Isospin and spin-isospin modes in charge-exchange reactions

The microscopic structure of the Gamow-Teller resonance (GTR) and spin-dipole resonance (SDR) in 208Bi has been investigated in the 208Pb(3He,tp)207Pb reaction at E(3He)=450 MeV and very forward scattering angles. The partial and total branching ratios and the escape widths for GTR and SDR decay to the residual neutron-hole states in 207Pb were deduced. These are found to be in good agreement with recent theoretical estimates. The (3He,tp) reaction on Pb at E(3He)=177 MeV was also studied in order to locate isovector monopole strength corresponding to 2ℏω transitions. Monopole strength at excitation energies above 25 MeV was discovered and compared to calculated strength due to the isovector giant monopole resonance and the spin-flip isovector monopole resonance. Calculations in a normal-mode framework show that all isovector monopole strength can be accounted for if the branching ratio for decay by proton emission is 20%

Distribuição espacial do sistema radicular do cafeeiro fertirrigado por gotejamento em Campinas Root distribution of fertirrigated coffee trees in Campinas, State of São Paulo, Brazil

Este estudo teve como objetivo avaliar o efeito da fertirrigação por gotejamento, utilizando-se emissores com diferentes espaçamentos (0,50 ou 0,80 m) e profundidades de instalação (superficial, 0,10 e 0,20 m), na distribuição espacial do sistema radicular do cafeeiro. Observaram-se no cafeeiro irrigado e adubado de forma convencional diferentes condições de desenvolvimento radicular, variando conforme os tratamentos impostos. Para as plantas irrigadas por tubogotejadores com emissores espaçados a cada 0,50 m, a profundidade radicular efetiva foi menor (média de 0,63 m) do que a observada para as plantas irrigadas por emissores posicionados a cada 0,80 m (média de 0,70 m). No manejo nutricional por fertirrigação observou-se menor desigualdade na profundidade radicular efetiva entre os tratamentos, bem como, em um aumento médio de 51,1% de densidade de raízes. Houve tendência de manutenção do volume radicular na região próxima aos emissores, enquanto nos pontos mais distantes do desenvolvimento do bulbo úmido, o crescimento radicular foi de 77%. A irrigação das plantas por tubogotejadores enterrados a 0,10 m de profundidade proporcionou maior desenvolvimento radicular em resposta à fertirrigação.<br>This study aimed to evaluate the effect of the drip fertirrigation system, by using emitters with different arranging of spaces (0.50 or 0.80 m) and depths of installation (superficial, 0.10 or 0.20 m on the ground), over the root spatial distribution of coffee tree. The coffee tree conventionally irrigated and fertilized presented different conditions of root development, varying according to the treatment imposed. For plants irrigated by emitters spaced every 0.50 m, the effective root depth was smaller (mean of 0.63 m) than that observed for plants irrigated by emitters spaced every 0.80 m (mean of 0.70 m). The fertirrigation nutritional management allowed an uniform effective root depth among the treatments, as well as an increase of 51.1% in root density. There was a trend of maintenance of root volume in the places closer to the emitters, while in the most distant points of development of wet bulb, the growth of roots reached 77%. The plants irrigated by 0.10 m depth emitters provided the largest root development in response to fertirrigation

Three fragment sequential decay of heavy nuclei around 3 MeV/u excitation energy

A new method is proposed to identify the sequential decay of hot nuclei into large fragments. This method is based on a minimization procedure. It is illustrated for the Ar+Au reaction at 30 MeV/u. In this case, corresponding to about 3 MeV/u excitation energy, it is shown that the three fragment production can be explained by sequential binary splittings.SCOPUS: ar.jinfo:eu-repo/semantics/publishe