On the classification of complete area-stationary and stable surfaces in the sub-Riemannian Sol manifold

We study the classification of area-stationary and stable $C^2$ regular surfaces in the space of the rigid motions of the Minkowski plane E(1,1), equipped with its sub-Riemannian structure. We construct examples of area-stationary surfaces that are not foliated by sub-Riemannian geodesics. We also prove that there exist an infinite number of $C^2$ area-stationary surfaces with a singular curve. Finally we show the stability of $C^2$ area-stationary surfaces foliated by sub-Riemannian geodesics

Regularity of C1C^1 surfaces with prescribed mean curvature in three-dimensional contact sub-Riemannian manifolds

In this paper we consider surfaces of class $C^1$ with continuous prescribed mean curvature in a three-dimensional contact sub-Riemannian manifold and prove that their characteristic curves are of class $C^2$. This regularity result also holds for critical points of the sub-Riemannian perimeter under a volume constraint. All results are valid in the first Heisenberg group $\mathbb{H}^1$.Comment: 12 pages. Final version to appear in Calc. Var. PD

Active stabilization of a Michelson interferometer at an arbitrary phase with sub-nm resolution

We report on the active stabilization of a Michelson interferometer at an arbitrary phase angle with a precision better than one degree at $\lambda = 632.8$ nm, which corresponds to an optical path difference between the two arms of less than 1 nm. The stabilization method is ditherless and the error signal is computed from the spatial shift of the interference pattern of a reference laser, measured in real-time with a CCD array detector. We discuss the usefulness of this method for nanopositioning, optical interferometry and quantum optical experiments

Constraints on cosmological parameters from future cosmic microwave background experiments

The Planck satellite experiment will soon let cosmologists to determine most of the cosmological parameters with unprecedented accuracy. In particular a strong improvement is expected in many parameters of interest, including neutrino mass, the amount of relativistic particles at recombination, the primordial Helium abundance and the injection of extra ionizing photon by dark matter self-annihilation. Here we review the constraints achievable by future experiments and discuss the implications for fundamental physics. © 2010 IOP Publishing Ltd

Contributo per una conoscenza analitica delle Mura Bolognesi: Il rilievo critico

Per la prima volta viene affrontato in modo critico e definito il rilievo diretto delle mura e delle porte della terza cerchia di Bologna. La restituzione grafica del testo architettonico è fondamentale non solo per gli studi sui materiali e sulle tecniche che compongono i vari manufatti afferenti al sistema fortificato, ma anche per una lettura cronologica delle stratificazioni che si sono sedimentate nel corso dei secoli. In particolare vengono analizzate direttamente sul testo architettonico le fasi costruttive di Porta Mascarella e Porta San Donato e vengono comparate fra loro cartografie inedite relative alla struttura geometrica delle mura con i relativi elementi accessori, quali cancella, fossato, terrapieni, ecc.

Ecology of Italian Protura

The ecology of Protura in Italy (including Corsica) is tentatively described according to original and bibliographical data. Protura are quite common but very rarely abundant: their mean density in soil samples collected in Liguria (NW Italy) was estimated to be 372 /m\ub2 (s.d. 657 \u2013 max. 2790 /m\ub2 in a Holm oak forest). Information from the analyses of habitat and/or elevation of 3448 specimens from 269 collections and 4071 specimens from 295 collections identified to species and genus level, respectively, enabled us to outline Protura assemblages for eight different macro-habitats. The unbalanced sex ratio in favour of females observed in 12 of the dominant species of Acerentomata suggests that (based also on the sperm types known in Protura) a single male can fertilize several females through spermatophores. For one species (Proturentomon minimum) only females were collected, which may suggest the possibility of parthenogenesis in some Protura. An analysis of the phenology and population dynamics of the five dominant species, showed annual cycles with one (Acerentomon microrhinus) or more (A. gallicum, A. italicum, A. maius and Eosentomon transitorium) peaks of reproductive activity. Other ecological remarks (e.g. about the relationship between the amplitude of latitudinal/altitudinal distribution and the ecological distribution of Protura in Italy) are discussed

Pharmacological thromboprophylaxis in acutely ill medical patients: some work remains to be done

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Constraining Fundamental Physics with Future CMB Experiments

The Planck experiment will soon provide a very accurate measurement of Cosmic Microwave Background anisotropies. This will let cosmologists determine most of the cosmological parameters with unprecedented accuracy. Future experiments will improve and complement the Planck data with better angular resolution and better polarization sensitivity. This unexplored region of the CMB power spectrum contains information on many parameters of interest, including neutrino mass, the number of relativistic particles at recombination, the primordial Helium abundance and the injection of additional ionizing photons by dark matter self-annihilation. We review the imprint of each parameter on the CMB and forecast the constraints achievable by future experiments by performing a Monte Carlo analysis on synthetic realizations of simulated data. We find that next generation satellite missions such as CMBPol could provide valuable constraints with a precision close to that expected in current and near future laboratory experiments. Finally, we discuss the implications of this intersection between cosmology and fundamental physics.Comment: 11 pages, 14 figure