5,539 research outputs found

    Search for low lying dipole strength in the neutron rich nucleus 26^{26}Ne

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    Coulomb excitation of the exotic neutron-rich nucleus 26^{26}Ne on a nat^{nat}Pb target was measured at 58 A.MeV in order to search for low-lying E1 strength above the neutron emission threshold. Data were also taken on an nat^{nat}Al target to estimate the nuclear contribution. The radioactive beam was produced by fragmentation of a 95 A.MeV 40^{40}Ar beam delivered by the RIKEN Research Facility. The set-up included a NaI gamma-ray array, a charged fragment hodoscope and a neutron wall. Using the invariant mass method in the 25^{25}Ne+n channel, we observe a sizable amount of E1 strength between 6 and 10 MeV. The reconstructed 26^{26}Ne angular distribution confirms its E1 nature. A reduced dipole transition probability of B(E1)=0.49±\pm0.16 e2fm2e^2fm^2 is deduced. For the first time, the decay pattern of low-lying strength in a neutron-rich nucleus is obtained. The results are discussed in terms of a pygmy resonance centered around 9 MeV

    Explanation of the Gibbs paradox within the framework of quantum thermodynamics

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    The issue of the Gibbs paradox is that when considering mixing of two gases within classical thermodynamics, the entropy of mixing appears to be a discontinuous function of the difference between the gases: it is finite for whatever small difference, but vanishes for identical gases. The resolution offered in the literature, with help of quantum mixing entropy, was later shown to be unsatisfactory precisely where it sought to resolve the paradox. Macroscopic thermodynamics, classical or quantum, is unsuitable for explaining the paradox, since it does not deal explicitly with the difference between the gases. The proper approach employs quantum thermodynamics, which deals with finite quantum systems coupled to a large bath and a macroscopic work source. Within quantum thermodynamics, entropy generally looses its dominant place and the target of the paradox is naturally shifted to the decrease of the maximally available work before and after mixing (mixing ergotropy). In contrast to entropy this is an unambiguous quantity. For almost identical gases the mixing ergotropy continuously goes to zero, thus resolving the paradox. In this approach the concept of ``difference between the gases'' gets a clear operational meaning related to the possibilities of controlling the involved quantum states. Difficulties which prevent resolutions of the paradox in its entropic formulation do not arise here. The mixing ergotropy has several counter-intuitive features. It can increase when less precise operations are allowed. In the quantum situation (in contrast to the classical one) the mixing ergotropy can also increase when decreasing the degree of mixing between the gases, or when decreasing their distinguishability. These points go against a direct association of physical irreversibility with lack of information.Comment: Published version. New title. 17 pages Revte

    Accelerator and Reactor Neutrino Oscillation Experiments in a Simple Three-Generation Framework

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    We present a new approach to the analysis of neutrino oscillation experiments, in the one mass-scale limit of the three-generation scheme. In this framework we reanalyze and recombine the most constraining accelerator and reactor data, in order to draw precise bounds in the new parameter space. We consider our graphical representations as particularly suited to show the interplay among the different oscillation channels. Within the same framework, the discovery potential of future short and long baseline experiments is also investigated, in the light of both the recent signal from the LSND experiment and the atmospheric neutrino anomaly.Comment: uuencoded compressed tar file. Figures (13) available by ftp to ftp://eku.sns.ias.edu/pub/lisi/ (192.16.204.30). Submitted to Physical Review

    Incidence of reversible amenorrhea in women with breast cancer undergoing adjuvant anthracycline-based chemotherapy with or without docetaxel

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    <p>Abstract</p> <p>Background</p> <p>To determine the incidence of reversible amenorrhea in women with breast cancer undergoing adjuvant anthracycline-based chemotherapy with or without docetaxel.</p> <p>Methods</p> <p>We studied the incidence and duration of amenorrhea induced by two chemotherapy regimens: (i) 6 cycles of 5-fluorouracil 500 mg/m<sup>2</sup>, epirubicin 100 mg/m<sup>2 </sup>and cyclophosphamide 500 mg/m<sup>2 </sup>on day 1 every 3 weeks (6FEC) and (ii) 3 cycles of FEC 100 followed by 3 cycles of docetaxel 100 mg/m<sup>2 </sup>on day 1 every 3 weeks (3FEC/3D). Reversible amenorrhea was defined as recovery of regular menses and, where available (101 patients), premenopausal hormone values (luteinizing hormone (LH), follicle-stimulating hormone (FSH) and estradiol) in the year following the end of chemotherapy.</p> <p>Results</p> <p>One hundred and fifty-four premenopausal patients were included: 84 treated with 6FEC and 70 with 3FEC/3D. The median age was 43.5 years (range: 28–58) in the 6FEC arm and 44 years (range: 29–53) in the 3FEC/3D arm. Seventy-eight percent of patients were treated in the context of the PACS 01 trial. The incidence of chemotherapy-induced amenorrhea at the end of chemotherapy was similar in the two groups: 93 % in the 6FEC arm and 92.8 % in the 3FEC/3D arm. However, in the year following the end of chemotherapy, more patients recovered menses in the 3FEC/3D arm than in the 6FEC arm: 35.5 % versus 23.7 % (p = 0.019). Among the 101 patients for whom hormone values were available, 43 % in the 3FEC/3D arm and 29 % in the 6FEC arm showed premenopausal levels one year after the end of chemotherapy (p < 0.01). In the 3FEC/3D group, there was a statistically significant advantage in disease-free survival (DFS) for patients who were still amenorrheic after one year, compared to patients who had recovered regular menses (p = 0.0017).</p> <p>Conclusion</p> <p>Our study suggests that 3FEC/3D treatment induces more reversible amenorrhea than 6FEC. The clinical relevance of these findings needs to be investigated further.</p

