This contribution brings to a close a special issue of Hydrology and Earth System Sciences concerning the assessment of nitrogen dynamics in catchments across Europe within a semi-distributed Integrated Nitrogen model for multiple source assessment in Catchments (INCA). The wide range of issues involved in relation to hydrology and within-catchment processes, scale (from small catchments to maj...

The letter written by Heinze (1) has serious shortcomings. Heinze wrote that There is not a single study of healthy men from any fertility center or sperm bank that has reported a decline in sperm counts in the United States. This is not true. A number of such studies exist. Leto and Frensilli (2) documented a decline in sperm counts in potential sperm donors from all over the United States in ...

The authors fail to control for relevant "third" variables that could easily explain the weak correlations that they find. Family violence exposure for instance, peer group influences, certainly genetic influences on aggressive behavior are just a few relevant variables that ought either be controlled or at minimum acknowledged as alternate causal agents for (very small) link between video game...

Cigarette smoking is the largest preventable cause of death and disability in developed countries and is a rapidly growing health problem in developing countries. The magnitude and nature of the risks associated with smoking can be estimated using data from prospective epidemiological studies of smokers and nonsmokers and information on smoking in the population. In 1966 the National Cancer Ins...