Coralline algae in a naturally acidified ecosystem persist by maintaining control of skeletal mineralogy and size

To understand the effects of ocean acidification (OA) on marine calcifiers, the trade-offs among different sublethal responses within individual species and the emergent effects of these trade-offs must be determined in an ecosystem setting. Crustose coralline algae (CCA) provide a model to test the ecological consequences of such sublethal effects as they are important in ecosystem functioning, service provision, carbon cycling and use dissolved inorganic carbon to calcify and photosynthesize. Settlement tiles were placed in ambient pH, low pH and extremely low pH conditions for 14 months at a natural CO2 vent. The size, magnesium (Mg) content and molecular-scale skeletal disorder of CCA patches were assessed at 3.5, 6.5 and 14 months from tile deployment. Despite reductions in their abundance in low pH, the largest CCA from ambient and low pH zones were of similar sizes and had similar Mg content and skeletal disorder. This suggests that the most resilient CCA in low pH did not trade-off skeletal structure to maintain growth. CCA that settled in the extremely low pH, however, were significantly smaller and exhibited altered skeletal mineralogy (high Mg calcite to gypsum (hydrated calcium sulfate)), although at present it is unclear if these mineralogical changes offered any fitness benefits in extreme low pH. This field assessment of biological effects of OA provides endpoint information needed to generate an ecosystem relevant understanding of calcifying system persistence

A superfluid-droplet crystal and a free-space supersolid in a dipole-blockaded gas

A novel supersolid phase is predicted for an ensemble of Rydberg atoms in the dipole-blockade regime, interacting via a repulsive dipolar potential "softened" at short distances. Using exact numerical techniques, we study the low temperature phase diagram of this system, and observe an intriguing phase consisting of a crystal of mesoscopic superfluid droplets. At low temperature, phase coherence throughout the whole system, and the ensuing bulk superfluidity, are established through tunnelling of identical particles between neighbouring droplets.Comment: 4 pages, 4 figure

Strongly correlated gases of Rydberg-dressed atoms: quantum and classical dynamics

We discuss techniques to generate long-range interactions in a gas of groundstate alkali atoms, by weakly admixing excited Rydberg states with laser light. This provides a tool to engineer strongly correlated phases with reduced decoherence from inelastic collisions and spontaneous emission. As an illustration, we discuss the quantum phases of dressed atoms with dipole-dipole interactions confined in a harmonic potential, as relevant to experiments. We show that residual spontaneous emission from the Rydberg state acts as a heating mechanism, leading to a quantum-classical crossover.Comment: 4 pages, 4 figure

Analysis of flow cytometric aneuploid DNA histograms: validation of an automatic procedure against ad hoc experimental data

In this paper we present an improved version of a method for the automatic analysis of flow cytometric DNA histograms from samples containing a mixture of two cell populations. The procedure is tested against two sets of ad hoc experimental data, obtained by mixing cultures of cell lines in different known proportions. The potentialities of the method are enlightened and discussed with regard to its capability of recovering the population percentages, the DNA index and the G0/G1, S, G2+M phase fractions of each population. On the basis of the obtained results, the procedure appears to be a promising tool in the flow cytometric data analysis and, in particular, in problems of diagnosis and prognosis of tumor diseases

Instanton traces in lattice gluon correlation functions

Strong coupling constant computed in Landau gauge and MOM renormalization scheme from lattice two and three gluon Green Functions exhibits an unexpected behavior in the deep IR, showing a maximum value around $1 {\rm GeV}$. We analise this coupling below this maximum within a semiclassical approach, were gluon degrees of freedom at very low energies are described in terms of the classical solutions of the lagrangian, namely instantons. We provide some new results concerning the relationship between instantons and the low energy dynamics of QCD, by analising gluon two- and three-point Green functions separately and with the help of a cooling procedure to eliminate short range correlations.Comment: 4 pages, talk given at XXXX Rencontres de Moriond on QCD and Hadronic Interactions, La Thuile (Italy

