Proposing a Hybrid Approach to Predict, Schedule and Select the Most Robust Project Portfolio under Uncertainty

Suitable project portfolio selection in inconsistent economy that can reduce the portfolio risks and increasing utilities for investors has gained significant research attentions.   This article addresses the project portfolio selection in which conventional certain (1) prediction, (2) optimization and (3) clustering approaches cannot be used to face uncertainty. To predict the real value of affecting project risk parameters, neural network has been used; Then to determine the optimized sequences and procedures, the proposed model have been evaluated using the multi-objective shuffle frog leaping algorithm (SFLA) by robust optimization approach; To suggest different risk criteria, K-means algorithm utilized to categorize the candidate projects and differentiating the clusters.  As the proposed hybrid methodology is studied on 420 different construction projects in an Iranian construction company in two economic stable years and an instable year in Iran real estate market. The results show 96 percent prediction-optimization capability due to different desired criteria

Double-strand break repair and homologous recombination in Schizosaccharomyces pombe

In recent years our understanding of double strand break repair and homologous recombination in Schizosaccharomyces pombe has increased significantly, and the identification of novel pathways and genes with homologues in higher eukaryotes has increased its value as a model organisms for double strand break repair. We will review the S. pombe literature on double strand break repair, mainly focussing on homologous recombination in mitotic cells

The CDK-Activating Kinase (CAK) Csk1 Is Required for Normal Levels of Homologous Recombination and Resistance to DNA Damage in Fission Yeast

BACKGROUND: Cyclin-dependent kinases (CDKs) perform essential roles in cell division and gene expression in all eukaryotes. The requirement for an upstream CDK-activating kinase (CAK) is also universally conserved, but the fission yeast Schizosaccharomyces pombe appears to be unique in having two CAKs with both overlapping and specialized functions that can be dissected genetically. The Mcs6 complex--orthologous to metazoan Cdk7/cyclin H/Mat1--activates the cell-cycle CDK, Cdk1, but its non-redundant essential function appears to be in regulation of gene expression, as part of transcription factor TFIIH. The other CAK is Csk1, an ortholog of budding yeast Cak1, which activates all three essential CDKs in S. pombe--Cdk1, Mcs6 and Cdk9, the catalytic subunit of positive transcription elongation factor b (P-TEFb)--but is not itself essential. METHODOLOGY/PRINCIPAL FINDINGS: Cells lacking csk1(+) are viable but hypersensitive to agents that damage DNA or block replication. Csk1 is required for normal levels of homologous recombination (HR), and interacts genetically with components of the HR pathway. Tests of damage sensitivity in csk1, mcs6 and cdk9 mutants indicate that Csk1 acts pleiotropically, through Cdk9 and at least one other target (but not through Mcs6) to preserve genomic integrity. CONCLUSIONS/SIGNIFICANCE: The two CAKs in fission yeast, which differ with respect to their substrate range and preferences for monomeric CDKs versus CDK/cyclin complexes as substrates, also support different functions of the CDK network in vivo. Csk1 plays a non-redundant role in safeguarding genomic integrity. We propose that specialized activation pathways dependent on different CAKs might insulate CDK functions important in DNA damage responses from those capable of triggering mitosis

An 8.2 kb DNA segment from chromosome XIV carries the RPD3 and PAS8 genes as well as the Saccharomyces cerevisiae homologue of the thiamine-repressed nmt1 gene and a chromosome III-duplicated gene for a putative aryl-alcohol dehydrogenase.

A 8.2 kb DNA segment from the left arm of Saccharomyces cerevisiae chromosome XIV (GenBank/EMBL accession number: X83226) encompasses four open reading frames (ORFs) longer than 100 residues. The ORF N0295 is highly similar to the Aspergillus parasiticus and Schizosaccharomyces pombe nmt1 gene products, which are involved in thiamine biosynthesis and are strongly repressed by thiamine. N0300 is 76% identical to YCR107w, a hypothetical protein of yeast chromosome III, and 55% identical to a ligninolytic aryl-alcohol dehydrogenase from the white-rot fungus Phanerochaete chrysosporium. In addition, this fragment encodes Rpd3, a pleiotropic transcription factor (Vidal and Gaber, 1991), and part of Pas8, a protein essential for the biogenesis of peroxisomes (Voorn-Brouwer et al., 1993)

New disruption cassettes for rapid gene disruption and marker rescue in the yeast Yarrowia lipolytica

Yarrowia lipolytica is one of the most extensively studied nonconventional yeasts. Unfortunately, few methods for gene disruption have been reported for this yeast, and all of them are time-consuming and laborious. The functional analysis of unknown genes requires powerful disruption methods. Here, we describe such a new method for rapid gene disruption in Y lipolytica. This knockout system combines SEP method and the Cre-lox recombination system, facilitating efficient marker rescue. Versatility was increased by using both auxotrophic markers like ylURA3 and ylLEU2, as well as the antibiotic resistance marker hph. The hph marker, which confers resistance to hygromycin-B, allows gene disruption in a strain lacking any conventional auxothrophic marker. The disruption cassette was shown to integrate at the correct locus at an average frequency of 45%. Upon expression of Cre recombinase, the marker was excised at a frequency of 98%, by recombination between the two lox sites. This new method for gene disruption is an ideal tool for the functional analysis of gene families, or for creating large-scale mutant collections in general. (C) 2003 Elsevier B.V. All rights reserved