Spin-parity combinations in 16N from the 18O(d,α)16N reaction

The reaction ¹⁸O(d, α)¹⁶N has been studied using a tensor-polarized deuteron beam at incident energies of 8.50, 9.25, 10.00, 10.30, 10.75 and 11.30 MeV. From measurement of the tensor analysing power of the reaction when the α-particles are emitted near 0°, spin-parity combinations have been deduced for thirteen levels in ¹⁶N up to 6.2 MeV excitation. These results, together with previous work, lead to new and unambiguous spin and parity assignments for four of these levels.     

Functional MRI and multivariate autoregressive models

Connectivity refers to the relationships that exist between different regions of the brain. In the context of functional magnetic resonance imaging (fMRI), it implies a quantifiable relationship between hemodynamic signals from different regions. One aspect of this relationship is the existence of small timing differences in the signals in different regions. Delays of 100 ms or less may be measured with fMRI, and these may reflect important aspects of the manner in which brain circuits respond as well as the overall functional organization of the brain. The multivariate autoregressive time series model has features to recommend it for measuring these delays and is straightforward to apply to hemodynamic data. In this review, we describe the current usage of the multivariate autoregressive model for fMRI, discuss the issues that arise when it is applied to hemodynamic time series and consider several extensions. Connectivity measures like Granger causality that are based on the autoregressive model do not always reflect true neuronal connectivity; however, we conclude that careful experimental design could make this methodology quite useful in extending the information obtainable using fMRI.     

Applying the cluster method to count occurrences of generalized permutation patterns

We apply ideas from the cluster method to q-count the permutations of a multiset according to the number of occurrences of certain generalized patterns, as defined by Babson and Steingrímsson. In particular, we consider those patterns with three letters and one internal dash, as well as permutation statistics composed of counting the number of occurrences of multisets of such patterns. Counting is done via recurrences which simplify in the case of permutations. A collection of Maple procedures implementing these recurrences accompanies the article.     

Abundant stable gauge field hair for black holes in anti-de Sitter space

We present new hairy black hole solutions of SU(N) Einstein-Yang-Mills (EYM) theory in asymptotically anti-de Sitter (AdS) space. These black holes are described by N+1 independent parameters and have N-1 independent gauge field degrees of freedom. Solutions in which all gauge field functions have no zeros exist for all N, and for a sufficiently large (and negative) cosmological constant. At least some of these solutions are shown to be stable under classical, linear, spherically symmetric perturbations. Therefore there is no upper bound on the amount of stable gauge field hair with which a black hole in AdS can be endowed.     

Über die Bestimmung der Oxalsäure

Analytical and Bioanalytical Chemistry -     

Raney-Co mediated reductive cyclization of an alpha,beta-unsaturated nitrile

An expedient, five step synthesis of caprolactam 1 is reported starting from natural L-homoserine. The key step is a chemoselective reductive cyclization of alpha,beta-unsaturated nitrile 10 mediated by Raney-Co type metals. This hydrogenation is extensively investigated in order to account for the observed product distribution and yields.