Phase transition from nuclear matter to color superconducting quark matter: the effect of the isospin

We compute the mixed phase of nuclear matter and 2SC matter for different temperatures and proton fractions. After showing that the symmetry energy of the 2SC phase is, to a good approximation, three times larger than the one of the normal quark phase, we discuss and compare all the properties of the mixed phase with a 2SC component or a normal quark matter component. In particular, the local isospin densities of the nuclear and the quark component and the stiffness of the mixed phase are significantly different whether the 2SC phase or the normal quark phase are considered. If a strong diquark pairing is adopted for the 2SC phase, there is a possibility to eventually enter in the nuclear matter 2SC matter mixed phase in low energy heavy ions collisions experiments. Possible observables able to discern between the formation of the 2SC phase or the normal quark phase are finally discussed.Comment: 9 pages, 8 figure

Stability of CFL cores in Hybrid Stars

We study the equation state of strongly interacting quark matter within a NJL-like model in which the chiral condensates and the color superconducting gaps are computed self-consistently as a function of the baryon density. A vector interaction term is added to the Lagrangian in order to render the quark matter equation of state stiffer. For the low density hadronic phase we use a relativistic mean field model. The phase transition to quark matter is computed by a Maxwell construction. We show that stable CFL cores in hybrid stars are possible if the superconducting gap is sufficiently large. Moreover we find stable stellar configurations in which two phase transitions occur, a first transition from hadronic matter to 2SC quark matter and a second transition from 2SC quark matter to CFL quark matter.Comment: 10 pages, 6 figure

Formation of quark phases in compact stars and SN explosion

We describe possible scenarios of quark deconfinement in compact stars and we analyze their astrophysical implications. The quark deconfinement process can proceed rapidly, as a strong deflagration, releasing a huge amount of energy in a short time and generating an extra neutrino burst. If energy is transferred efficiently to the surface, like e.g. in the presence of convective instabilities, this burst could contribute to revitalize a partially failed SN explosion. We discuss how the neutrino observations from SN1987A would fit in this scenario. Finally, we focus on the fate of massive and rapidly rotating progenitors, discussing possible time separations between the moment of the core collapse and the moment of quark deconfinement. This mechanism can be at the basis of the interpretation of gamma ray bursts in which lines associated with heavy elements are present in the spectrum.Comment: 9 pages, 3 figures, Proceedings "6th International Conference on Perspectives in Hadronic Physics", May 2008, Triest

Neutron stars within the SU(2) parity doublet model

The equation of state of beta-stable and charge neutral nucleonic matter is computed within the SU(2) parity doublet model in mean field and in the relativistic Hartree approximation. The mass of the chiral partner of the nucleon is assumed to be 1200 MeV. The transition to the chiral restored phase turns out to be a smooth crossover in all the cases considered, taking place at a baryon density of just $2\rho_0$. The mass-radius relations of compact stars are calculated to constrain the model parameters from the maximum mass limit of neutron stars. It is demonstrated that chiral symmetry starts to be restored, which in this model implies the appearance of the chiral partners of the nucleons, in the center of neutron stars. However, the analysis of the decay width of the assumed chiral partner of the nucleon poses limits on the validity of the present version of the model to describe vacuum properties.Comment: 14 pages, 9 figures, 2 tables, version accepted for publication in EJP

Advanced Processing of Micropatterned Elasto-Magnetic Membranes

This is the author accepted manuscript. The final version is available from IEEE via the DOI in this record The dataset associated with this article is located in ORE at: https://doi.org/10.24378/exe.1263We report on a fabrication of a highly structured elasto-magnetic membrane with microscopic unit cells using lithographic techniques and electrodeposition. The membrane comprises micromagnets of CoNiP and Co connected via an elastic PDMS network with an area spanning 12 mm². Ellipsoidal CoNiP and circular Co particles were produced by electrodeposition to achieve diameters of 30 (major) and 10 μ m (minor) and 10 μm, respectively, with a thickness in the range of 6-10 μm. The electrodeposition parameters have been optimized on deposition of CoNiP films to produce an in-plane coercivity for CoNiP elements of 435 Oe. The mechanical properties of the elasto-magnetic membrane were confirmed on application of an alternating magnetic field. The proposed methodology offers a new way for fabrication of novel microfluidic and microelectro-mechanical-systems devices.Engineering and Physical Sciences Research Council (EPSRC)European Union Horizon 202

