Ross filter

Ross filter method, 108, 109 Rowland grating, concave, 121 Rubidium, determination by x-ray emission spectrography, 328 Ruthenium, determination by x-ray emission spectrography, 328... 

Fig. 7-29 Ross filters for Cu Ka radiation (a) absorption coefficients of filter materials . (b) values after balancing.

In environmental analyses, Ross and Sievers [629] analysed water and solid particles trapped on air sampling filters and for the detection of beryllium chelates used on ECD... 

As described by Sedwick et al. (this issue), a semicontinuous culture of the Ross Sea P. antarctica strain was successively diluted with low-iron (<0.2 nM dissolved Fe) filtered Ross Sea seawater, over a period of several weeks, using a rigorous trace-metal-clean protocol. Using this process, we obtained an inoculum culture of colonial P. antarctica in LI medium diluted 9,140-fold with filtered, low-iron (0.17 nM dissolved Fe) Ross Sea seawater, for which we calculate dissolved Fe and EDTA concentrations of 1.42 nM and 1.25 nM, respectively. Prior to commencing... 

Bacterial production was estimated by incorporation of 3H-thymidine (Fuhrman and Azam 1982). Duplicate 10 ml subsamples were incubated for 1 h in the dark at 2°C in the presence of 20 nM of 3H-thymidine (Amersham 40-50 Ci mol ), filtered on 0.2-pm cellulose acetate membrane filters (Sarto-rius) and extracted with ice-cold 5% Trichloroacetic acid (TCA) (Becquevort and Smith 2001). Thymidine incorporation was converted into bacterial production using conversion factors of Ducklow et al. (1999) established for the Ross Sea bacterial communities (i.e., 8.6 X 1017 bacteria produced per mole of thymidine incorporated in the cold TCA insoluble material). For bacterial production, the relative standard deviation was 9.3% (n = 20). The specific growth rate was estimated from bacterial production and bacterial biomass. 

Air samples were taken at Ross Island, Cape Evans, and processed by filtering through polyurethane foam plugs connected in series (76). After extraction with an acetone-hexane mixture, determinations of 24 PCB congeners, p,p -DDT, p,p -DDE and lindane were accomplished by capillary GC with EC detection. Geochemical means (in pg m ) were 15.2, 2.0, 1.0 and 25.8 for the above compounds in the given order. Lindane concentrations were found to correlate well with seasonal variations (higher levels in summer and autumn), whereas the other chlorinated hydrocarbons showed no dependence on seasons. 

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