We present novel understandings of the Gamma-Poisson (GaP) model, a probabilistic matrix factorization model for count data. We show that GaP can be rewritten free of the score/activation matrix. This gives us new insights about the estimation of the topic/dictionary matrix by maximum marginal likelihood estimation. In particular, this explains the robustness of this estimator to over-specified...

Purpose: Scientific data on wear from toothbrushing of luting cements for fixed partial dentures (FPDs) are limited and inconsistent, therefore the study aimed: (1) to investigate the effect of marginal gap width on cement wear and (2) to compare the resistance to wear from toothbrushing of five luting materials in an in vitro model. Materials and Methods: one zinc phosphate cement (ZPC), glass...

this paper using generalized roeger's model calculated the lerner index for iranian active industries in 4-digit isic codes during the period 1995-2007. the findings indicate that the lerner index has been between 8 to 16 percent in 38 industries among 131 ones. the index also in different industries shows that more than 50 percent of iranian industries have monopolistic power such that th...

OBJECTIVES The purpose of this study was to evaluate the Vickers hardness number (VHN) and the in vitro marginal adaptation of inlay restorations of three hybrid composite resins (Filtek Z250, Opallis and Esthet-X) subjected to two post-cure treatments. MATERIAL AND METHODS For the microhardness test, three different groups were prepared in accordance with the post-cure treatments: control gr...

OBJECTIVES Secondary caries is the most common reason for composite restoration replacement and usually forms between dentin and the filling. The objective of this study was to investigate the combined effect of cyclic loading and bacterial exposure on bacterial penetration into gaps at the interface between dentin and resin composite restorative material using a novel bioreactor system and tes...

OBJECTIVES To evaluate microleakage and marginal gaps in full cast crown restorations bonded with six different types of cementing agents. METHODS Sixty non-carious human premolars and molars were prepared in a standardized manner for full cast crown restorations. The mesial and distal margins were located in dentin, while the vestibular and palatal/lingual margins were located in enamel. Cro...

Sufficient cause interactions concern cases in which there is a particular causal mechanism for some outcome that requires the presence of 2 or more specific causes to operate. Empirical conditions have been derived to test for sufficient cause interactions. However, when regression outcome models are used to control for confounding variables in tests for sufficient cause interactions, the outc...