A common misperception within the neural network community is that even with nonlinearities in their hidden layer, autoassociators trained with backpropagation are equivalent to linear methods such as principal component analysis (PCA). Our purpose is to demonstrate that nonlinear autoassociators actually behave differently from linear methods and that they can outperform these methods when use...

purpose: to determine the long-term visual outcomes and complications of penetrating keratoplasty (pk) performed for keratoconus. methods: hospital records of patients with keratoconus who underwent pk at the ophthalmology center of shaheed sadoughi, yazd, iran, during 1992-2003 were reviewed. we studied records of 84 pk procedures in 72 keratoconus patients. data including best corrected visua...

purpose : to assess the visual and refractive outcomes after implantation of toric implantable collamer lens (t-icl) in compound myopic astigmatism methods : in this prospective study, 28 eyes with manifest refraction spherical equivalent (mrse) errors of -10.94±4.09 diopter (d) and mean cylindrical errors of -3.47±1.39 d underwent t-icl implantation. six months after surgery, best corrected an...

An efficient, simple and convenient route is described for the synthesis of biscoumarin (3,3'-(arylmethylene) bis (4-hydroxy-2H-chromen-2-one)) by using of recyclable catalyst TiO2@KSF. In this Method, we synthesis biscoumarin derivatives via 3multi-component reactions (3MCRs) of two equivalent 4-hydroxycoumarin with one equivalent of aromatic aldehydes using 20 mg nano TiO2@KSF as homogeneous ...