326 research outputs found

    Neutron Transfer Dynamics and Doorway to Fusion in Time-Dependent Hartree-Fock Theory

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    We analyze the details of mass exchange in the vicinity of the Coulomb barrier for heavy-ion collisions involving neutron-rich nuclei using the time-dependent Hartree-Fock (TDHF) theory. We discuss the time-dependence of transfer and show that the potential barriers seen by individual single-particle states can be considerably different than the effective barrier for the two interacting nuclei having a single center-of-mass. For this reason we observe a substantial transfer probability even at energies below the effective barrier.Comment: 6 pages, 9 figure

    Генетическая гетерогенность и некоторые другие проблемы, осложняющие диагностику наследственных болезней нервной системы

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    A hereditary disorders of the nervous system is one of the largest group of human monogenic disorders with high-grade genetic heterogeneity and clinical polymorphism. The main types of genetic heterogeneity and their possible causes are explained by giving typical examples of different nosological forms. The basic problems and feasible solution of medico-genetic counseling and education of high-risk families in case of genetic heterogeneity are discussed.Наследственные болезни нервной системы — одна из наиболее многочисленных групп моногенной патологии человека, характеризующаяся выраженной генетической гетерогенностью и клиническим полиморфизмом. В статье определены основные типы генетической гетерогенности и на примерах отдельных нозологических форм этой группы заболеваний предположены причины ее возникновения. Обозначены проблемы, создаваемые генетической гетерогенностью, при проведении медико-генетического консультирования отягощенных семей и предложены способы их решения

    Beta-decay of nuclei around Se-90. Search for signatures of a N=56 sub-shell closure relevant the r-process

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    Nuclear structure plays a significant role on the rapid neutron capture process (r-process) since shapes evolve with the emergence of shells and sub-shells. There was some indication in neighboring nuclei that we might find examples of a new N=56 sub-shell, which may give rise to a doubly magic Se-90 nucleus. Beta-decay half lives of nuclei around Se-90 have been measured to determine if this nucleus has in fact a doubly-magic character. The fragmentation of Xe-136 beam at the National Superconducting Cyclotron Laboratory at Michigan State University was used to create a cocktail of nuclei in the A=90 region. We have measured the half lives of twenty-two nuclei near the r-process path in the A=90 region. The half lives of As-88 and Se-90 have been measured for the first time. The values were compared with theoretical predictions in the search for nuclear-deformation signatures of a N=56 sub-shell, and its possible role in the emergence of a potential doubly-magic Se-90. The impact of such hypothesis on the synthesis of heavy nuclei, particularly in the production of Sr, Y and Zr elements was investigated with a weak r-process network. The new half lives agree with results obtained from a standard global QRPA model used in r-process calculations, indicating that Se-90 has a quadrupole shape incompatible with a closed N=56 sub-shell in this region. The impact of the measured Se-90 half-life in comparison with a former theoretical predication associated with a spherical half-life on the weak-r-process is shown to be strong

    Cross Section Limits for the 208^{208}Pb(86^{86}Kr,n)293^{293}118 Reaction

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    In April-May, 2001, the previously reported experiment to synthesize element 118 using the 208^{208}Pb(86^{86}Kr,n)293^{293}118 reaction was repeated. No events corresponding to the synthesis of element 118 were observed with a total beam dose of 2.6 x 1018^{18} ions. The simple upper limit cross sections (1 event) were 0.9 and 0.6 pb for evaporation residue magnetic rigidities of 2.00 TmT m and 2.12 TmT m, respectively. A more detailed cross section calculation, accounting for an assumed narrow excitation function, the energy loss of the beam in traversing the target and the uncertainty in the magnetic rigidity of the Z=118 recoils is also presented. Re-analysis of the primary data files from the 1999 experiment showed the reported element 118 events are not in the original data. The current results put constraints on the production cross section for synthesis of very heavy nuclei in cold fusion reactions.Comment: 7 pages, 2 figures. Submitted to EPJ

    Beta-delayed proton emission in the 100Sn region

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    Beta-delayed proton emission from nuclides in the neighborhood of 100Sn was studied at the National Superconducting Cyclotron Laboratory. The nuclei were produced by fragmentation of a 120 MeV/nucleon 112Sn primary beam on a Be target. Beam purification was provided by the A1900 Fragment Separator and the Radio Frequency Fragment Separator. The fragments of interest were identified and their decay was studied with the NSCL Beta Counting System (BCS) in conjunction with the Segmented Germanium Array (SeGA). The nuclei 96Cd, 98Ing, 98Inm and 99In were identified as beta-delayed proton emitters, with branching ratios bp = 5.5(40)%, 5.5+3 -2%, 19(2)% and 0.9(4)%, respectively. The bp for 89Ru, 91,92Rh, 93Pd and 95Ag were deduced for the first time with bp = 3+1.9 -1.7%, 1.3(5)%, 1.9(1)%, 7.5(5)% and 2.5(3)%, respectively. The bp = 22(1)% for 101Sn was deduced with higher precision than previously reported. The impact of the newly measured bp values on the composition of the type-I X-ray burst ashes was studied.Comment: 15 pages, 14 Figures, 4 Table

