Impact of economic conditions on the secondary sex ratio in a post-communist economy.

According to the Trivers-Willard hypothesis the secondary sex ratio (SSR, the ratio of male to female newborns [M/F]) should be positively related to the parents' living conditions. This also means that if in some population parents experience environmental (e.g. economic) stress, the SSR should be relatively low. If this holds true, the fluctuations in the SSR of offspring could be one of the ways the human population reacts to environmental (and also socio-economic) changes. Although confirmed for many human populations, such a relationship was not observed in the populations living in the communist-era planned-economy countries until recently. We test the hypothesis that economic stress in Poland after the communist era is also related to the SSR decrease. Using quarterly data from the years 1995-2007 about the total number of live male (M) and female (F) newborns born in central Poland (sample size=310,532), we calculated the time series of the SSR. The quarterly economic conditions of the studied population within the period under consideration constituted the time series of the percentage change in private consumption at constant prices of the year 2000. The relationship between the SSR and the economic conditions in the analyzed 47 quarters of the year was tested with the use of the ARMA models. We have found that four quarters (one year) after the occurrence of economic stress there was a decline in the SSR. This result is consistent with the Trivers-Willard hypothesis at the population level in a modern free-trade economy of a post-communist country.

[Juliusz August Roger (1819-1865) a physician, welfare worker, humanist, naturalist]. / Juliusz August Roger (1819-1865) lekarz, spolecznik, humanista i przyrodnik.

A biography of Juliusz Roger a physician, humanist and a naturalist is presented. Doctor Roger, who was of German origin, spent most of his life in Silesia where he become known as a physician, social activist and a German enthusiast of the Polish folklore in the area. In the 1863 he published The Songs and Music of the Polish People in Upper Silesia. He was also valued entomologist who wrote several works on beetles and ants. As a physician Roger helped to reorganize and extend hospitals at Rudy Wielkie and Pilchowice near Gliwice and he collected funds for construction of the municipal hospital in Rybnik that has been functioning to the present day.