Classical-path integral adaptive resolution in molecular simulation: towards a smooth quantum-classical coupling

Simulations that couple different classical molecular models in an adaptive way by changing the number of degrees of freedom on the fly, are available within reasonably consistent theoretical frameworks. The same does not occur when it comes to classical-quantum adaptivity. The main reason for this is the difficulty in describing a continuous transition between the two different kind of physical principles: probabilistic for the quantum and deterministic for the classical. Here we report the basic principles of an algorithm that allows for a continuous and smooth transition by employing the path integral description of atoms.Comment: 8 pages 4 figure

The Solar Neutrino Day/Night Effect in Super-Kamiokande

The time variation of the elastic scattering rate of solar neutrinos with electrons in Super-Kamiokande-I was fit to the day/night variations expected from active two-neutrino oscillations in the Large Mixing Angle region. Combining Super-Kamiokande measurements with other solar and reactor neutrino data, the mixing angle is determined as sin^2theta=0.276+0.033-0.026 and the mass squared difference between the two neutrino mass eigenstates as Delta m^2=7.1+0.6-0.5x10^-5eV^2. For the best fit parameters, a day/night asymmetry of -1.7+-1.6(stat)+1.3-1.2(syst)% was determined from the Super-Kamiokande data, which has improved statistical precision over previous measurements and is in excellent agreement with the expected value of -1.6%.Comment: 3 pages, 4 figures; to appear in the proceedings of the TAUP 2003 conferenc

Transient effects in fission evidenced from new experimental signatures

A new experimental approach is introduced to investigate the relaxation of the nuclear deformation degrees of freedom. Highly excited fissioning systems with compact shapes and low angular momenta are produced in peripheral relativistic heavy-ion collisions. Both fission fragments are identified in atomic number. Fission cross sections and fission-fragment element distributions are determined as a function of the fissioning element. From the comparison of these new observables with a nuclear-reaction code a value for the transient time is deduced.Comment: 6 pages, 2 figures, background information at http://www-w2k.gsi.de/kschmidt

Production of new neutron-rich isotopes of heavy elements in fragmentation reactions of 238^{238}U projectiles at 1 A GeV

The production of heavy neutron-rich nuclei has been investigated using cold fragmentation reactions of $^{238}$U projectiles at relativistic energies. The experiment performed at the high-resolving-power magnetic spectrometer FRS at GSI allowed to identify 45 new heavy neutron-rich nuclei: $^{205}$Pt, $^{207-210}$Au, $^{211-216}$Hg, $^{213-217}$Tl, $^{215-220}$Pb, $^{219-224}$Bi, $^{221-227}$Po, $^{224-229}$At, $^{229-231}$Rn and $^{233}$Fr. The production cross sections of these nuclei were also determined and used to benchmark reaction codes that predict the production of nuclei far from stability.Comment: 5 pages, 2 figure

Situação e perspectivas da abacaxicultura no Amazonas.

Na região Amazônica ocorrem muitos tipos silvestres de abacaxizeiro em habitats naturais e diversas cultivares locais são plantadas em pequena escala por agricultores familiares para consumo e comercialização local. No Amazonas, a variedade denominada Turiaçu é predominante nos cultivos. Presume-se que esta variedade tenha sido trazida da região de Turiaçu, no Maranhão. As características botânicas e agronômicas são muito semelhantes entre as populações de abacaxizeiro cultivadas nos municípios de Turiaçu, MA e Itacoatiara, AM. Até o momento, sintomas de fusariose (Fusarium guttiforme), a principal doença do abacaxizeiro, não foram observados para a variedade Turiaçu, no Amazonas e Maranhão. Esta variedade ainda foi pouco estudada em seus aspectos agronômicos, como exigências nutricionais, indução floral e produção de mudas. No Amazonas, o cultivo do abacaxi Turiaçu já tem sido feito com uso de tecnologias básicas, tais como, plantio em fileiras duplas, aplicação de indutores florais, preparo do solo e adubação química, baseando-se no sistema de produção já estabelecido para a cultivar Pérola. Estima-se que em 80 a 85% da área cultivada no estado do Amazonas seja utilizada a variedade Turiaçu. A produção de abacaxi no Amazonas cresceu em 63% de 2004 para 2011, e atualmente o estado é o oitavo maior produtor do país. Esta produção se concentra no município de Itacoatiara, sobretudo nas regiões de Novo Remanso e Vila do Engenho

