Evidence for a spin-aligned neutron-proton paired phase from the level structure of (92)Pd.

Shell structure and magic numbers in atomic nuclei were generally explained by pioneering work that introduced a strong spin-orbit interaction to the nuclear shell model potential. However, knowledge of nuclear forces and the mechanisms governing the structure of nuclei, in particular far from stability, is still incomplete. In nuclei with equal neutron and proton numbers (N = Z), enhanced correlations arise between neutrons and protons (two distinct types of fermions) that occupy orbitals with the same quantum numbers. Such correlations have been predicted to favour an unusual type of nuclear superfluidity, termed isoscalar neutron-proton pairing, in addition to normal isovector pairing. Despite many experimental efforts, these predictions have not been confirmed. Here we report the experimental observation of excited states in the N = Z = 46 nucleus (92)Pd. Gamma rays emitted following the (58)Ni((36)Ar,2n)(92)Pd fusion-evaporation reaction were identified using a combination of state-of-the-art high-resolution γ-ray, charged-particle and neutron detector systems. Our results reveal evidence for a spin-aligned, isoscalar neutron-proton coupling scheme, different from the previous prediction. We suggest that this coupling scheme replaces normal superfluidity (characterized by seniority coupling) in the ground and low-lying excited states of the heaviest N = Z nuclei. Such strong, isoscalar neutron-proton correlations would have a considerable impact on the nuclear level structure and possibly influence the dynamics of rapid proton capture in stellar nucleosynthesis.

Crumpled-to-tubule transition in anisotropic polymerized membranes: beyond the ϵ expansion.

Anisotropic D-dimensional polymerized phantom membranes are investigated within a nonperturbative renormalization group framework. One focuses on the transition between a high-temperature, crumpled phase and a low-temperature, tubular phase where the membrane is flat along one direction and crumpled along the other ones. While the upper critical dimension--D(uc)=5/2--is close to D=2, the weak-coupling perturbative approach is qualitatively and quantitatively wrong. We show that our approach is free of the problems encountered within the perturbative framework and provides physically meaningful critical quantities.

Universal behaviors in the wrinkling transition of disordered membranes.

The wrinkling transition experimentally identified by Mutz et al. [Phys. Rev. Lett. 67, 923 (1991)PRLTAO0031-900710.1103/PhysRevLett.67.923] and then thoroughly studied by Chaieb et al. [Phys. Rev. Lett. 96, 078101 (2006)]PRLTAO0031-900710.1103/PhysRevLett.96.078101 in partially polymerized lipid membranes is reconsidered. One shows that the features associated with this transition, notably the various scaling behaviors of the height-height correlation functions that have been observed, are qualitatively and quantitatively well described by a recent nonperturbative renormalization group approach to quenched disordered membranes by Coquand et al. [Phys. Rev E 97, 030102(R) (2018)]2470-004510.1103/PhysRevE.97.030102. As these behaviors are associated with fixed points of renormalization group transformations they are universal and should also be observed in, e.g., defective graphene and graphene-like materials.

Crumpling transition and flat phase of polymerized phantom membranes.

Polymerized phantom membranes are revisited using a nonperturbative renormalization-group approach. This allows one to investigate both the crumpling transition and the low-temperature flat phase in any internal dimension D and embedding dimension d and to determine the lower critical dimension. The crumpling phase transition for physical membranes is found to be of second order within our approximation. A weak first-order behavior, as observed in recent Monte Carlo simulations, is however not excluded.

Site percolation on planar Phi(3) random graphs.

In this paper, site percolation on random Phi(3) planar graphs is studied by Monte Carlo numerical techniques. The method consists in randomly removing a fraction q = 1-p of vertices from graphs generated by Monte Carlo simulations, where p is the occupation probability. The resulting graphs are made of clusters of occupied sites. By measuring several properties of their distribution, it is shown that percolation occurs for an occupation probability above a percolation threshold p(c) = 0.7360(5) . Moreover, critical exponents are compatible with those analytically known for bond percolation.

Glassy phase in quenched disordered crystalline membranes.

We investigate the flat phase of D-dimensional crystalline membranes embedded in a d-dimensional space and submitted to both metric and curvature quenched disorders using a nonperturbative renormalization group approach. We identify a second-order phase transition controlled by a finite-temperature, finite-disorder fixed point unreachable within the leading order of ε=4-D and 1/d expansions. This critical point divides the flow diagram into two basins of attraction: that associated with the finite-temperature fixed point controlling the long-distance behavior of disorder-free membranes and that associated with the zero-temperature, finite-disorder fixed point. Our work thus strongly suggests the existence of a whole low-temperature glassy phase for quenched disordered crystalline membranes and, possibly, for graphene and graphene-like compounds.

Long-term storage of frozen lenticules for cryorefractive surgery.

