340 research outputs found
Approximate particle number projection for finite range density dependent forces
The Lipkin-Nogami method is generalized to deal with finite range density
dependent forces. New expressions are derived and realistic calculations with
the Gogny force are performed for the nuclei Er and Er. The
sharp phase transition predicted by the mean field approximation is washed out
by the Lipkin-Nogami approach; a much better agreement with the experimental
data is reached with the new approach than with the Hartree-Fock_Bogoliubov
one, specially at high spins.Comment: 5 pages, RevTeX 3.0, 3 postscript figures included using uufiles.
Submitted to Phys. Rev. Let
Emerging collectivity from the nuclear structure of Xe 132: Inelastic neutron scattering studies and shell-model calculations
Inelastic neutron scattering was used to study the low-lying nuclear structure of 132Xe. A comprehensive level scheme is presented, as well as new level lifetimes, multipole mixing ratios, branching ratios, and transition probabilities. Comparisons of these data as well as previously measured E2 strengths and g factors are made with new shell-model calculations for 132, 134, 136 Xe
to explore the emergence of collectivity in the Xe isotopes with N<82 near the closed shell.This material is based upon work supported by the US
National Science Foundation under Grant No. PHY-1606890.
This research was also sponsored in part by the Australian
Research Council under Grant No. DP17010167
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Single particle states in the heaviest known nuclei
Neutron single-particle states above the N=152 subshell have been studied by high-resolution (d,p) reaction on a {sup 250}Cf target. All of the orbitals between N=152 and N=164 subshells have been identified. A tentative assignment has been made for the 1/2-(750) Nilsson state. 10 refs
High-Precision Branching Ratio Measurement for the Superallowed + Emitter 74Rb
A high-precision branching-ratio measurement for the superallowed β
+ decay of 74Rb was performed at the
TRIUMF Isotope Separator and Accelerator (ISAC) radioactive ion-beam facility. The scintillating electronpositron
tagging array (SCEPTAR), composed of 10 thin plastic scintillators, was used to detect the emitted β
particles; the 8π spectrometer, an array of 20 Compton-suppressed HPGe detectors, was used for detecting γ rays
that were emitted following Gamow-Teller and nonanalog Fermi β
+ decays of 74Rb; and the Pentagonal Array
of Conversion Electron Spectrometers (PACES), an array of 5 Si(Li) detectors, was employed for measuring
β-delayed conversion electrons. Twenty-three excited states were identified in 74Kr following 8.241(4) × 108
detected 74Rb β decays. A total of 58 γ -ray and electron transitions were placed in the decay scheme, allowing
the superallowed branching ratio to be determined as B0 = 99.545(31)%. Combined with previous half-life and
Q-value measurements, the superallowed branching ratio measured in this work leads to a superallowed f t value
of 3082.8(65) s. Comparisons between this superallowed f t value and the world-average-corrected Ft value, as
well as the nonanalog Fermi branching ratios determined in this work, provide guidance for theoretical models
of the isospin-symmetry-breaking corrections in this mass region.IS
The origin of polyploids via 2n gametes in Vaccinium section Cyanococcus
The production of 2n pollen (pollen with the sporophytic chromosome number) was evaluated in 4x and 6x taxa of Vaccinium section Cyanococcus . Mean frequencies of 2n pollen producers were 17.1% and 8.3% in natural 4x and 6x populations, respectively. The frequency of 2n pollen producers in the 4x species ranged from 8.6% ( V. angustifolium ) to 23.8% ( V. pallidum ). Level of 2n pollen production was genotypically variable (1% to 37.4%). The widespread occurrence of 2n pollen in 2x, 4x and 6x taxa suggests that sexual polyploidization was widespread and responsible for the origin of the polyploid species found in this genus. The frequency of 2n pollen producers was not significantly different between the 4x species and their putative 2x ancestors. These results support the origin of 4x and 6x taxa as a consequence of sexual polyploidization. Polyploids derived from sexual polyploidization would be expected to have increased fitness and flexibility due to the mode of 2n pollen formation. In blueberry species the predominant mode of 2n pollen formation is genetically equivalent to a first division restitution mechanism (FDR). FDR 2n pollen transmits a high percentage of the heterozygosity and a large fraction of the epistasis from the 2x parent to the 4x offspring.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42736/1/10681_2004_Article_BF00039664.pd
Firm spin and parity assignments for high-lying, low-spin levels in stable Si isotopes
A natural silicon target was investigated in a natSi(γ, γ′) photon-scattering experiment with fully linearly-polarised, quasi-monochromatic γ rays in the entrance channel. The mean photon energies used were ⟨ Eγ⟩ = 9.33, 9.77, 10.17, 10.55, 10.93, and 11.37 MeV, and the relative energy spread (full width at half maximum) of the incident beam was ΔEγ/ ⟨ Eγ⟩ ≈ 3.5–4 %. The observed angular distributions for the ground-state decay allow firm spin and parity assignments for several levels of the stable even-even silicon isotopes
Relatório de estágio na Câmara Municipal de Ourém
O presente relatório enquadra-se no âmbito do trabalho final do curso Mestrado em Reabilitação Urbana, do Instituto Politécnico de Tomar.
O estágio decorreu na Câmara Municipal de Ourém e teve como objeto, participar na coordenação com a Divisão Obras Municipais, Divisão da Ação Cultural e Divisão de Educação e Assuntos Sociais em intervenções a nível da Reabilitação Urbana.
O estágio numa Câmara Municipal foi a opção que pareceu mais enriquecedora para conclusão do Mestrado em Reabilitação Urbana e para o futuro da minha vida profissional. Esta opção de estágio deve-se ao desejo de poder aplicar alguns dos conhecimentos obtidos ao longo do Mestrado, de conhecer a realidade do trabalho em obra e inserido numa equipa profissional, fiscalizadora, lidando com as responsabilidades inerentes à profissão.
O relatório aborda quatro casos de estudo, respeitante às reabilitações, 1ª fase de intervenção na capela de São Sebastião em Atouguia, 2ª fase da reabilitação de zona de lazer no Agroal, freguesia de Formigais, 1ª fase de intervenção da capela da Perucha e reforço do pontão de Caxarias. Acompanhamento de pequenas reabilitações, reclamadas por juntas de freguesia e munícipes.
O relatório procura descrever os procedimentos adotados no acompanhamento das obras de reabilitação e para fácil entendimento as descrições são acompanhadas por fotografias
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