The Additive Factors Model (AFM), a widely used model of student learning, estimates students’ prior knowledge, the difficulty of tutored skills, and the rates at which these skills are learned. In contrast to Bayesian Knowledge Tracing (BKT), another widely used model of student learning, AFM does not have parameters for the slipping rates of learned skills; i.e., it does not explicitly model ...

Membrane vesicles (AFM ) were isolated from cell-free ascites fluid of Moloney virus-induced lymphoma-bearing mice. Biochemical analysis has indicated that the AFM. fraction is highly enriched in the plasma membrane en zyme marker 5 -nucleotidase. Neither reduced nicotinamide adenine dinucleotide dehydrogenase nor succinic dehydrogenase could be detected in the AFM,, fractions, indicating their...

The polyquaternium 7 polymer is widely used in cosmetic formulations. Morphologic alterations in hair fibers were observed after the application of the polyquaternium 7 polymer, using SEM and AFM. Continuous applications of this product indicated that it accumulates on the fibers, improving the aspect of the hair surface. Quantitative analysis of the images obtained by AFM was undertaken. The...

Spectroscopic analysis and atomic force microscopy (AFM) phase imaging studies show self-assembly of phenosafranin (PSF) to multiwalled carbon nanotubes (MWNTs). The shift in absorption spectra is associated with charge transfer of valence electrons from PSF to electron accepting sites on the MWNTs. The Raman-active disorder modes are used to fingerprint PSF attachment to MWNTs via defect state...

The genus Lippia (Verbenaceae) comprise around 160 species spread out mainly in South and Central Americas with few African species, some of them with potential medicinal use. Brazil is one the most important centers of diversity with approximately 75% of the species described so far. Innumerous species are endemic and poorly studied especially at a cytological level. Here, chromosomal length, ...

Recruitment of non-planted mangrove species into Rhizophora mucronata, Sonneratia alba and Avicennia marina reforested stands (all of them 5 years old) was investigated to assess possibilities for natural colonization. Corresponding bare (denuded or open without mangroves) and natural (relatively undisturbed) sites were used as controls. Interstitial water salinity and temperature (measured at ...

Applications of state-of-the-art atomic force microscopy methods to the elucidation of the surface and near-surface structure of polymeric solids are described. Contact, tapping, force modulation, frictional force, and other modes of atomic force microscopy are described, and recent results are summarized. Conformational and chain order, crystalline order, polymer crystals, lamellar structures,...

Atomic force microscopy (AFM) has been applied in many biological investigations in the past 15 years. This review focuses on the application of AFM for quantitatively characterizing the structural and thermodynamic properties of protein-protein and protein-nucleic acid complexes. AFM can be used to determine the stoichiometries and association constants of multiprotein assemblies and to quanti...