Doubly magic nuclei from Lattice QCD forces at MPS=M_{PS}=469 MeV/c2^2

We perform ab initio self-consistent Green's function calculations of the closed shell nuclei $^{\rm 4}$He, $^{\rm 16}$O and $^{\rm 40}$Ca, based on two-nucleon potentials derived from Lattice QCD simulations, in the flavor SU(3) limit and at the pseudo-scalar meson mass of 469~MeV/c$^{\rm 2}$. The nucleon-nucleon interaction is obtained using the HAL QCD method and its short-distance repulsion is treated by means of ladder resummations outside the model space. Our results show that this approach diagonalises ultraviolet degrees of freedom correctly. Therefore, ground state energies can be obtained from infrared extrapolations even for the relatively hard potentials of HAL QCD. Comparing to previous Brueckner Hartree-Fock calculations, the total binding energies are sensibly improved by the full account of many-body correlations. The results suggest an interesting possible behaviour in which nuclei are unbound at very large pion masses and islands of stability appear at first around the traditional doubly-magic numbers when the pion mass is lowered toward its physical value. The calculated one-nucleon spectral distributions are qualitatively close to those of real nuclei even for the pseudo-scalar meson mass considered here.Comment: 7 pages, 4 figures, RIKEN-QHP-286, RIKEN-iTHEMS-Report-1

Regimes of polymer behaviour in drop-on-demand ink-jetting

Three regimes of fast DoD jetting behaviour for solutions of mono-disperse linear polymers have been linked to the underlying polymer molecular chains and their fully extended length L in good solvents. This allows scaling laws in molecular weight to be predicted and applied to experimental jetting results from different DoD print heads. The higher extensional flows encountered in high speed jetting in viscous solvents can fully stretch linear molecules outside the nozzle, permitting jetting of higher polymer content than for purely elastic behaviour. These results are significant for DoD printing at raised jet speeds and will apply to any DoD print head jetting linear polymer solutions.This work was supported by EPSRC grant number RG5560

Radical political unionism reassessed

Defections from European social-democratic parties and a resurgence of union militancy have prompted some to diagnose a new left-wing trade unionism across Europe. This comment on the article by Connolly and Darlington scrutinizes trends in France and Germany but primarily analyses recent developments in Britain. While there are some instances of disaffiliation from the Labour Party, support for electoral alternatives, growth in political militancy and emphasis on new forms of internationalism, these have been limited. There is insufficient evidence to suggest that we are witnessing the making of a new radical collectivism

Complex inkjets: particles, polymers and non-linear driving

Can inkjet technology revolutionise manufacturing processes as we know them? By extending the existing benefits of inkjet methods to attain the speed, coverage and material diversity of conventional printing, we can transform inkjet from its present status as a niche technology into a mainstream process, with the UK as a major player. However, we require a better understanding of the science underlying the formation of small droplets and the effect of complex additives. First, we highlight key inkjetting methods and discuss well-known effects that particles and polymers have on jet evolution. We describe how jetting and filament-thinning experiments can be used to measure key characterisation parameters and how these techniques can be modelled via an established simulation method. Second, we review the literature exploring jet stability and break-up, including the Rayleigh stability analysis and universal self-similar thinning laws. In Chapter 3, we develop a simple one-dimensional model. First, we model particulate effects on the decay of a liquid bridge and identify three thinning regimes. In particular, we describe a mechanism for acceleration, which agrees quantitatively with experiments. In contrast, the addition of viscoelasticity retards thinning processes and delays break-up. Our viscoelastic jetting model demonstrates the theoretical exponential thinning law, `beads-on-string' structures and is in quantitative agreement with axisymmetric simulations. In Chapter 4, we develop a simplified drop-on-demand jetting model to predict the printability of polymer solutions. We demonstrate three known jetting regimes and the predicted `jettable' concentration threshold is in quantitative agreement with experimental data. Using axisymmetric simulations, we identify a `pre-stretch' mechanism that is able to fully extend polymers within the nozzle. Consequently, we show that molecules can undergo central scission due to high strain rates at the nozzle exit. In Chapter 5, we simulate a one-dimensional continuous inkjet using an adaptive mesh technique. We explore non-linear behaviour caused by finite-amplitude modulations in the driving velocity profile, where jet stability deviates from Rayleigh behaviour. We identify a modulation range where pinching becomes `inverted', occurring upstream of the filament connecting the main drops, rather than downstream. This behaviour can be controlled by the addition of a second harmonic to the initial driving signal. Our results are compared to full axisymmetric simulations in order to incorporate the effects of nozzle geometry

