In this short paper we prove that the classic simplex method with the mostnegative-reduced-cost pivoting rule (Dantzig 1947) for solving the Markov decision problem (MDP) with a fixed discount rate is a strongly polynomial-time algorithm. The result seems surprising since this very pivoting rule was shown to be exponential for solving a general linear programming (LP) problem, and the simplex (...

Performance of the Xpert MTB/RIF assay, designed to simultaneously detect Mycobacterium tuberculosis complex (MTBC) and rifampin (RIF) resistance, has been well documented in low-resource settings with high TB-incidence. However, few studies have assessed its accuracy in low TB incidence settings. We evaluated the performance of Xpert MTB/RIF using clinical sputum specimens routinely collected ...

Rosette inhibitory factor, RIF, previously described in serum from patients with hepatitis B virus infection, has been isolated and identified as a minor species of beta-lipoprotein of the low-density (LDL) class. It is unrelated to hepatitis B virus proteins or particles. Although discrete by reference to charge and density (1.050 +/- 0.004 g/cm3), RIF appears to be a complex macromolecular st...

Abstract Recurrent implantation failure (RIF) is an imprecisely defined disorder lacking a robust scientific basis. The incomplete understanding of RIF provides significant diagnostic and therapeutic challenges, better the underlying issues necessary to improve outcomes. We propose novel concept termed ‘Theoretical Cumulative Implantation Rate’, calculation which based on objective data, define...

Complex symmetric systems do not in general admit a Cholesky factorization without pivoting, as would be the case for hermitian systems. Nevertheless, for some complex symmetric systems, as those coming from the discretization of boundary integral formulations, pivoting can be avoided. We present a Cholesky factorization algorithm for such complex symmetric systems. We propose a LAPACK-style im...

The Xpert MTB/RIF assay (Xpert) is a rapid test for tuberculosis (TB) and rifampin resistance (RIF-R) suitable for point-of-care testing. However, it has decreased sensitivity in smear-negative sputum, and false identification of RIF-R occasionally occurs. We developed the Xpert MTB/RIF Ultra assay (Ultra) to improve performance. Ultra and Xpert limits of detection (LOD), dynamic ranges, and RI...

Almost block diagonal linear systems of equations can be exemplified by two modules. This makes it possible to construct all sequential forms of band and/or block elimination methods, six old and fourteen new. It allows easy assessment of the methods on the basis of their operation counts, storage needs, and admissibility of partial pivoting. It unveils a robust partial pivoting strategylocal p...

Rifampicin (RIF) is a major component in fixed dose combination therapy for the treatment of tuberculosis. RIF has low solubility and high permeability with high dose and hence it is classified as class II drug in Biopharmaceutical Classification System (BCS). RIF has poor and variable bioavailability because of its poor solubility, acid decomposition and, drug and food interaction. The present...

Our objective was to assess the cost-benefit of enhancing or replacing the conventional sputum smear with the real-time PCR Xpert MTB/RIF method in the inpatient diagnostic schema for tuberculosis (TB).Recent data from published per-case cost studies for TB/multidrug-resistant (MDR)-TB and from comparative analyses of sputum microscopy, mycobacterial culture, Xpert MTB/RIF and drug susceptibili...

We read the recent paper by Rufai et al. with interest (1). The authors tested a subset of samples containing Mycobacterium tuberculosis previously tested by the Hain line probe assay (LPA) with the Xpert MTB/RIF assay to identify discordant results between these two test methods. The authors’ results favored LPA over Xpert MTB/RIF in sensitivity for rifampin (RIF) resistance detection. These r...