Most previous studies involve observations at a single time point, or cross sectional designs, and longitudinal evidence of the developmental trajectories of particular difficulties is limited.
This single report about categorical variable difficulties (Picone et al., 2007) was classified as partially established, because further investigations are required to determine whether the difficulty is limited to graphs or whether students also struggle with the concept of categorical variables in general.
The inclusion of images within printed examination papers is now technically possible, but data regarding their effect on psychometric item properties, such as difficulty and discrimination, are limited [ 19, 45].
Heavy-transport helicopters, such as the Mil Mi-26 or Sikorsky S-64 Skycrane, address some of these difficulties, but their payloads are limited to 20 and nine tonnes respectively, and their huge rotors create a powerful downdraft that makes handling that payload rather tricky.
However, the study and application of III-V semiconanocrystalscrystare are limited by difficulties in their synthesis.
However, the applications are limited by difficulties encountered during the separation and regeneration processes.
Current techniques are limited by difficulties in contextualizing sequencing data with environmental metadata from the target ecosystem [ 46].
However, the empirical studies that report reasoning impairments more than appreciation impairments are limited by difficulties in the operationalizing of MacCAT-T appreciation (see below).
On the other hand, such approaches are limited by difficulties to determine the overall tumor cell load (that is, the number of tumor cells within a potentially mixed infiltrate or nodule) as well as the distant spread of tumor cells.
Although studies to identify gene expression signatures in DCIS are limited by difficulties in obtaining frozen material from DCIS, we were able to collect a relatively large series of DCIS cases for this purpose.
