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Rasch Analysis of the Daily Living Tasks Dependent on Vision (DLTV)

Publication Date
  • Purpose
  • To Examine Internal Consistency
  • Refine The Response Scale
  • And Obtain A Linear Scoring System For The Visual Function Instrument
  • The Daily Living Tasks Dependent On Vision (Dltv)
  • Methods
  • Data Were Available From 186 Participants With A Clinical Diagnosis Of Amd Who Completed The 22-Item
  • An Independent Group Of 386 Participants With Amd Were Administered A Reduced Version Of The Dltv Wi
  • According To A Five-Point Response Scale
  • Rasch Analysis Was Performed On Both Datasets And Used To Generate Item Statistics For Measure Order
  • Response Odds Ratios Per Item And Per Person
  • And Infit And Outfit Mean Square Statistics
  • The Rasch Output From The Dltv-22 Was Examined To Identify Redundant Items And For Factorial Validit
  • Results
  • The Average Rating For The Dltv-22 Changed Monotonically With The Magnitude Of The Latent Person Tra
  • The Expected Versus Observed Average Measures Were Extremely Close
  • With Step Calibrations Evenly Separated For The Four-Point Ordinal Scale
  • In The Case Of The Dltv-11
  • Step Calibrations Were Not As Evenly Separated
  • Suggesting That The Five-Point Scale Should Be Reduced To Either A Four- Or Three-Point Scale
  • Five Items In The Dltv-22 Were Removed
  • And All 17 Remaining Items Had Good Infit And Outfit Mean Squares
  • Pca With Residuals From Rasch Analysis Identified Two Domains Containing 7 And 10 Items Each
  • The Domains Had High Person Separation Reliabilities (0
  • 86 And 0
  • 77 For Domains 1 And 2
  • Respectively) And Item Measure Reliabilities (0
  • 99 And 0
  • 98 For Domains 1 And 2
  • Respectively)
  • Conclusions
  • With The Improved Internal Consistency
  • Establishment Of The Accuracy And Precision Of The Rating Scale For The Dltv And The Establishment O
  • Biology
  • Medicine


1 Ludwig Eichinger and Francisco Rivero (eds.), Dictyostelium discoideum Protocols, Methods in Molecular Biology 983, DOI 10.1007/978-1-62703-302-2_1, © Springer Science+Business Media, LLC 2013 Chapter 1 The Amoebozoa Christina Schilde and Pauline Schaap Abstract The model organism Dictyostelium discoideum is a member of the Amoebozoa, one of the six major divisions of eukaryotes. Amoebozoa comprise a wide variety of amoeboid and fl agellate organisms with single cells measuring from 5 μ m to several meters across. They have adopted many different life styles and sexual behaviors and can live in all but the most extreme environments. This chapter provides an overview of Amoebozoan diversity and compares roads towards multicellularity within the Amoebozoa with inven- tions of multicellularity in other protist divisions. The chapter closes with a scenario for the evolution of Dictyostelid multicellularity from an Amoebozoan stress response. Key words Amoebozoa , Protista , Aggregative multicellularity , Encystation , Sporulation , Morphogenesis , Cyclic AMP signaling , Phylogeny The Dictyostelids have fascinated biologists for over 150 years with their ability to assemble up to a million amoebas into a tactile migrating organism, which, after seeking out a site for spore dis- persal, transforms into a well-balanced fruiting structure. The development of a range of molecular genetic and cell biological procedures for the species Dictyostelium discoideum over the past 30 years has established this species as an important model organ- ism for the study of fundamental cell biological and developmental processes ( 1 ) . More recently, the evolution of social behavior and the study of genes associated with human diseases and bacterial infections have been added to the repertoire of research questions that can be addressed in Dictyostelia ( 2 ) . With putative applications of research in mind,

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