    Whole exome sequencing links dental tumor to an autosomal-dominant mutation in ANO5 gene associated with gnathodiaphyseal dysplasia and muscle dystrophies

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    Tumors of the jaws may represent different human disorders and frequently associate with pathologic bone fractures. In this report, we analyzed two affected siblings from a family of Russian origin, with a history of dental tumors of the jaws, in correspondence to original clinical diagnosis of cementoma consistent with gigantiform cementoma (GC, OMIM: 137575). Whole exome sequencing revealed the heterozygous missense mutation c.1067G \u3e A (p.Cys356Tyr) in ANO5 gene in these patients. To date, autosomal-dominant mutations have been described in the ANO5 gene for gnathodiaphyseal dysplasia (GDD, OMIM: 166260), and multiple recessive mutations have been described in the gene for muscle dystrophies (OMIM: 613319, 611307); the same amino acid (Cys) at the position 356 is mutated in GDD. These genetic data and similar clinical phenotypes demonstrate that the GC and GDD likely represent the same type of bone pathology. Our data illustrate the significance of mutations in single amino-acid position for particular bone tissue pathology. Modifying role of genetic variations in another gene on the severity of the monogenic trait pathology is also suggested. Finally, we propose the model explaining the tissue-specific manifestation of clinically distant bone and muscle diseases linked to mutations in one gene

    BioInfer: a corpus for information extraction in the biomedical domain

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    BACKGROUND: Lately, there has been a great interest in the application of information extraction methods to the biomedical domain, in particular, to the extraction of relationships of genes, proteins, and RNA from scientific publications. The development and evaluation of such methods requires annotated domain corpora. RESULTS: We present BioInfer (Bio Information Extraction Resource), a new public resource providing an annotated corpus of biomedical English. We describe an annotation scheme capturing named entities and their relationships along with a dependency analysis of sentence syntax. We further present ontologies defining the types of entities and relationships annotated in the corpus. Currently, the corpus contains 1100 sentences from abstracts of biomedical research articles annotated for relationships, named entities, as well as syntactic dependencies. Supporting software is provided with the corpus. The corpus is unique in the domain in combining these annotation types for a single set of sentences, and in the level of detail of the relationship annotation. CONCLUSION: We introduce a corpus targeted at protein, gene, and RNA relationships which serves as a resource for the development of information extraction systems and their components such as parsers and domain analyzers. The corpus will be maintained and further developed with a current version being available at

    Cross-country evidence on the social determinants of the post-socialist mortality crisis in Europe: a review and performance-based hierarchy of variables.

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    An unprecedented mortality crisis befell the former socialist countries between 1989 and 1995, representing one of the greatest demographic shocks of the period after the Second World War. While it is likely that country-level variation in the post-socialist mortality crisis in Eastern Europe can be explained by a constellation of political and socio-economic factors, no comprehensive review of the existing scholarly attempts at explaining these factors exists. We review 39 cross-national multi-variable peer reviewed studies of social determinants of mortality in post-socialist Europe in order to assess the social factors behind the post-socialist mortality crisis, determine the gaps in the existing literature and to make suggestions for future research. We propose a novel methodology to determine the relative importance of variables based on the ratio of significant to insignificant findings for each variable. The literature identifies inequality, welfare payments, religious composition, democracy, economic performance and unemployment as the leading factors that have a significant influence on mortality outcomes. Existing cross-country studies fail to establish a definitive connection between mortality and diets, drinking patterns, liberalisation, trust, health expenditure and war. We also point out that the level of analysis is not a neutral methodological choice but might influence the results themselves

    Particle-hole excited states in 133 Te

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    Excited states in neutron-rich 133Te{}^{133}\mathrm{Te} have been identified with the Gamma sphere array by measuring three- and higher-fold prompt coincidence events following spontaneous fission of 252Cf.{}^{252}\mathrm{Cf}. Four types of particle-hole bands built on the known 334.3 keV isomer in 133Te{}^{133}\mathrm{Te} are identified. The yrast and near yrast particle-hole states observed up to 6.2 MeV in 133Te{}^{133}\mathrm{Te} have characteristics quite similar to those in 134Te.{}^{134}\mathrm{Te}. These states are interpreted as a result of coupling a neutron \ensuremath{\nu}{h}_{11/2} hole to the 134Te{}^{134}\mathrm{Te} core. The group of states observed above 5.214 MeV is the result of a neutron particle-hole excitation of the double magic core nucleus 132Sn,{}^{132}\mathrm{Sn}, and is a candidate for a tilted rotor band. Shell-model calculations considering 132Sn{}^{132}\mathrm{Sn} as a closed core have been performed and have provided guidance to the interpretation of the levels below 4.3 MeV. Very good agreement between theory and experiment is obtained for these states
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