Magnetic field generated by r-modes in accreting quark stars

We show that the r-mode instability can generate strong toroidal fields in the core of accreting millisecond quark stars by inducing differential rotation. We follow the spin frequency evolution on a long time scale taking into account the magnetic damping rate in the evolution equations of r-modes. The maximum spin frequency of the star is only marginally smaller than in the absence of the magnetic field. The late-time evolution of the stars which enter the r-mode instability region is instead rather different if the generated magnetic fields are taken into account: they leave the millisecond pulsar region and they become radio pulsars.Comment: 8 pages, 8 figure

Production of benzaldehyde, benzyl alcohol and benzoic acid by yeasts and Botrytis cinerea isolated from grape musts and wines

The capacity of 100 yeast strains - isolated from grape musts and wines from the Istituto Sperimentale per l'Enologia collection - to produce benzaldehyde, benzyl alcohol and benzoic acid was verified by inoculation into a synthetic nutrient medium (MNS). Schizosaccharomyces and Zygosaccharomyces were strongest in producing benzaldehyde (maximal amount found 1200 µg/l) and benzyl alcohol (maximally 523 µg/l). Zygosaccharomyces was also most effective in the production of benzoic acid (maximally 536 µg/l), followed by Saccharomyces, Cryptococcus, Kloeckera and Torulaspora. The hypothesis was verified that yeasts can be an exogenous source of the benzyl alcohol oxidizing enzyme in grape musts and wines. Wine yeast strains of Saccharomyces spp., Zygosaccharomyces spp. and Schizosaccharomyces spp. fermenting MNS containing 150 g/l glucose, with benzyl alcohol added, transformed this into benzoic acid only when glucose was disappearing, but not into benzaldehyde. No difference was observed between aerobic and anaerobic fermentation conditions. The uptake of benzyl alcohol was rapid in fermentation essays in presence of only 10 g/l glucose and in assimilation essais performed in yeast nitrogen base broth with assimilable carbon compounds added. A catabolic repression by glucose appears likely. Botrytis cinerea was able to transform benzyl alcohol into benzaldehyde and benzoic acid on Czapek-Dox broth with 30 g/l sucrose added. Benzyl alcohol was transformed by wine yeasts into benzoic acid when the concentration of glucose in the mineral medium was less than 10 g/l, but no production of benzaldehyde was observed. A catabolic repression of this transformation by glucose is likely. Botrytis cinerea was able to produce benzaldehyde in a mineral medium with benzyl alcohol and sucrose added

Versatile multiplexed super-resolution imaging of nanostructures by Quencher-Exchange-PAINT

This is the final version of the article. Available from Springer Verlag via the DOI in this record.The optical super-resolution technique DNA-PAINT (Point Accumulation Imaging in Nanoscale Topography) provides a flexible way to achieve imaging of nanoscale structures at ∼10-nanometer resolution. In DNA-PAINT, fluorescently labeled DNA “imager” strands bind transiently and with high specificity to complementary target “docking” strands anchored to the structure of interest. The localization of single binding events enables the assembly of a super-resolution image, and this approach effectively circumvents photobleaching. The solution exchange of imager strands is the basis of Exchange-PAINT, which enables multiplexed imaging that avoids chromatic aberrations. Fluid exchange during imaging typically requires specialized chambers or washes, which can disturb the sample. Additionally, diffusional washout of imager strands is slow in thick samples such as biological tissue slices. Here, we introduce Quencher-Exchange-PAINT—a new approach to Exchange-PAINT in regular open-top imaging chambers—which overcomes the comparatively slow imager strand switching via diffusional imager washout. Quencher-Exchange-PAINT uses “quencher” strands, i.e., oligonucleotides that prevent the imager from binding to the targets, to rapidly reduce unwanted single-stranded imager concentrations to negligible levels, decoupled from the absolute imager concentration. The quencher strands contain an effective dye quencher that reduces the fluorescence of quenched imager strands to negligible levels. We characterized Quencher-Exchange-PAINT when applied to synthetic, cellular, and thick tissue samples. Quencher-Exchange-PAINT opens the way for efficient multiplexed imaging of complex nanostructures, e.g., in thick tissues, without the need for washing steps. [Figure not available: see fulltext.]The work was supported by funding from the Human Frontier Science Program (No. 0027/2013) and the Engineering and Physical Sciences Research Council of the UK (No. EP/N008235/1)