909 research outputs found
Comment on "Electromagnetic dissociation of ^8B and the astrophysical S-factor for ^7Be(p,gamma)^8B"
Recently, Davids and Typel recommended a "low" value of S_{17}(0) based on
fits to published direct and Coulomb dissociation data, in which they excluded
the precise result of Junghans et al. We show that their statistical analysis
is incorrect, due to a substantial underestimate of the experimental
uncertainties, and leads to conclusions that are not supported by a proper
analysis.Comment: submitted to Phys. Rev.
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
IBI: Targeting cumulative coordination within an iterative protocol to derive coarse-grained models of (multi-component) complex fluids
We present a coarse-graining strategy that we test for aqueous mixtures. The
method uses pair-wise cumulative coordination as a target function within an
iterative Boltzmann inversion (IBI) like protocol. We name this method
coordination iterative Boltzmann inversion (IBI). While the
underlying coarse-grained model is still structure based and, thus, preserves
pair-wise solution structure, our method also reproduces solvation
thermodynamics of binary and/or ternary mixtures. Additionally, we observe much
faster convergence within IBI compared to IBI. To validate the
robustness, we apply IBI to study test cases of solvation
thermodynamics of aqueous urea and a triglycine solvation in aqueous urea
ParĂąmetros de qualidade de frutos de novos hĂbridos de abacaxizeiros desenvolvidos pela Embrapa Mandioca e Fruticultura.
O fruto do abacaxizeiro Ă© bastante apreciado e apresenta grande aceitação no mercado mundial em decorrĂȘncia de suas caracterĂsticas sensoriais e nutricionais. O programa de melhoramento genĂ©tico do abacaxizeiro da Embrapa Mandioca e Fruticultura desenvolve novos hĂbridos para atender Ă s expectativas deste mercado
Impacto potencial das mudanças climåticas sobre as doenças do abacaxi no Brasil.
O abacaxizeiro e o clima; Doenças causadas por fungos e oomicetos; Doença causada por vĂrus; Doença abiĂłtica
Statistical Mechanics of Aggregation and Crystallization for Semiflexible Polymers
By means of multicanonical computer simulations, we investigate thermodynamic
properties of the aggregation of interacting semiflexible polymers. We analyze
a mesoscopic bead-stick model, where nonbonded monomers interact via
Lennard-Jones forces. Aggregation turns out to be a process, in which the
constituents experience strong structural fluctuations, similar to peptides in
coupled folding-binding cluster formation processes. In contrast to a recently
studied related proteinlike hydrophobic-polar heteropolymer model, aggregation
and crystallization are separate processes for a homopolymer with the same
small bending rigidity. Rather stiff semiflexible polymers form a
liquid-crystal-like phase, as expected. In analogy to the heteropolymer study,
we find that the first-order-like aggregation transition of the complexes is
accompanied by strong system-size dependent hierarchical surface effects. In
consequence, the polymer aggregation is a phase-separation process with entropy
reduction.Comment: 5 pages, 3 figures, 1 tabl
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
Qualidade de frutos de abacaxi pérola em função do tamanho e estådio de maturação na colheita.
Nos Ășltimos tempos consumidores tem sido mais rigorosos nas suas exigĂȘncias quanto aos padrĂ”es de qualidade dos alimentos, principalmente para consumo in natura, tendo em vista que as caracterĂsticas e a aparĂȘncia do produto sĂŁo fatores determinantes na comercialização (Bengozi et al., 2007)
Experimental study of fragmentation products in the reactions 112Sn + 112Sn and 124Sn + 124Sn at 1 AGeV
Production cross-sections and longitudinal velocity distributions of the
projectile-like residues produced in the reactions 112Sn + 112Sn and 124Sn +
124Sn both at an incident beam energy of 1 AGeV were measured with the
high-resolution magnetic spectrometer, the Fragment Separator (FRS) of GSI. For
both reactions the characteristics of the velocity distributions and nuclide
production cross sections were determined for residues with atomic number Z
10. A comparison of the results of the two reactions is presented.Comment: 14 pages, 12 figure
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