Emission of the greenhouse gases nitrous oxide and methane from constructed wetlands in europe.

The potential atmospheric impact of constructed wetlands (CWs) should be examined as there is a worldwide increase in the development of these systems. Fluxes of N(2)O, CH(4), and CO(2) have been measured from CWs in Estonia, Finland, Norway, and Poland during winter and summer in horizontal and vertical subsurface flow (HSSF and VSSF), free surface water (FSW), and overland and groundwater flow (OGF) wetlands. The fluxes of N(2)O-N, CH(4)-C, and CO(2)-C ranged from -2.1 to 1000, -32 to 38 000, and -840 to 93 000 mg m(-2) d(-1), respectively. Emissions of N(2)O and CH(4) were significantly higher during summer than during winter. The VSSF wetlands had the highest fluxes of N(2)O during both summer and winter. Methane emissions were highest from the FSW wetlands during wintertime. In the HSSF wetlands, the emissions of N(2)O and CH(4) were in general highest in the inlet section. The vegetated ponds in the FSW wetlands released more N(2)O than the nonvegetated ponds. The global warming potential (GWP), summarizing the mean N(2)O and CH(4) emissions, ranged from 5700 to 26000 and 830 to 5100 mg CO(2) equivalents m(-2) d(-1) for the four CW types in summer and winter, respectively. The wintertime GWP was 8.5 to 89.5% of the corresponding summertime GWP, which highlights the importance of the cold season in the annual greenhouse gas release from north temperate and boreal CWs. However, due to their generally small area North European CWs were suggested to represent only a minor source for atmospheric N(2)O and CH(4).

Neuropsychological consequences of very low birth weight and asphyxia at term: follow-up until school-age.

This prospective, longitudinal study examined neuropsychological consequences of different conditions associated with risks of perinatal asphyxia. Four groups of children, 5 to 9 years of age, were studied: (1) very low birth weight (VLBW) children born small for gestational age (SGA) (n = 34); (2) VLBW children born appropriate for gestational age (AGA) (n = 43); (3) children with signs of birth asphyxia at term (birth asphyxia) (n = 36), and (4) control children (n = 45). Moderately and severely disabled children were excluded. The WISC-R and the NEPSY, a new neuropsychological assessment consisting of attention, language, motor, sensory, visuospatial, and memory subtests, were administered. The VLBW-SGA group had the poorest test results. The VLBW-AGA group was somewhat less impaired, whereas the birth asphyxia group performed at the control group level. Impairment, when present, tended to be diffuse in all groups, affecting psychometric intelligence, naming, visuo-motor performance, tactile finger discrimination, attention, and phonological analysis.