PM2.5 assessment in 21 European study centers of ECRHS II: Method and first winter results

The follow-up of a cohort of adults from 29 European centers of the former European Community Respiratory Health Survey (ECRHS) I (1989-1992) will examine the long-term effects of exposure to ambient air pollution on the incidence, course, and prognosis of respiratory diseases, in particular asthma and decline in lung function. The purpose of this article is to describe the methodology and the European-wide quality control program for the collection of particles with 50% cut-off size of 2.5 microm aerodynamic diameter (PM2.5) in the ECRHS II and to present the PM2.5 results from the winter period 2000-2001. Because PM2.5 is not routinely monitored in Europe, we measured PM2.5 mass concentrations in 21 participating centers to estimate background exposure in these cities. A standardized protocol was developed using identical equipment in each center (U.S. Environmental Protection Agency Well Impactor Ninety-Six [WINS] and PQ167 from BGI, Inc.). Filters were weighed in a single central laboratory. Sampling was conducted for 7 days per month for a year. Winter mean PM2.5 mass concentrations (November 2000-February 2001) varied substantially, with Iceland reporting the lowest value (5 microg/m3) and northern Italy the highest (69 microg/m3). A standardized procedure appropriate for PM2.5 exposure assessment in a multicenter study was developed. We expect ECRHS II to have sufficient variation in exposure to assess long-term effects of air pollution in this cohort. Any bias caused by variation in the characteristics of the chosen monitoring location (e.g., proximity to traffic sources) will be addressed in later analyses. Given the homogenous spatial distribution of PM2.5, however, concentrations measured near traffic are not expected to differ substantially from those measured at urban background sites.     

Praxisnah an der Front der Forschung: Umweltwissenschaften interdisziplin?r bei ecomed

Ohne Zusammenfassung     

The pit-trapping foraging strategy of the ant lion,Myrmeleon immaculatus DeGeer (Neuroptera: Myrmeleontidae)

Summary Larvae of Myrmeleon immaculatus in large pits captured both large and samll prey, while larvae in small pits captured only the small prey. Larvae in small pits did not respond to large ants, although they always responded by sand-flinging to small ants. Larvae in medium-sized pits often captured large ants only after prolonged and vigorous sand-flipping. Larvae in large pits usually captured large ants with relatively little sand-flipping. Pit enlargement and pit relocation in the laboratory were not significantly correlated with reduction of rations in the first 3 weeks after a pit was built. However, after a month without food, larvae on the average moved once every 10 days, built successively smaller pits, and moved longer distances before building a new pit. In the field pits were dug primarily in response to microclimatological factors and possibly edge-effects. The presence or absence of suitable prey at a site, per se, had no effect on whether or not a larva would dig a pit there. We conclude that these sit-and-wait predators have a relatively large repertoire of behavior that enhances their foraging success, and we contrast it with previously made optimal foraging models relating to pit locations, pit relocations, pit size and ant lion responses.     

Neues von der Nervenzellmembran

Information processing in the brain requires the activation of electrically and chemically gated ion channels in the neuronal plasma membrane. Recently, the function and the molecular composition of some of these membrane proteins have become the subject of extensive biochemical and biophysical analysis. From the currently available data, it is proposed that the architecture of different neuronal ion channels obeys common structural principles which may have resulted from a divergent evolution of a limited number of ancestor transmembrane polypeptides.