Myxococcus xanthus dsp and dif mutants have similar phenotypes in that they are deficient in social motility and fruiting body development. We compared the two loci by genetic mapping, complementation with a cosmid clone, DNA sequencing, and gene disruption and found that 16 of the 18 dsp alleles map to the dif genes. Another dsp allele contains a mutation in the sglK gene. About 36.6 kb around...

Evaluating measurement equivalence (also known as differential item functioning (DIF)) is an important part of the process of validating psychometric questionnaires. This study aimed at evaluating the multiple indicators multiple causes (MIMIC) model for DIF detection when latent construct distribution is nonnormal and the focal group sample size is small. In this simulation-based study, Type I...

BACKGROUND Short scales are typically used in the social, behavioural and health sciences. This is relevant since test length can influence whether items showing DIF are correctly flagged. This paper compares the relative effectiveness of discriminant logistic regression (DLR) and IRTLRDIF for detecting DIF in polytomous short tests. METHOD A simulation study was designed. Test length, sample...

In this paper, two integrated Bayesian models for differential item functioning (DIF) analysis in item response theory (IRT) models are proposed and compared. The model is integrated in the sense of modelling the responses along with the DIF determination, thus allowing DIF detection and DIF explanation in a simultaneous setup. DIF occurs because item characteristics may change according to gro...

Differential item functioning (DIF) is when a test item favors or hinders a characteristic exhibited by group members of a test-taking population. DIF analyses are statistical procedures used to determine to what extent the content of an item affects the item endorsement of sub-groups of test-takers. If DIF is found for many items on the test, the final test scores do not represent the same mea...

Investigating the existence of items with differential item functioning (DIF) may provide more accurate comparisons group differences in studies that aim to compare scores obtained a test by groups different characteristics. In present study, scale measuring critical thinking motivation was adapted Turkish culture applied 817 participants, who were high school graduates, university students, an...

Homologous recombination between the circular chromosomes of bacteria can generate chromosome dimers. They are resolved by a recombination event at a specific site in the replication terminus of chromosomes, dif, by dedicated tyrosine recombinases. The reaction is under the control of a cell division protein, FtsK, which assembles into active DNA pumps at mid-cell during septum formation. Previ...

Abstract In latent scaling applications, such as the positioning of political parties, differential item functioning (DIF) may occur because measurement issues or substantive differences in association between and manifest variables. While first source DIF has received considerable attention, second not, although it is potential interest to comparative scholars. this research note, we introduce...