Recent data set

Figure 8. ° Pb7 Pb vs. Th/Us (derived using Eqn. 5 in the text) diagram for mid-ocean ridge and ocean island basalt based on a recent data set with mostly mass spectrometry measurements (Turner et al. 1997 Bourdon et al. 1996 Dosso et al. 1999 Claude-lvanaj et al. 1998, 2001 Sims et al. 2002). The data show a relatively well defined array that intersect a closed-system hne for the bulk Earth starting with an initial lead isotope composition equal to Canyon Diablo (T = 4.55 Ga). This intersect was used by Allegre et al. (1986) to define the Th/U ratio of the Earth.

An indication of what one might eventually expect to obtain for a generalized pattern of relative bio-availability for the actinides of interest in nuclear fuel cycles is shown in Table IV. This represents a recent data set in which concentration ratios have been obtained for all five actinides in tissues of a vertebrate (used as human food) from a single aquatic ecosystem (Pond 3513 at ORNL) comparisons are thus facilitated. The values for bone (Table IV) suggest a pattern of bio-availability as follows ... 

Most recent data sets are accompanied by either estimates of errors of the measurements or observed sample-to-sample fluctuations which were entered into the library, as modern CMB programs (e.g., 13) use uncertainties of the source compositions and in ambient samples in weighted least-squares fitting procedures. Many older data sets do not include estimates of analytical errors or fluctuations of particle composition, so we attached estimates based on the... 

GDP growth rate. The projected growth rate was slightly higher than recent predictions, so in this step the projections were downgraded for consistency with the recent data set. The adjustment, however, was relatively small (minus 0.28 Mt). 

Yip and Marlin showed that RTO performance can be improved through the use of multiple data sets for updating.f In this approach, a moving window of fixed size is used to keep a record of the current and most recent data sets for updating. Using multiple data sets increases the parameter observability and reduces the variability of the parameter estimates. 

Recently, several QSPR solubility prediction models based on a fairly large and diverse data set were generated. Huuskonen developed the models using MLRA and back-propagation neural networks (BPG) on a data set of 1297 diverse compoimds [22]. The compounds were described by 24 atom-type E-state indices and six other topological indices. For the 413 compoimds in the test set, MLRA gave = 0.88 and s = 0.71 and neural network provided... 

More recently, attempts have been made to correlate mathematically the chemical composition of natural waters and their aggressivity to iron by direct measurements on corrosion coupons or pipe samples removed from distribution systemsThis work has been of limited success, either producing a mathematical best fit only for the particular data set examined or very general trends. The particular interest to the water supply industry of the corrosivity of natural waters to cast iron has led to the development of a simple corrosion rig for the direct measurement of corrosion ratesThe results obtained using this rig has suggested an aggressivity classification of waters by source type i.e. 

A globally based measurement network for atmospheric Hg does not exist. Longterm measurements of TGHg have, however, been performed at some land-based stations. Data from remote marine sites are mainly available from research cruises. Recently, Slemr et al. (2003) compiled TGHg data from a number of permanent stations and oceanic cruises for the northern and southern hemispheres (Figure 2.7). Although the data set is incomplete, a peak in TGHg concentrations seems to have... 

Bignert A, Riget F, Braune B, Outridge P, Wilson S. 2004. Recent temporal trend monitoring of mercury in Arctic biota — how powerful are the existing data sets J Environ Monitoring 6 351-355. 

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