is predicted by the Euler-Heisenberg effective Lagrangian. The experimental method is also sensitive to new physics and could place new laboratory limits to hypothetical particles coupling to two photons, such as axion like particles, or millicharged particles

Analogue neural networks on correlated random graphs

We consider a generalization of the Hopfield model, where the entries of patterns are Gaussian and diluted. We focus on the high-storage regime and we investigate analytically the topological properties of the emergent network, as well as the thermodynamic properties of the model. We find that, by properly tuning the dilution in the pattern entries, the network can recover different topological regimes characterized by peculiar scalings of the average coordination number with respect to the system size. The structure is also shown to exhibit a large degree of cliquishness, even when very sparse. Moreover, we obtain explicitly the replica symmetric free energy and the self-consistency equations for the overlaps (order parameters of the theory), which turn out to be classical weighted sums of 'sub-overlaps' defined on all possible sub-graphs. Finally, a study of criticality is performed through a small-overlap expansion of the self-consistencies and through a whole fluctuation theory developed for their rescaled correlations: Both approaches show that the net effect of dilution in pattern entries is to rescale the critical noise level at which ergodicity breaks down.Comment: 34 pages, 3 figure

Idee e proposte per un Laboratorio Didattico di Collegamento

ItL'insegnamento della Fisica nell'Università richiede l'uso di una didattica innovativa sia negli strumenti che nelle metodologie adottate. Viene proposta l'idea di un "Laboratorio di Attività" in cui vengono realizzati percorsi didattici con una forte integrazione tra teoria ed esperimento realizzata attraverso un uso adeguato delle tecnologie informatiche

Synchronization Gauges and the Principles of Special Relativity

The axiomatic bases of Special Relativity Theory (SRT) are thoroughly re-examined from an operational point of view, with particular emphasis on the status of Einstein synchronization in the light of the possibility of arbitrary synchronization procedures in inertial reference frames. Once correctly and explicitly phrased, the principles of SRT allow for a wide range of `theories' that differ from the standard SRT only for the difference in the chosen synchronization procedures, but are wholly equivalent to SRT in predicting empirical facts. This results in the introduction, in the full background of SRT, of a suitable synchronization gauge. A complete hierarchy of synchronization gauges is introduced and elucidated, ranging from the useful Selleri synchronization gauge (which should lead, according to Selleri, to a multiplicity of theories alternative to SRT) to the more general Mansouri-Sexl synchronization gauge and, finally, to the even more general Anderson-Vetharaniam-Stedman's synchronization gauge. It is showed that all these gauges do not challenge the SRT, as claimed by Selleri, but simply lead to a number of formalisms which leave the geometrical structure of Minkowski spacetime unchanged. Several aspects of fundamental and applied interest related to the conventional aspect of the synchronization choice are discussed, encompassing the issue of the one-way velocity of light on inertial and rotating reference frames, the GPS's working, and the recasting of Maxwell equations in generic synchronizations. Finally, it is showed how the gauge freedom introduced in SRT can be exploited in order to give a clear explanation of the Sagnac effect for counter-propagating matter beams.Comment: 56 pages, 3 eps figures, invited paper; to appear in Foundations of Physics (Special Issue to honor Prof. Franco Selleri on his 70th birthday

Shape-independent scaling of excitonic confinement in realistic quantum wires

The scaling of exciton binding energy in semiconductor quantum wires is investigated theoretically through a non-variational, fully three-dimensional approach for a wide set of realistic state-of-the-art structures. We find that in the strong confinement limit the same potential-to-kinetic energy ratio holds for quite different wire cross-sections and compositions. As a consequence, a universal (shape- and composition-independent) parameter can be identified that governs the scaling of the binding energy with size. Previous indications that the shape of the wire cross-section may have important effects on exciton binding are discussed in the light of the present results.Comment: To appear in Phys. Rev. Lett. (12 pages + 2 figures in postscript

Warming and elevated CO2 promote rapid incorporation and degradation of plant-derived organic matter in an ombrotrophic peatland

Rising temperatures have the potential to directly affect carbon cycling in peatlands by enhancing organic matter (OM) decomposition, contributing to the release of CO2 and CH4 to the atmosphere. In turn, increasing atmospheric CO2 concentration may stimulate photosynthesis, potentially increasing plant litter inputs belowground and transferring carbon from the atmosphere into terrestrial ecosystems. Key questions remain about the magnitude and rate of these interacting and opposing environmental change drivers. Here, we assess the incorporation and degradation of plant- and microbe-derived OM in an ombrotrophic peatland after 4 years of whole-ecosystem warming (+0, +2.25, +4.5, +6.75 and +9°C) and two years of elevated CO2 manipulation (500 ppm above ambient). We show that OM molecular composition was substantially altered in the aerobic acrotelm, highlighting the sensitivity of acrotelm carbon to rising temperatures and atmospheric CO2 concentration. While warming accelerated OM decomposition under ambient CO2, new carbon incorporation into peat increased in warming × elevated CO2 treatments for both plant- and microbe-derived OM. Using the isotopic signature of the applied CO2 enrichment as a label for recently photosynthesized OM, our data demonstrate that new plant inputs have been rapidly incorporated into peat carbon. Our results suggest that under current hydrological conditions, rising temperatures and atmospheric CO2 levels will likely offset each other in boreal peatlands