Capablanca's stroke: an early case of neurogenic heart disease. Cuban-world-champion of chess 1921-1927

The great chess master Jose Raul Capablanca died of a stroke in New York city in 1942. An analysis of his death is instructive in the discussion of cardiac repercussions of hypertensive cerebral hemorrhage, particularly regarding the close relationship between subendocardial hemorrhage and its probable source - sympathetic activation - caused by stroke.     

DEEPLY COLOURED AND BLACK GLASS IN THE NORTHERN PROVINCES OF THE ROMAN EMPIRE: DIFFERENCES AND SIMILARITIES IN CHEMICAL COMPOSITION BEFORE AND AFTER ad 150*

In this work we attempt to elucidate the chronological and geographical origin of deeply coloured and black glass dating between 100 bc and ad 300 on the basis of their major and trace element compositions. Samples from the western and eastern parts of the Roman Empire were analysed. Analytical data were obtained by means of a scanning electron microscope – energy‐dispersive system (SEM–EDS, 63 samples analysed) and laser ablation – inductively coupled plasma – mass spectrometry (LA–ICP–MS, 41 samples analysed). Among the glass fragments analysed, dark brown, dark purple and dark green hues could be distinguished. Only among the dark green fragments could a clear compositional distinction be observed between fragments dated to the periods before and after ad 150. In the early samples (first century bc to first century ad ), iron, responsible for the green hue, was introduced by using impure sand containing relatively high amounts of Ti. In contrast, a Ti‐poor source of iron was employed, containing Sb, Co and Pb in trace quantities, in order to obtain the dark green colour in the later glass samples. The analytical results obtained by combining SEM–EDS and LA–ICP–MS are therefore consistent with a differentiation of glassmaking recipes, detectable in glass composition, occurring in the period around ad 150.     

EPR OF Mn2+ IMPURITIES IN CALCITE: A DETAILED STUDY PERTINENT TO MARBLE PROVENANCE DETERMINATION*

We demonstrate that the electron paramagnetic resonance spectrum of Mn²⁺ impurities in calcite, and therefore also in marble, may be accurately reproduced by a traditional spin Hamiltonian formalism. The success of such a treatment, however, very much depends on the spin Hamiltonian parameters having the correct signs as well as magnitudes. We present data that determine the sign of the axial anisotropy parameter and thereby facilitate future quantum mechanical characterizations of marble electron paramagnetic resonance spectra that supplement provenance determination.     

Chemical characterization of some potsherd pavements from parts of Yorubaland in southwestern Nigeria

Several samples of potsherd pavement were recovered during excavation and archaeological reconnaissance of six sites, along the trade and migration route of the Yoruba of southwestern Nigeria. A significant feature of these pavements is the similarity to Ife in design which consists of a herringbone design, with a ritual pot embedded in their middle. Microscopic analysis of samples shows the presence of high proportions of non-plastic grains, mainly quartz, micas, minor plagioclases, and traces of ferruginous grains, tourmaline and amphibole, interpreted as being produced by low temperature firing. Major, trace and rare earth elements' composition of 21 samples of sherds was determined using Inductively Coupled Plasma (ICP-MS) technique. The chemistry of the potsherd samples is generally similar to regolith derived from granitic rocks, which are abundant in the area. Principal component analysis (PCA) was used to reduce the number of variables and model-based cluster analysis was used to find clusters in the PCA scores. Model-based clustering found one major cluster in the data set, which corresponds to the local weathered granitic/pegmatitic raw materials near the sites. Our work shows that the technology for the manufacture of these pavements might have originated from Ile-Ife, but the production was geologically controlled.