    LH prevents cisplatin-induced apoptosis in oocytes and preserves female fertility in mouse

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    Premature ovarian failure and female infertility are frequent side effects of anticancer therapies, owing to the extreme sensitivity of the ovarian reserve oocytes to the damaging effects of irradiation and chemotherapy on DNA. We report here a robust protective effect of luteinizing hormone (LH) on the primordial follicle pool of prepubertal ovaries against the cisplatin (Cs)-induced apoptosis. In vitro LH treatment of prepubertal ovarian fragments generated anti-apoptotic signals by a subset of ovarian somatic cells expressing LH receptor (LHR) through cAMP/PKA and Akt pathways. Such signals, reducing the oocyte level of pro-apoptotic TAp63 protein and favoring the repair of the Cs-damaged DNA in the oocytes, prevented their apoptosis. Noteworthy, in vivo administration to prepubertal female mice of a single dose of LH together with Cs inhibited the depletion of the primordial follicle reserve caused by the drug and preserved their fertility in reproductive age, preventing significant alteration in the number of pregnancy and of delivered pups. In conclusion, these findings establish a novel ovoprotective role for LH and further support the very attracting prospective to use physiological 'fertoprotective' approaches for preventing premature infertility and risks linked to precocious menopause in young patients who survived cancer after chemotherapy

    Transport properties of heterogeneous materials derived from Gaussian random fields: Bounds and Simulation

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    We investigate the effective conductivity (σe\sigma_e) of a class of amorphous media defined by the level-cut of a Gaussian random field. The three point solid-solid correlation function is derived and utilised in the evaluation of the Beran-Milton bounds. Simulations are used to calculate σe\sigma_e for a variety of fields and volume fractions at several different conductivity contrasts. Relatively large differences in σe\sigma_e are observed between the Gaussian media and the identical overlapping sphere model used previously as a `model' amorphous medium. In contrast σe\sigma_e shows little variability between different Gaussian media.Comment: 15 pages, 14 figure

    Reducing recurrent care proceedings: initial evidence from new interventions

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    The English family justice system faces a crisis of recurrence. As many as one in four birth mothers involved in public law care proceedings in English family courts are likely to reappear in a subsequent set of proceedings within seven years. These mothers are involved in up to one-third of total care applications, as they are – by definition – linked to more than one child . Few birth mothers experiencing the removal of a child to care are offered any follow-up support, despite often facing multiple challenges including poverty, addiction, domestic violence and mental health problems. Since 2011, however, a number of new services have been established to begin to address their unmet needs. This article summarises the findings of the first academic-led evaluation of two of these initiatives. Presenting evidence from a mixed-methods evaluative study, it concludes that the new services were able to foster relationships that ‘worked’ in reducing recurrent proceedings. None of the women engaging with the services went on to experience what could be described as a ‘rapid repeat pregnancy’ within the evaluation window. Just as significantly, a number of clients reported some improvement in their psychological functioning, and the practitioners involved reported positively on their experience of delivering and managing innovative services. The article closes with a discussion of the challenges of evaluating personalised, strengths-based interventions and the possibilities of evidencing empowerment in these cases

    Structure of the N=27 isotones derived from the 44^{44}Ar(d,p)45^{45}Ar

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    Expérience GANIL/SPIRAL, détecteur CATS, détecteur MUST, 7 figures,International audienceThe 44^{44}Ar(d,p)45^{45}Ar neutron transfer reaction was performed at 10~A.MeV. Measured excitation energies, deduced angular momenta and spectroscopic factors of the states populated in 45^{45}Ar are reported. A satisfactory description of these properties is achieved in the shell model framework using a new sdpfsdpf interaction. The model analysis is extended to more exotic even-Z nuclei down to 1441^{41}_{14}Si27_{27} to study how collectivity impacts the low lying structure of N~=~27 neutron-rich nuclei

    Decay Pattern of Pygmy States Observed in Neutron-Rich 26 Ne

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    Coulomb excitation of the exotic neutron-rich nucleus Ne26 on a Pb208 target was measured at 58 MeV/u in order to search for low-lying E1 strength above the neutron emission threshold. This radioactive beam experiment was carried out at the RIKEN Accelerator Research Facility. Using the invariant mass method in the Ne25+n channel, we observe a sizable amount of E1 strength between 6 and 10 MeV excitation energy. By performing a multipole decomposition of the differential cross section, a reduced dipole transition probability of B(E1)=0.49+-0.16e2fm2 is deduced, corresponding to 4.9+-1.6% of the Thomas-Reiche-Kuhn sum rule. For the first time, the decay pattern of low-lying strength in a neutron-rich nucleus is measured. The extracted decay pattern is not consistent with several mean-field theory descriptions of the pygmy states.Comment: arXiv admin note: text overlap with arXiv:0705.175
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