Development of a novel approach to the assessment of eye-hand coordination

Background Current methods to measure eye–hand coordination (EHC) have been widely applied in research and practical fields. However, some aspects of the methods, such as subjectivity, high price, portability, and high appraisal contribute to difficulties in EHC testing. New methods The test was developed on an Apple iPad® and involves tracing up to 13 shapes with a stylus pen. The time taken to complete each trace and the spatial accuracy of the tracing is automatically recorded. The difficulty level for each shape was evaluated theoretically based on the complexity and length of outline. Ten adults aged 31.5 ± 7.8 years and five children aged 9.4 ± 1.1 years with normal vision participated. Results In adults, the time taken to trace and number of errors significantly decreased from the first to the second attempt (p < 0.05) but not thereafter, suggesting a learning effect with repeatability after a practice attempt. Time taken and number of errors in children were both higher in monocular than binocular viewing conditions (p = 0.02 and p < 0.01, respectively) while adults’ performance was similar in both viewing conditions. Comparison with existing methods Existing EHC tests are subjective in clinics and require higher skills and cost in research, and measure gross EHC. This novel test has been developed to address some of the limitations. Conclusions The test is engaging for children and adults and is an objective method with potential for the assessment of fine EHC, suited to clinic-based and research use in ophthalmic or brain trauma settings, and in developmental disorders

Total Photoabsorption Cross Sections of A=6 Nuclei with Complete Final State Interaction

The total photoabsorption cross sections of 6He and 6Li are calculated microscopically with full inclusion of the six-nucleon final state interaction using semirealistic nucleon-nucleon potentials. The Lorentz Integral Transform (LIT) method and the effective interaction approach for the hyperspherical formalism are employed. While 6Li has a single broad giant resonance peak, there are two well separated peaks for 6He corresponding to the breakup of the neutron halo and the alpha core, respectively. The comparison with the few available experimental data is discussed.Comment: LaTeX, 8 pages, 3 ps figure

Progress of the Felsenkeller shallow-underground accelerator for nuclear astrophysics

Low-background experiments with stable ion beams are an important tool for putting the model of stellar hydrogen, helium, and carbon burning on a solid experimental foundation. The pioneering work in this regard has been done by the LUNA collaboration at Gran Sasso, using a 0.4 MV accelerator. In the present contribution, the status of the project for a higher-energy underground accelerator is reviewed. Two tunnels of the Felsenkeller underground site in Dresden, Germany, are currently being refurbished for the installation of a 5 MV high-current Pelletron accelerator. Construction work is on schedule and expected to complete in August 2017. The accelerator will provide intense, 50 uA, beams of 1H+, 4He+, and 12C+ ions, enabling research on astrophysically relevant nuclear reactions with unprecedented sensitivity.Comment: Submitted to the Proceedings of Nuclei in the Cosmos XIV, 19-24 June 2016, Niigata/Japa

Constraints on Neutrino Parameters from Neutral-Current Solar Neutrino Measurements

We generalize the pull approach to define the $\chi^2$ function to the analysis of the data with correlated statistical errors. We apply this method to the analysis of the Sudbury Neutrino Collaboration data obtained in the salt-phase. In the global analysis of all the solar neutrino and KamLAND data we find the best fit (minimum $\chi^2$) values of neutrino parameters to be $\tan^2 \theta_{12} \sim 0.42$ and $\delta m_{12}^2 \sim 7.1 \times 10^{-5}$ eV$^2$. We confirm that the maximal mixing is strongly disfavored while the bounds on $\delta m_{12}^2$ are significantly strengthened.Comment: 6 figures. Some typos are corrected, figures are visually improve