We studied freezing rates, cryoprotectants, and storage times on keratocyte viability, using rabbit corneal buttons incubated in either KM-26, CPTES, K-Sol, or TC 199 for 30 minutes at 4 degrees C. Using a controlled freezing rate (2 degrees/min to -40 degrees C), viabilities were 69 +/- 7% for KM-26, 113 +/- 21% for CPTES, 0.1 +/- 0.08% for K-Sol, and 0 +/- 0% for TC 199. The KM-26 and CPTES were further studied in corneas stored one to 30 days at -80 or -196 degrees C; CPTES had a better cryoprotective efficacy over one, three, and seven days of -80 degrees storage, and at liquid nitrogen storage temperature (-196 degrees) over one, 14, and 30 days storage. The findings demonstrate the superiority of CPTES. It provides better viability than KM-26 under similar conditions, and may enable long-term frozen storage of lenticules for later use in cryorefractive surgeries, with minimal loss of keratocyte viability.

First-order transition of tethered membranes in three-dimensional space.

We study a model of phantom tethered membranes, embedded in three-dimensional space, by extensive Monte Carlo simulations. The membranes have hexagonal lattice structure where each monomer is interacting with six nearest-neighbors (NN). Tethering interaction between NN, as well as curvature penalty between NN triangles are taken into account. This model is new in the sense that NN interactions are taken into account by a truncated Lennard-Jones potential including both repulsive and attractive parts. The main result of our study is that the system undergoes a first-order crumpling transition from low-temperature flat phase to high-temperature crumpled phase, in contrast with early numerical results on models of tethered membranes.

First-order phase transitions in polymerized phantom membranes.

The crumpled-to-flat phase transition that occurs in D-dimensional polymerized phantom membranes embedded in a d-dimensional space is investigated nonperturbatively using a field expansion up to order 8 in powers of the order parameter. We get the critical dimension dcr(D) that separates a second-order region from a first-order one everywhere between D=4 and 2. Our approach strongly suggests that the phase transitions that take place in physical membranes are of first order in agreement with most recent numerical simulations.

University of Lodz an electron spectrometer--a new conversion-electron spectrometer for "in-beam" measurements.

The designed and constructed at the University of Lodz an electron spectrometer is devoted to "in-beam" measurements. The apparatus is characterized by high efficiency up to 9%, good energy resolution (FWHM = 5 keV at 482 keV) and, what is very important good suppression of delta electrons, positrons, and photons emitted by the targets. This achievement was obtained using a combination of magnetic field in two different layouts: perpendicular and parallel to the axis of the spectrometer being orthogonal to the beamline. The conversion-electron spectrometer coupled to the EAGLE array was successfully tested in an "in-beam" measurement.

Decay chains and photofission investigation based on nuclear spectroscopy of highly enriched uranium sample.

Nuclear spectroscopy experiments were performed for 100g metallic uranium rod enriched to 93% (235)U, in order to establish and characterize the most prominent γ-rays in the natural decay series and photofission reaction. Single γ-ray spectra and γ-γ coincidences measurements were conducted before irradiation. The uranium sample was subsequently irradiated with 15 MeV bremsstrahlung photons. Relative intensities of γ-lines and several values of half-lives of the fission fragments decays were determined. The obtained information can be utilized in detection of smuggled nuclear materials and characterization of bulky nuclear waste packages.

128Cs as the best example revealing chiral symmetry breaking.

The results of the Doppler-shift attenuation method lifetime measurements in partner bands of 128Cs and 132La are presented. Experimental reduced transition probabilities in 128Cs are compared with theoretical calculations done in the frame of the core-quasiparticle coupling model. The electromagnetic properties, energy and spin of levels belonging to the partner bands show that 128Cs is the best known example revealing the chiral symmetry breaking phenomenon.

[Sutureless phacotrabeculectomy. Interim results]. / Phakotrabekulektomie ohne Naht. Mittelfristige Ergebnisse.

BACKGROUND: To study the medium-term success rate of a simple surgical technique for combined operation of cataract and glaucoma. MATERIALS AND METHODS: Of 50 patients with cataract and various types of glaucoma, 55 eyes underwent a combined operation for cataract and glaucoma and were followed up for at least 6.5 months. The phacoemulsification war performed through a scleral tunnel. After implantation of a foldable IOL an "inverse T" incision of the tunnel floor was performed to create a valve mechanism closure. RESULTS: In 45 eyes (83%) the intraocular pressure was controlled without medications during the follow-up time. In 10 cases (17%) a new glaucoma medication was introduced postoperatively. Following early postoperative complications were noticed: early intraocular hypertension (20.0%), wound leakage (20.0%), early intraocular hypotension (10.9%), hyphema (19.1%). CONCLUSIONS: No-stitch phacotrabeculectomy appears to be a safe and (medium-term) effective procedure for combined surgery of cataract and glaucoma.