The efficient solution of the normal equations corresponding to a large sparse linear least squares problem can be extremely challenging. Robust incomplete factorization (RIF) preconditioners represent one approach that has the important feature of computing an incomplete LLT factorization of the normal equations matrix without having to form the normal matrix itself. The right-looking implemen...

Rook pivoting is a relatively new pivoting strategy used in Gaussian elimination (GE). It can be as computationally cheap as partial pivoting and as stable as complete pivoting. This paper shows some new attractive features of rook pivoting. We first derive error bounds for the LU factors computed by GE and show rook pivoting usually gives a highly accurate U factor. Then we show accuracy of th...

This paper deals with the amount of disorder that is left in a permutation after one of its elements has been selected with quickselect with or without median-of-three pivoting. Five measures of disorder are considered: inversions, cycles of length less than or equal to some m, cycles of any length, expected cycle length, and the distance to the identity permutation. “Grand averages” for each m...

Information retrieval can cause forgetting for related but non-retrieved information. Such retrieval-induced forgetting (RIF) has been previously found for semantically and episodically related information. The current study used RIF to examine whether response effector and location are encoded explicitly in action memory. Participants learned unique touchscreen responses to ten novel objects. ...

background: repeated implantation failure (rif) is defined as pregnancy failure after two to six times with at least ten high grade embryo transfer to uterus. a variety of causes have been anticipated for rif, including anatomical, autoimmune, genetics, endocrine and thrombotic anomalies. factors responsible for rif have important implication regarding treatment however in many couples a perfec...

Background: RIF is the most common cause of unsuccessful pregnancy after IVF. Among the various causes of RIF, the role of maternal genetic factors is of great significance. PAI-1 polymorphism is one of the notable polymorphisms in this field. In this study, the relationship between this polymorphism and the recurrent spontaneous abortions and infertility in different populations has been inves...

Background: Repeated implantation failure (RIF) is the main problem after using assisted reproductive techniques (ART). The main causes of RIF as a multifactorial problem including decrease in endometrial receptivity, defects of embryo or combinational. Successful embryo implantation depends on trophoblast proliferation, migration and invasion to the endometrium, all of which are associated wit...