BackgroundObservational studies have reported an inverse relationship between selenium status (blood or toenail) and the risk of laryngeal cancer; however, the impact of low serum selenium level on survival has not been evaluated.MethodsWe conducted a prospective study of 296 patients diagnosed with laryngeal cancer in Szczecin, Poland. Serum selenium was measured at diagnosis and prior to treatment. Patients were followed from the date of diagnosis to death at five years. Vital status was obtained by linkage to the Polish National Death Registry.ResultsThe five-year survival after diagnosis was 82.0% (95% CI: 68% to 91%) for individuals in the highest quartile of serum selenium (> 66.8 μg/L) and was 28.6% (95% CI 19% to 42%) for individuals in the lowest quartile (<50.0 μg/L). In an age- and sex-adjusted analysis, the hazard ratio (HR) for death from all causes was 7.01 (95% CI 3.81 to 12.9) for patients in the lowest quartile of serum selenium, compared to those in the highest quartile. The corresponding multivariate HR was 3.07 (95% CI 1.59 to 5.94).ConclusionsThis study suggests that a selenium level in excess of 70 μg/L is associated with improved outcome among patients undergoing treatment for laryngeal cancer. Further studies are needed to evaluate if selenium supplementation to achieve this level might improve overall prognosis.

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Application of Kernel Estimation in Analysis of Labour Productivity of the Largest Polish Firms in 2004-2008The parametric methods of statistical and econometric analysis are not always useful in examination of labour productivity of economic entities. In previous works the Authors found that the labour productivity is characterized by the lack of stable regularities in the range of structure and interdependency. In that case it is possible to apply non-parametric methods. In the paper the Authors tried to model the distributions of the labour productivity in time by means of kernel estimation using classical approaches (Epanechnikov, Rosenblatt) and the new proposition called kernel B. It seems that proposed approach is a useful merger of the statistical modeling theory and economic practice which allows to analyze the changes in the labour productivity - the essential factor for long-term economic growth and the welfare of society. The empirical results show that the labour productivity in the largest Polish companies had increased in 2004-2008 but the growths had not the same dynamics in different economic sectors.

Introduction. The obstetricians attitudes towards caesarean delivery at the threshold of viability were explored in a European project (EUROBS) in eight countries: France, Germany, Italy, Luxembourg, Netherlands, Spain, Sweden and the UK.Methods. In each country, NICU-associated obstetrical units were selected through census or random sampling. An anonymous self-administered questionnaire explored the obstetricians attitudes regarding the lowest gestational age at which they would perform a caesarean delivery in case of acute foetal distress of a single, non-malformed and normally grown fetus given that: a) parents want everything possible done to save the baby; b) parents favour non-aggressive management for fear of disability; and c) the obstetrician him/herself is one of the parents. Data collection took place in [2001][2002]; 105 units and 1530 obstetricians participated (response rates 70% and 77% respectively).Results. At 24 weeks of gestational age, 71% of the German, 52% of the Swedish, and 27% of the Italian and British obstetricians would perform a caesarean delivery given parental agreement, compared with only 17% of the French, 14% of the Spanish, and less than 1% of the Dutch ones. The intervention would be postponed by an average of 3.8 days (95% CI 2.9 -4.7) in case of parental opposition to active management, and by 5.7 days (95% CI 4.1-7.3) if the obstetrician was one of the parents. Other factors significantly associated with a more advanced caesarean section threshold in a multivariate model were older age, being a woman, muslim and oriental religion, more pessimistic beliefs regarding neonatal prognosis, and consultation with neonatologist.Conclusions. The lowest gestational age at which obstetricians would perform a caesarean delivery for fetal indication only varies according to country, parental views, and personal physician characteristics and beliefs. These findings have implications for neonatologists subsequent actions, and for the international comparison of perinatal statistics.

The main source of data on the labour market are sets of the official statistics. The aim of the article is to analyze the availability of the data used in forecasting: supply and demand of labour by occupation, the number of graduates by occupation, variables related to unemployment, as well as diagnosing demand for qualifications and skills at the local and regional labour markets. The analysis was conducted on the example of a system devised for the Zachodniopomorskie voivodship. A system of monitoring indicators was built for this very province.