29 research outputs found

    Quasiprojectile breakup and isospin equilibration at Fermi energies: an indication of longer projectile-target contact times?

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    An investigation of the quasiprojectile breakup channel in semiperipheral and peripheral collisions of 58,64^{58,64}Ni+58,64^{58,64}Ni at 32 and 52 MeV/nucleon is presented. Data have been acquired in the first experimental campaign of the INDRA-FAZIA apparatus in GANIL. The effect of isospin diffusion between projectile and target in the two asymmetric reactions has been highlighted by means of the isospin transport ratio technique, exploiting the neutron-to-proton ratio of the quasiprojectile reconstructed from the two breakup fragments. We found evidence that, for the same reaction centrality, a higher degree of relaxation of the initial isospin imbalance is achieved in the breakup channel with respect to the more populated binary output, possibly indicating the indirect selection of specific dynamical features. We have proposed an interpretation based on different average projectile-target contact times related to the two exit channels under investigation, with a longer interaction for the breakup channel. The time information has been extracted from AMD simulations of the studied systems coupled to GEMINI++: the model calculations support the hypothesis hereby presented

    Experimental study of isospin transport with 40,48^{40,48}Ca+ 40,48^{40,48}Ca reactions at 35 MeV/nucleon

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    International audienceWe investigate the isospin transport with 40,48 Ca+ 40,48 Ca reactions at 35 MeV/nucleon, measured with the coupling of the VAMOS high acceptance spectrometer and the INDRA charged particle multidetector. Using the quasi-projectile remnant measured with VAMOS and carefully selected light-charged-particles measured in coincidence with INDRA, a reconstruction method is applied to estimate the excited quasi-projectile (QP) on an event-by-event basis. The isospin diffusion is investigated using the isospin transport ratio with the asymmetry ÎŽ = (N − Z)/A of the projectile as an isospin-sensitive observable and the total transverse energy of Z ≀ 2 nuclei for experimental centrality sorting. The experimental isospin transport ratios present, for both the reconstructed QP and its remnant, a clear evolution towards isospin equilibration with increasing dissipation of the collision while the full equilibration is not reached. A smoother evolution with less discrepancies between the two mixed systems in the case of the reconstructed QP is also observed. The isospin migration is investigated using the neutron-to-proton ratio of the light-charged-clusters and the velocity of the QP remnant as a sorting parameter. More particularly, we focused on an angular region centered around the mid-rapidity of the reaction so as to characterize the low-density neck emissions. A systematic neutron-enrichment is observed and interpreted as a consequence of isospin migration, more particularly for the symmetric systems which present no isospin gradient between the projectile and the target. We also noticed that the ^{2}H and ^{4}He particles exhibit very close multiplicities independently of the sorting variable for the symmetric systems

    Experimental study of isospin transport with 40,48^{40,48}Ca+ 40,48^{40,48}Ca reactions at 35 MeV/nucleon

    No full text
    International audienceWe investigate the isospin transport with 40,48 Ca+ 40,48 Ca reactions at 35 MeV/nucleon, measured with the coupling of the VAMOS high acceptance spectrometer and the INDRA charged particle multidetector. Using the quasi-projectile remnant measured with VAMOS and carefully selected light-charged-particles measured in coincidence with INDRA, a reconstruction method is applied to estimate the excited quasi-projectile (QP) on an event-by-event basis. The isospin diffusion is investigated using the isospin transport ratio with the asymmetry ÎŽ = (N − Z)/A of the projectile as an isospin-sensitive observable and the total transverse energy of Z ≀ 2 nuclei for experimental centrality sorting. The experimental isospin transport ratios present, for both the reconstructed QP and its remnant, a clear evolution towards isospin equilibration with increasing dissipation of the collision while the full equilibration is not reached. A smoother evolution with less discrepancies between the two mixed systems in the case of the reconstructed QP is also observed. The isospin migration is investigated using the neutron-to-proton ratio of the light-charged-clusters and the velocity of the QP remnant as a sorting parameter. More particularly, we focused on an angular region centered around the mid-rapidity of the reaction so as to characterize the low-density neck emissions. A systematic neutron-enrichment is observed and interpreted as a consequence of isospin migration, more particularly for the symmetric systems which present no isospin gradient between the projectile and the target. We also noticed that the ^{2}H and ^{4}He particles exhibit very close multiplicities independently of the sorting variable for the symmetric systems

    [CCAFU Recommendations 2013: Prostate cancer].

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    International audienceIntroduction: The sub Comittee prostate of the CCAFU established guidelines for diagnostic, treatment, evaluation and standart of care of prostate cancer.Methods: Guidelines 2010 were updated based on systematic literature search performed by the sub-Comittee in Medline and PubMed databases to evaluate references, levels of evidence and grade of recommandation.Results: Pathological examination of the tissue specimens was defined specifically for Gleason score according to ISP 2005 recommandations. Prostate and pelvis RMN became the reference in terms of radiological exam. Individual and early diagnosis of prostate cancer was defined and role of PSA was precised. Active surveillance became one of the standart of care of low-risk tumors, radical prostatectomy remained one of the options for all risk group tumors, length of hormonotherapy in association with radiotherapy was precised according to the risk group. Side effects of hormonotherapy treament needed specific supervision ; hormonotherapy had no indication in case of non metastatic tumors and intermittent hormonotherapy in metastatic tumors. New hormonal drugs in pre and post chemotherapy and bone target drugs opened new therapeutics pathways.Conclusion: From 2010 to 2013, standarts of care of prostate cancer were modified because of results of prospective studies and new therapeutics. They allowed precise treatments for each specific clinical situation. In the future, multidisciplinary treatments for high risk tumors, time of adjuvant treatment and sequencies of new hormonal treatment had to be defined
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