Hoyle state and rotational features in Carbon-12 within a no-core shell model framework

By using only a fraction of the model space extended beyond current no-core shell-model limits and a schematic effective many-nucleon interaction, we gain additional insight within a symmetry-guided shell-model framework, into the many-body dynamics that gives rise to the ground state rotational band together with phenomena tied to alpha-clustering substructures in the low-lying states in C-12, and in particular, the challenging Hoyle state and its first 2+ excitation. For these states, we offer a novel perspective emerging out of no-core shell-model considerations, including a discussion of associated nuclear shapes and matter radii. This, in turn, provides guidance for ab initio shell models by informing key features of nuclear structure and the interaction.Comment: 5 pages, 4 figure

Differences in the compatibility of infection between the liver flukes Fascioloides magna and Fasciola hepatica in a Colombian population of the snail Galba sp.

Experimental infections of Galba sp. (origin, Colombia) with allopatric isolates of Fasciola hepatica from France or Fascioloides magna from the Czech Republic were carried out during five successive snail generations to determine if this lymnaeid might sustain complete larval development of either parasite. In snails exposed to F. hepatica, 7 of 400 snails harboured several rediae and only two snails contained a small number of free cercariae on day 50 post-exposure. In contrast, the intensity of F. magna infection in Galba sp. progressively increased from the F1 to F5 generations. Spontaneous cercarial shedding of F. magna occurred in 7 of 100 Galba sp. belonging to the F5 generation and the number of shed cercariae did not differ significantly from that noted in control Galba truncatula of French origin. Galba sp. from Colombia can be added to the list of potential intermediate hosts for F. magna

HUMAN PARAGONIMIASIS IN AFRICA

An up-to-date review on human paragonimiasis in Africa was carried out to determine the current geographical distribution of human cases and analyze the animal reservoir, snails and crustaceans which intervene in the local life cycle of Paragonimus species. Two countries, i.e., Cameroon and Nigeria, were mainly affected by this disease, while the distribution of human cases in the other eight states of the intertropical zone was scattered. Infected patients were currently few in number and two Paragonimus species: P. africanus and P. uterobilateralis, were found. The animal reservoir is mainly constituted by crab-eating mammals. The identity of the host snail remains doubtful and was either a prosobranch, or a land snail. Seven crab species belonging to Callinectes, Liberonautes and Sudanonautes genera are able to harbour paragonimid metacercariae. Due to the current low prevalence of human paragonimiasis recorded in Africa and the high cost of wide-scale screenings for this disease, training of technicians in anti-tuberculosis centers would be the most realistic attitude to detect mycobacteria and/or Paragonimus eggs during the same sputum examinatio

Symplectic No-core Shell-model Approach to Intermediate-mass Nuclei

We present a microscopic description of nuclei in an intermediate-mass region, including the proximity to the proton drip line, based on a no-core shell model with a schematic many-nucleon long-range interaction with no parameter adjustments. The outcome confirms the essential role played by the symplectic symmetry to inform the interaction and the winnowing of shell-model spaces. We show that it is imperative that model spaces be expanded well beyond the current limits up through fifteen major shells to accommodate particle excitations that appear critical to highly-deformed spatial structures and the convergence of associated observables.Comment: 9 pages, 8 figure

Meta-analysis of glioblastoma multiforme versus anaplastic astrocytoma identifies robust gene markers

