Poor housing and stroke mortality in population over 64 years old at the parish level,in mainland Portugal

Housing conditions can impact physical and mental health. In 2013, Portugal was still the fourth European Union country with the highest percentage of population without an adequately heated home in winter. Other adverse conditions are, for instance, overcrowding and living in older buildings. Some studies stress the relationship between stroke and poor living conditions in the elderly population, especially cold homes. Univariate and multivariate spatial cluster analysis were used to explore the relationship between excess stroke death risk, from 1998 to 2004, measured by the standardized mortality ratio (SMR) for several cohorts (including persons over 64 years old), and poor housing variables from the 2001 census, at the parish level in continental Portugal. A multivariate cluster of parishes, with population without any form of heating their homes as dominant condition, was detected in northwest Portugal. Mean and median SMR values across all cohorts were consistently higher within this cluster. This strengthens the hypothesis that cold homes deserve more attention in stroke prevention and mitigation amongst elderly persons, especially in northwestern continental Portugal.     

Redox and nonredox reactions of magnetite and hematite in rocks

Redox and nonredox reactions causing pseudomorphic replacement of hematite by magnetite and magnetite by hematite are compared.Pseudomorphic replacements resulting from redox reactions are known as martitization [replacement of magnetite by hematite due to oxidation; reaction (1)] and mushketovitization [replacement of hematite by magnetite due to reduction; reaction (2)]. These two replacements cause characteristic ore textures and volume changes (reaction (1): increase of 1.66%; reaction (2): decrease of 1.64%). These small volume changes are the reason that martitization and mushketovitization are widespread in many rocks under condition, however, that oxidizing or reducing fluids (solutions) are present.The same initial and end products may also be involved in nonredox reactions. Reaction (3) is the replacement of hematite by magnetite due to simple addition of Fe²⁺ atoms under basic conditions. This reaction causes an increase of the volume of 47.6%. Reaction (4), causing a volume decrease of 32.2%, is the replacement of magnetite by hematite due to leaching of Fe²⁺ atoms under acidic conditions. From these volume changes it is concluded that reaction (4) may occur in many rock types, whereas reaction (3) is restricted to unlithified sediments only. However, ore textures caused by nonredox reactions are unknown and therefore their occurrence in rocks is hypothetical.