What is a Gene? A Two Sided View

The need to account for all currently available experimental observations concerning the gene nature, has reshaped the concept of gene turning it from the essentially mechanistic unit, predominant during the '70s, into a quite abstract open and generalized entity, whose contour appears less defined as compared to the past. Here we propose the essence of the gene to be considered double faced. In this respect genotypic and phenotypic entities of a gene would coexist and mix reciprocally. This harmonizes present knowledge with current definitions and predisposes for remodelling of our thinking as a consequence of future discoveries. A two sided view of the gene also allows to combine the genetic and epigenetic aspects in a unique solution, being structural and functional at the same time and simultaneously able to include the different levels in an overlapping unicum

Influence of Polymer Solution on Pump Performances

5In professional warewashing machines, as for example the model of Electrolux Rack Type, the working conditions of the pump are affected by the operating fluid properties, which are different from those of pure water. In fact, the actual trend in this kind of professional appliances is to reduce both energy consumption and time needed for cleaning process: this involves short washing cycles conducted at low temperatures with a solution of water and highly concentrated chemistry. Detergents contain different components and additives, as polymers and surfactants, which can affect the performance of the pump, including cavitation inception conditions. Cavitation leads to flow instabilities, affecting pump performances and inducing an increment in the level of vibrations and noise. While cavitation phenomena in Newtonian fluids is well known, particularly as far as pure water is concerned, in literature there are also various studies on cavitating flows in presence of diluted solutions of polymers additives in water, but only few studies are available regarding the effect of detergent components on pumps cavitation and, in general, on pumps performances. The wide range of variables affecting the phenomenon has led to the development of a laboratory rig for testing centrifugal pumps with aqueous solutions representative of those used in the warewashing sector [1]. This paper presents the results of tests performed with various solutions of a polymer (Polyox WSR301) in water. A rheometric analysis has been previously performed on samples of some of the tested solutions, for characterizing their behavior in terms of both viscosity in laminar conditions and their classification as “diluted” or “concentrated”. For each solution, the resulting performance curves of the pump are then compared with those obtained with pure water.openopenBurlon, F.; Micheli, D.; Furlanetto, R.; Simonato, M.; Cucit, V.Burlon, Fabio; Micheli, Diego; Furlanetto, R.; Simonato, M.; Cucit, Valentin

Designing spin-1 lattice models using polar molecules

We describe how to design a large class of always on spin-1 interactions between polar molecules trapped in an optical lattice. The spin degrees of freedom correspond to the hyperfine levels of a ro-vibrational ground state molecule. Interactions are induced using a microwave field to mix ground states in one hyperfine manifold with the spin entangled dipole-dipole coupled excited states. Using multiple fields anistropic models in one, two, or three dimensions, can be built with tunable spatial range. An illustrative example in one dimension is the generalized Haldane model, which at a specific parameter has a gapped valence bond solid ground state. The interaction strengths are large compared to decoherence rates and should allow for probing the rich phase structure of strongly correlated systems, including dimerized and gapped phases.Comment: 24 pages, 5 figure

Quantum Degenerate Systems

Degenerate dynamical systems are characterized by symplectic structures whose rank is not constant throughout phase space. Their phase spaces are divided into causally disconnected, nonoverlapping regions such that there are no classical orbits connecting two different regions. Here the question of whether this classical disconnectedness survives quantization is addressed. Our conclusion is that in irreducible degenerate systems --in which the degeneracy cannot be eliminated by redefining variables in the action--, the disconnectedness is maintained in the quantum theory: there is no quantum tunnelling across degeneracy surfaces. This shows that the degeneracy surfaces are boundaries separating distinct physical systems, not only classically, but in the quantum realm as well. The relevance of this feature for gravitation and Chern-Simons theories in higher dimensions cannot be overstated.Comment: 18 pages, no figure