Unfortunately, all of these practices have limitations; for instance, multiple sample preparation steps and longer chromatography using shallow gradients decrease sample throughput without actually eliminating problems related to matrix effect.
In order to improve the accuracy of air quality forecasting, there are usually three approaches to deal with missing data before modeling: (1) deleting sample instances with missing data; (2) replacing missing values; and (3) using multiple imputations.
In several instances, multiple samples were obtained over the 2-year period, resulting in 23 total water well samples (8 samples of dissolved gas, 15 samples of free gas) and 1 salt spring sample (free gas) analyzed at Isotech Laboratories in 2009 and 2010.
The ROC curves were also created by using a bootstrap methodology, which creates multiple samples (1,000) by randomly drawing instances, with replacement, from the original study population [ 36].
For instance, TAC levels in multiple samples of apple juice were compared to individual antioxidant levels separately analyzed by HPLC (Karaman et al. 2010).
We introduced the entity SampleCollection as an aggregate of Sample to decouple the mapping from Sample to Data and handle data instances that merge information coming from multiple samples (see Figure 2).
In most instances, sampling for nonpersistent chemicals, whether environmental or biological, will require multiple samples taken over the course of the study at regular intervals (e.g., weekly, monthly, semiannually, etc).
There were 26 instances of high intra-specific divergence (>3%) among the 338 species with multiple samples (Table 2).
Distinctly narrow rings seen in multiple samples are of particular interest because they indicate that a single factor limiting the growth of the trees — a drought, for instance — was in existence across the site.
Distinctly narrow rings seen in multiple samples are of particular interest because they indicate that a single factor limiting the growth of the trees a drought, for instance was in existence across the site.
With this assay, multiple samples can be handled in parallel.
