[Like a Stone in Well]

HIV prevalence in Zimbabwe dropping like a stone.

HIV in Zimbabwe is disappearing like ‘snow in the desert’, in dramatic contrast to its neighbouring countries, mystifying epidemiologists, one of whom firmly believes the anomaly can be attributed to the country’s relatively high level of education. Brian Williams of the South African Centre for Epidemiological Modelling and Analysis (SACEMA), was speaking at the 2nd Consortium to Respond Effec...

Letters to the editor: like a rolling stone?

Mechanical Properties and Structures of Oil-well Cement Stone Reinforced with Siliceous Whisker

To fully utilize the siliceous whiskers and improve the mechanical properties of oil-well cement, the cement composites with different additions of siliceous whiskers were prepared, and analyzed by means of scanning electron microscopy (SEM), mechanical testing, X-ray diffraction (XRD), and infrared spectrum analysis. The results showed that the addition of 2% siliceous whiskers could slightly ...

Stone Composition in Patients Who Undergo Renal Stone Surgery: Review of 423 Stone Analyses in Southern Iran

Well-poised Generation of Apéry-like Recursions

where the fixed (but not necessarily real) parameter α satisfies the condition Reα < 1. Substituting α = 0 into the resulting recurrence equations produces the famous recursions for ζ(2) = 2Z 2 (0), ζ(3) = Z3(0) due to Apéry [Ap], as well as the recursion for ζ(4) = Z4(0) known as the Cohen–Rhin–Sorokin–Zudilin recursion ([Co], [So], [Zu1]) that is honest from both historical and alphabetical p...