Unified description of the coupled-channels and statistical Hauser-Feshbach nuclear reaction theories for low energy neutron incident reactions

We incorporate the coupled-channels optical model into the statistical Hauser-Feshbach nuclear reaction theory, where the scattering matrix is diagonalized by performing the Engelbrecht-Weidenm\"{u}ller transformation. This technique has been implemented in the coupled-channels optical model code ECIS by J. Raynal, and we extend this method so that all the open channels in a nucleon-induced reaction on a deformed nucleus can be calculated consistently

Absorption-Fluctuation Theorem for Nuclear Reactions: Brink-Axel, Incomplete Fusion and All That

We discuss the connection between absorption, averages and fluctuations in nuclear reactions. The fluctuations in the entrance channel result in the compound nucleus, Hauser-Feshbach, cross section, the fluctuations in the intermediate channels, result in modifications of multistep reaction cross sections, while the fluctuations in the final channel result in hybrid cross sections that can be used to describe incomplete fusion reactions. We discuss the latter in details and comment on the validity of the assumptions used in the develpoment of the Surrogate method. We also discuss the theory of multistep reactions with regards to intermediate state fluctuations and the energy dependence and non-locality of the intermediate channels optical potentials.Comment: 9 pages. Contribution to the International Workshop on Compound-Nuclear Reactions and Related Topics (CNR*2007), October 22-26, 2007, Fish Camp, California. To be published in AIP Proceedings (Editor Jutta Escher

A case of milk allergy that presented anaphylaxis after cutaneous contact with allergen

ABSTRACTMilk allergy in a 1-year and 8-month-old boy is reported. At 1 year and 1 month of age, the patient presented with anaphylaxis, including erythema, which was initially localized to the contact site of the anterior chest, and wheezing accompanied by dyspnea, 5 min after contact with milk allergen through his atopic skin. These symptoms continued for 50 min. Seventy minutes after the disappearance of the initial erythema, the patient developed subsequent erythematous lesions distributed throughout the neck and head area that persisted for as long as 24 h. On another occasion, he also exhibited a pale face and generalized erythema immediately after an accidental oral ingestion of milk at the age of 1 year and 8 months. He had been unsettled for several hours when an intravenous steroid was administered. His serum IgE was 590 IU/mL and the radioallergosorbent test (RAST) scores against milk, α-lactoalbumin, β-lactoglobulin, casein and cheese were 5, 2, 3, 5 and 5, respectively. This is a rare case of a patient with milk allergy who fell into anaphylaxis following both cutaneous contact with and oral ingestion of the offending milk protein. Care should be taken with patients with food allergies because cutaneous contact with the offending food may cause adverse reactions, including anaphylaxis

Neutron reactions in accreting neutron stars: a new pathway to efficient crust heating

In our calculation of neutron star crust heating we include several key new model features. In earlier work electron capture (EC) only allowed neutron emission from the daughter ground-state; here we calculate, in a deformed QRPA model, EC decay rates to all states in the daughter that are allowed by Gamow-Teller selection rules and energetics. The subsequent branching ratios between the 1n,...,xn channels and the competing $\gamma$-decay are calculated in a Hauser-Feshbach model. Since EC accesses excited states, many more neutrons are emitted in our calculation than in previous work, leading to accelerated reaction flows. In our multi-component plasma model a single (EC,xn) reaction step can produce several neutron-deficient nuclei, each of which can further decay by (EC,xn). Hence, the neutron emission occurs more continuously with increasing depth as compared to that in a one-component plasma model.Comment: Two color figures, accepted for publication by Physical Review Letter