PolySTRAND Model of Flow-Induced Nucleation in Polymers

We develop a thermodynamic continuum-level model, polySTRAND, for flow-induced nucleation in polymers suitable for use in computational process modeling. The model’s molecular origins ensure that it accounts properly for flow and nucleation dynamics of polydisperse systems and can be extended to include effects of exhaustion of highly deformed chains and nucleus roughness. It captures variations with the key processing parameters, flow rate, temperature, and molecular weight distribution. Under strong flow, long chains are over-represented within the nucleus, leading to superexponential nucleation rate growth with shear rate as seen in experiments

Even faster sorting of (not only) integers

In this paper we introduce RADULS2, the fastest parallel sorter based on radix algorithm. It is optimized to process huge amounts of data making use of modern multicore CPUs. The main novelties include: extremely optimized algorithm for handling tiny arrays (up to about a hundred of records) that could appear even billions times as subproblems to handle and improved processing of larger subarrays with better use of non-temporal memory stores

Confirming the metazoan character of a 565Ma trace-fossil assemblage from Mistaken Point, Newfoundland

Surface locomotory trace fossils from the Mistaken Point Formation of Newfoundland, dated at ∼ 565 Ma, suggest that organisms capable of controlled locomotion and possessing muscular tissue may have existed among Avalonian Ediacaran macrofossil assemblages. Here we describe the Mistaken Point trace-fossil assemblage in full, discuss its stratigraphic context within the Mistaken Point Formation, and explore the competing hypotheses for the formation of the traces. We find that the trace fossils, preserved within a turbidite succession in a deep-marine depositional environment, are not attributable to abiogenic structures, to Ediacaran tubular or filamentous body fossils, to rangeomorph stems, or to a host of late Ediacaran and early Phanerozoic ichnofossils. Specimens within the assemblage show some similarities to the ichnogenera Helminthoidichnites and Archaeonassa, but discrepancies in certain aspects of their structure mean that we do not formally attribute them to these ichnotaxa at this time. The Mistaken Point ichnofossils possess morphological characteristics indicative of formation by an organism with a round base. Comparison with traces formed by modern organisms of such character appears to rule out formation by protistan, echinoderm, or annelid styles of movement, but is consistent with organisms moving via muscular controlled locomotion in a similar way to some modern mollusks and actinian cnidarians. We suggest therefore that the Mistaken Point trace-fossil assemblage reveals the presence of muscular metazoans in late Ediacaran deep-marine ecosystems. Such organisms cannot yet be attributed to specific phyla, but their inferred locomotory mechanisms share closest similarities with those utilized by extant actinians

P18-01. Exquisite specificity of CTL response to the M184V mutation

International audiencen.

Atypically diffuse functional connectivity between caudate nuclei and cerebral cortex in autism

BACKGROUND: Autism is a neurodevelopmental disorder affecting sociocommunicative behavior, but also sensorimotor skill learning, oculomotor control, and executive functioning. Some of these impairments may be related to abnormalities of the caudate nuclei, which have been reported for autism. METHODS: Our sample was comprised of 8 high-functioning males with autism and 8 handedness, sex, and age-matched controls. Subjects underwent functional MRI scanning during performance on simple visuomotor coordination tasks. Functional connectivity MRI (fcMRI) effects were identified as interregional blood oxygenation level dependent (BOLD) signal cross-correlation, using the caudate nuclei as seed volumes. RESULTS: In the control group, fcMRI effects were found in circuits with known participation of the caudate nuclei (associative, orbitofrontal, oculomotor, motor circuits). Although in the autism group fcMRI effects within these circuits were less pronounced or absent, autistic subjects showed diffusely increased connectivity mostly in pericentral regions, but also in brain areas outside expected anatomical circuits (such as visual cortex). CONCLUSION: These atypical connectivity patterns may be linked to developmental brain growth disturbances recently reported in autism and suggest inefficiently organized functional connectivity between caudate nuclei and cerebral cortex, potentially accounting for stereotypic behaviors and executive impairments