A branch-point approximant for the equation of state of hard spheres

Using the first seven known virial coefficients and forcing it to possess two branch-point singularities, a new equation of state for the hard-sphere fluid is proposed. This equation of state predicts accurate values of the higher virial coefficients, a radius of convergence smaller than the close-packing value, and it is as accurate as the rescaled virial expansion and better than the Pad\'e [3/3] equations of state. Consequences regarding the convergence properties of the virial series and the use of similar equations of state for hard-core fluids in $d$ dimensions are also pointed out.Comment: 6 pages, 4 tables, 3 figures; v2: enlarged version, extension to other dimensionalities; v3: typos in references correcte

Patient education and disease activity: A study among rheumatoid arthritis patients

Objective: To determine whether patients experiencing high disease activity derive more benefit from patient education than those experiencing low disease activity. - \ud Methods: Data from a randomized study on the effects of a program of patient education were analyzed retrospectively. Four subgroups were studied: the high disease activity subgroup of patients who had participated in the educational program, the complementary low disease activity subgroup, the high disease activity subgroup of controls, and its low disease activity complement. Patients with erythrocyte sedimentation rate >28 mm/first hour were classified as having high disease activity. Effects on frequency of physical exercises, endurance exercises, and relaxation exercises and effects on health status (Modified Health Assessment Questionnaire, Dutch Arthritis Impact Measurement Scales [AIMS]) were measured. - \ud Results: There were no significant differences between the adherence parameters of the various pairs of groups. Four months after the educational program began, anxiety and depression scores on the Dutch-AIMS had increased among participating patients who were experiencing high disease activity and decreased among those who were experiencing low disease activity. - \ud Conclusions: Patients experiencing high disease activity did not derive more benefit from patient education than those experiencing low disease activity. On the contrary, an increase of anxiety and depression is found in these patients. Further study is needed to confirm our findings

Blind extraction algorithm with direct desired signal selection.

In many practical applications we are interested in the extraction of only one desired signal out of a mixture of signals. A disadvantage of most blind extraction approaches proposed in the literature is that they are inefficient in the sense that they also separate or extract undesired signals. To deal with this inefficiency we exploit an a priori guess of direction of arrival related parameters of the desired signal, which serves as a mold. Based on this mold we create linear combinations of noise-free correlation matrices that are used to construct a single matrix with a specific eigenstructure. The eigenvector that corresponds to the smallest eigenvalue of this matrix is the desired extraction filter. Finally it is shown that this approach paves the way to make the algorithm flexible in the utilization of additional a priori information