<p>Abstract</p> <p>Background</p> <p>Anaplastic astrocytoma (AA) and its more aggressive counterpart, glioblastoma multiforme (GBM), are the most common intrinsic brain tumors in adults and are almost universally fatal. A deeper understanding of the molecular relationship of these tumor types is necessary to derive insights into the diagnosis, prognosis, and treatment of gliomas. Although genomewide profiling of expression levels with microarrays can be used to identify differentially expressed genes between these tumor types, comparative studies so far have resulted in gene lists that show little overlap.</p> <p>Results</p> <p>To achieve a more accurate and stable list of the differentially expressed genes and pathways between primary GBM and AA, we performed a meta-analysis using publicly available genome-scale mRNA data sets. There were four data sets with sufficiently large sample sizes of both GBMs and AAs, all of which coincidentally used human U133 platforms from Affymetrix, allowing for easier and more precise integration of data. After scoring genes and pathways within each data set, we combined the statistics across studies using the nonparametric rank sum method to identify the features that differentiate GBMs and AAs. We found >900 statistically significant probe sets after correction for multiple testing from the >22,000 tested. We also used the rank sum approach to select >20 significant Biocarta pathways after correction for multiple testing out of >175 pathways examined. The most significant pathway was the hypoxia-inducible factor (HIF) pathway. Our analysis suggests that many of the most statistically significant genes work together in a <it>HIF1A</it>/<it>VEGF</it>-regulated network to increase angiogenesis and invasion in GBM when compared to AA.</p> <p>Conclusion</p> <p>We have performed a meta-analysis of genome-scale mRNA expression data for 289 human malignant gliomas and have identified a list of >900 probe sets and >20 pathways that are significantly different between GBM and AA. These feature lists could be utilized to aid in diagnosis, prognosis, and grade reduction of high-grade gliomas and to identify genes that were not previously suspected of playing an important role in glioma biology. More generally, this approach suggests that combined analysis of existing data sets can reveal new insights and that the large amount of publicly available cancer data sets should be further utilized in a similar manner.</p

Dominant Modes in Light Nuclei - Ab Initio View of Emergent Symmetries

An innovative symmetry-guided concept is discussed with a focus on emergent symmetry patterns in complex nuclei. In particular, the ab initio symmetry-adapted no-core shell model (SA-NCSM), which capitalizes on exact as well as partial symmetries that underpin the structure of nuclei, provides remarkable insight into how simple symmetry patterns emerge in the many-body nuclear dynamics from first principles. This ab initio view is complemented by a fully microscopic no-core symplectic shell-model framework (NCSpM), which, in turn, informs key features of the primary physics responsible for the emergent phenomena of large deformation and alpha-cluster substructures in studies of the challenging Hoyle state in Carbon-12 and enhanced collectivity in intermediate-mass nuclei. Furthermore, by recognizing that deformed configurations often dominate the low-energy regime, the SA-NCSM provides a strategy for determining the nature of bound states of nuclei in terms of a relatively small subspace of the symmetry-reorganized complete model space, which opens new domains of nuclei for ab initio investigations, namely, the intermediate-mass region, including isotopes of Ne, Mg, and Si

HPC-enabled nuclear structure studies-description and applications of the symmetry-adapted no-core shell model

By exploiting symmetries that enable the accounting of vital collective correlations in nuclei, we achieve significantly reduced dimensions for equivalent ultra-large model spaces, and hence resolve the scale explosion problem in nuclear structure calculations, i.e, the explosive growth in computational resource demands with increasing number of particles and size of the spaces in which they reside. As a result, we provide-with the help of High Performance Computing (HPC) resources-first solutions for selected benchmark calculations with remarkable findings of large-deformation and low-spin dominance in low-lying nuclear states. In the framework of a complementary symmetry-adapted study, one is able, facilitated by symmetry-preserving pieces of the inter-nucleon interaction, to accommodate unprecedented shell-model spaces critical to capture the physics governing the Hoyle state in 12C, thereby addressing a 60-year-old puzzle on the emergence of cluster substructures within a no-core shell model framework. All of these findings underline the key role of symmetries in nuclear structure studies

Microscopic description of the elusive Hoyle state

Within a symmetry-guided shell-model framework and using a fraction of the model space extended beyond current no-core shell-model limits along with a schematic effective many-nucleon interaction, we gain new insights into the many-body dynamics that give rise to the ground state and low-lying 0 + states of 12C and 16O. In particular, we gain further understanding of the alpha-clustering nature of the challenging Hoyle state and its first 2+ excitation in 12C, as well as the corresponding states in 16O. This provides guidance for ab initio shell models by informing key features of the underlying nuclear structure and interaction. © Published under licence by IOP Publishing Ltd

Symmetry-Adapted Ab Initio Open Core Shell Model Theory

By using only a fraction of the model space, we gain further insight - within a symmetry-guided no-core shell model framework - into the many-body nuclear dynamics that gives rise to important single-particle configurations together with correlated highly-deformed and alpha-cluster structures. We show results of the novel ab initio symmetry-adapted no-core shell model for large-scale nuclear structure computations. In addition, we use the symmetry patterns unveiled in these results to explore ultra-large model spaces. © Published under licence by IOP Publishing Ltd