Measurement of the half-life of 198Au in a non-metal: High-precision measurement shows no host-material dependence

We have measured the half-life of the beta decay of 198Au to be 2.6948(9) d, with the nuclide sited in an insulating environment. Comparing this result with the half-life we measured previously with a metallic environment, we find the half-lives in both environments to be the same within 0.04%, thus contradicting a prediction that screening from a "plasma" of quasi-free electrons in a metal increases the half-life by as much as 7%

Cajal, Retzius, and Cajal–Retzius cells

The marginal zone (MZ) of the prenatal cerebral cortex plays a crucial role in cellular migration and laminar patterning in the developing neocortex and its equivalent in the adult brain - layer I, participates in cortical circuitry integration within the adult neocortex. The MZ/layer I, which has also been called the plexiform layer and cell-poor zone of Meynert, among others, is home to several cell populations including glia, neurons and Cajal-Retzius (CR) cells. Cajal once said that the MZ is one of the oldest formations in the phylogenetic series, and that the characteristics of layer I in human are similar in all vertebrates except fish (Ramon y Cajal, 1899). Despite the presence of CR cells in the MZ/layer I of all developing and adult vertebrate brains, and more than one hundred years of research, the phenotype and function of layer I cells have still not been clearly defined. Recent technological advances have yielded significant progress in functional and developmental studies, but much remains to be understood about neurons in MZ/layer I. Since the time of Retzius and Cajal, and continuing with modern era research from the likes of Marín-Padilla, the study of CR cells has been based on their morphological characteristics in Golgi staining. However, since Cajal’s initial description, the term ‘CR cell’ has been applied differently and now is often used to indicate reelin (Reln) positive cells in MZ/layer I. Here we review the history of work by Cajal, Retzius and others pertaining to CR cells. We will establish a link between original descriptions of CR cell morphology by Cajal, Retzius and others, and current understandings of the cell populations that reside in MZ/layer I based on the use of cellular markers. We propose to use the term ‘CR cell’ for the class of neurons that express Reln in the MZ/layer I in both prenatal, developing and adult cerebral cortex

Cerebral aspergillosis simulating pyogenic abscesses

Background: A 29-year-young male patient with a history of HIV for approximately 4 years ago was admitted to the department of Internal Medicine for fever, with a headache resistant to analgesics. He also presented nausea without vomiting, and the fever persisted despite antibiotic treatment. CT scan was carried out, followed by MRI in order to better characterize the lesions

Branching ratios for the beta decay of 21Na

We have measured the beta-decay branching ratio for the transition from 21Na to the first excited state of 21Ne. A recently published test of the standard model, which was based on a measurement of the beta-nu correlation in the decay of 21Na, depended on this branching ratio. However, until now only relatively imprecise (and, in some cases, contradictory) values existed for it. Our new result, 4.74(4)%, reduces but does not remove the reported discrepancy with the standard model.Comment: Revtex4, 2 fig

Experimental Validation of the Largest Calculated Isospin-Symmetry-Breaking Effect in a Superallowed Fermi Decay

A precision measurement of the gamma yields following the beta decay of 32Cl has determined its isobaric analogue branch to be (22.47^{+0.21}_{-0.19})%. Since it is an almost pure Fermi decay, we can also determine the amount of isospin-symmetry breaking in this superallowed transition. We find a very large value, delta_C=5.3(9)%, in agreement with a shell-model calculation. This result sets a benchmark for isospin-symmetry-breaking calculations and lends support for similarly-calculated, yet smaller, corrections that are currently applied to 0+ -> 0+ transitions for tests of the Standard Model