80 research outputs found
Assessment of fissionable material behaviour in fission chambers
A comprehensive study is performed in order to assess the pertinence of fission chambers coated with different fissile materials for high neutron flux detection. Three neutron scenarios are proposed to study the fast component of a high neutron flux: (i) high neutron flux with a significant thermal contribution such as BR2, (ii) DEMO magnetic fusion reactor, and (iii) IFMIF high flux test module.
In this study, the inventory code ACAB is used to analyze the following questions: (i) impact of different deposits in fission chambers; (ii) effect of the irradiation time/burn-up on the concentration; (iii) impact of activation cross-section uncertainties on the composition of the deposit for all the range of burn-up/irradiation neutron fluences of interest. The complete set of nuclear data (decay, fission yield, activation cross-sections, and uncertainties) provided in the EAF2007 data library are used for this evaluation
New pathway to bypass the 15O waiting point
We propose the sequential reaction process
O(,)O as a new pathway to bypass of the
O waiting point. This exotic reaction is found to have a surprisingly
high cross section, approximately 10 times higher than the
O(,)O. These cross sections were calculated after
precise measurements of energies and widths of the proton-unbound F low
lying states, obtained using the H(O,p)O reaction. The large
cross section can be understood to arise from the more
efficient feeding of the low energy wing of the ground state resonance by the
gamma decay. The implications of the new reaction in novae explosions and X-ray
bursts are discussed.Comment: submitte
Probing Nuclear forces beyond the drip-line using the mirror nuclei N and F
Radioactive beams of O and O were used to populate the resonant
states 1/2, 5/2 and in the unbound F and F
nuclei respectively by means of proton elastic scattering reactions in inverse
kinematics. Based on their large proton spectroscopic factor values, the
resonant states in F can be viewed as a core of O plus a proton
in the 2s or 1d shell and a neutron in 1p. Experimental
energies were used to derive the strength of the 2s-1p and
1d-1p proton-neutron interactions. It is found that the former
changes by 40% compared with the mirror nucleus N, and the second by
10%. This apparent symmetry breaking of the nuclear force between mirror nuclei
finds explanation in the role of the large coupling to the continuum for the
states built on an proton configuration.Comment: 6 pages, 3 figures, 2 tables, accepted for publication as a regular
article in Physical Review
VOLVULUS DU SIGMOIDE ET POST-PARTUM
The sigmoid volvulus during pregnancy is very rare and difficult to diagnose. It is often responsible for the mortality of the parturient and of the fetus. We report a case of sigmoid volvulus with postnatal complications. A multiparous woman aged 45, was admitted with a bowel obstruction and generalized abdominal spasm at 3 days postpartum. A laparotomy examination revealed a dolichocolon complicated by a sigmoid volvulus undergoing necrosis, with the presence of some pseudomembranes. Sigmoidectomy with proximal colostomy was performed according to Hartmann, following which the restoration of continuity was secured within two months. Sigmoid volvulus complicating pregnancy is a rare occurrence with a reserved maternal-fetal prognosis, the diagnosis should be suspected with the appearance of persistent abdominal pain associated with an occlusive syndrome. Urgent surgical intervention is required to reduce as far as possible fetomaternal morbidity and mortality.Le volvulus du sigmoĂŻde au cours de la grossesse est trĂšs rare et difficile Ă diagnostiquer. Elle peut sâaccompagner dâune mortalitĂ© maternelle et fĆtale importante. Nous rapportons un cas de volvulus du sigmoĂŻde compliquant les suites de couches. Une multipare de 45 ans, s'est prĂ©sentĂ©e avec un syndrome occlusif et dĂ©fense abdominale gĂ©nĂ©ralisĂ©e Ă J3 du post-partum. Une laparotomie exploratrice a mis en Ă©vidence un dolichocĂŽlon compliquĂ© par un volvulus du sigmoĂŻde nĂ©crosĂ©, avec prĂ©sence de quelques fausses membranes. Une rĂ©section sigmoĂŻdienne avec colostomie proximale selon Hartmann a Ă©tĂ© pratiquĂ©e, le rĂ©tablissement de la continuitĂ© a Ă©tĂ© rĂ©alisĂ© deux mois plus tard. Le volvulus du sigmoĂŻde compliquant la grossesse est une entitĂ© rare avec un pronostic materno-fĆtal rĂ©servĂ©, le diagnostic doit ĂȘtre suspectĂ© devant une douleur abdominale persistante associĂ©e Ă un syndrome occlusif. Lâintervention chirurgicale sâimpose en urgence pour rĂ©duire, au maximum, la morbiditĂ© et la mortalitĂ© maternofoetale
Marriage âsharia styleâ: everyday practices of Islamic morality in England
The growing visibility of Islam in the public spaces of Western societies is often interpreted in the media as a sign of Muslim radicalisation. This article questions this postulate by examining the flourishing Muslim marriage industry in the UK. It argues that these âhalalâ services, increasingly popular among the young generation of British Muslims, reflect the semantic shifting of categories away from the repertoire of Islamic jurisprudence to cultural and identity labels visible in public space. Informed by long-term ethnographic fieldwork in the British field of Islamic law, this article examines a Muslim speed-dating event, which took place in central London in 2013. It investigates how Islamic morality is maintained and negotiated in everyday social interactions rather than cultivated via discipline and the pursuit of virtuous dispositions. Using Goffmanâs âframe analysisâ and his interpretation of the social as a space of âperformancesâ as well as recent anthropological reflections on âordinary ethicsâ (Lambek) and âeveryday Islamâ (Schielke, Osella and Soares), it examines the potential for such practices to define the contours of a new public culture where difference is celebrated as a form of distinction
Monitoring the referral system through benchmarking in rural Niger: an evaluation of the functional relation between health centres and the district hospital
BACKGROUND: The main objective of this study is to establish a benchmark for referral rates in rural Niger so as to allow interpretation of routine referral data to assess the performance of the referral system in Niger. METHODS: Strict and controlled application of existing clinical decision trees in a sample of rural health centres allowed the estimation of the corresponding need for and characteristics of curative referrals in rural Niger. Compliance of referral was monitored as well. Need was matched against actual referral in 11 rural districts. The referral patterns were registered so as to get an idea on the types of pathology referred. RESULTS: The referral rate benchmark was set at 2.5 % of patients consulting at the health centre for curative reasons. Niger's rural districts have a referral rate of less than half this benchmark. Acceptability of referrals is low for the population and is adding to the deficient referral system in Niger. Mortality because of under-referral is highest among young children. CONCLUSION: Referral patterns show that the present programme approach to deliver health care leaves a large amount of unmet need for which only comprehensive first and second line health services can provide a proper answer. On the other hand, the benchmark suggests that well functioning health centres can take care of the vast majority of problems patients present with
An above-barrier narrow resonance in F-15
Intense and purified radioactive beam of post-accelerated O-14 was used to study the low-lying states in the unbound F-15 nucleus. Exploiting resonant elastic scattering in inverse kinematics with a thick target, the second excited state, a resonance at E-R = 4.757(6)(10) MeV with a width of Gamma = 36(5)(14) keV was measured for the first time with high precision. The structure of this narrow above-barrier state in a nucleus located two neutrons beyond the proton drip line was investigated using the Gamow Shell Model in the coupled channel representation with a C-12 core and three valence protons. It is found that it is an almost pure wave function of two quasi-bound protons in the 2s(1/2) shell. (C) 2016 The Authors. Published by Elsevier B.V
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