On the t-Term Rank of a Matrix

For t a positive integer, the t-term rank of a (0,1)-matrix A is defined to be the largest number of 1s in A with at most one 1 in each column and at most t 1s in each row. Thus the 1-term rank is the ordinary term rank. We generalize some basic results for the term rank to the t-term rank, including a formula for the maximum term rank over a nonempty class of (0,1)-matrices with the the same row sum and column sum vectors. We also show the surprising result that in such a class there exists a matrix which realizes all of the maximum terms ranks between 1 and t.Comment: 18 page

Cyclic Matching Sequencibility of Graphs

We define the cyclic matching sequencibility of a graph to be the largest integer $d$ such that there exists a cyclic ordering of its edges so that every $d$ consecutive edges in the cyclic ordering form a matching. We show that the cyclic matching sequencibility of $K_{2m}$ and $K_{2m+1}$ equal $m-1$

A METHODOLOGY FOR CLASSIFYING THE COMPLEXITY OF EXPERT SYSTEMS: A PILOT STUDY

The focus of this paper is to present a classification methodology for evaluating the complexity of expert systems. Complexity in the area of expert systems consists of two basic dimensions: the complexity of the underlying knowledge residing with the experts and the complexity of the technology incorporated into a given system. The classification methodology was developed and tested for its ability to accurately differentiate expert systems with a pilot sample of six expert systems. Using this approach provides a basis for managers to assess the complexity of a particular expert system and thereby assist in planning the scope of the development and implementation effort and the fit of a particular project with the firm\u27s internal resources and the needs of its competitive environment

Organizing For the Effective Diffusion of Corporate Information Systems: Manage Project Scale and Scope

Incremental innovations reinforce the capability of established organizations, while radical innovations cause firms to develop new technical and commercial skills. In this paper, we will present the results of an exploratory study examining the technology diffusion process associated with eleven different systems initiatives in eight organizations and suggest that, in addition to the important distinctions the technology life cycle model provides, another useful perspective is that one differentiates the innovation based on its scale and scope. We will present the findings of this exploratoryresearch and suggest that to successfully diffuse projects of different scale and scope requires the building of differentiated project selection processes and criteria, organizational structures and management involvement. As a first step in this process, we propose classifying R&D initiatives based on scale and scope and suggest that this classification will enable managers to identify and establish appropriate managerial and organizational processes that will facilitate the technology diffusion

Body Composition Measurement in Children with Cerebral Palsy, Spina Bifida and Spinal Cord Injury: A Systematic Review of the Literature

Pediatric obesity is a major health concern that has an increased prevalence in children with special needs. In order to categorize a child’s weight, an assessment of body composition is needed. Obtaining an accurate body composition measurement in children with special needs has many challenges associated with it. This perplexing scenario limits the provider’s ability to screen, prevent and treat an abnormal weight status in this vulnerable population. This systematic review summarizes common methods of body composition measurements, their strengths and limitations and reviews the literature when measurements were used in children with cerebral palsy, spina bifida and spinal cord injury. Following PRISMA guidelines, 222 studies were identified. The application of the inclusion and exclusion criteria yielded a final sample of nine studies included in this review. Overall, articles reinforced the inconsistencies of body composition measurement and methodology when used with children with special needs. Concerns include small sample sizes, the need to validate prediction equations for this population, and the lack of controlled trials and reporting of measurement methodology. Healthcare providers need to be aware of the complexities associated with measuring body composition in children with special needs and advocate for further testing of these measurements. Additional studies addressing the reliability and validity of these measures are needed to facilitate appropriate health promotion in children

Using a candidate gene approach to identify the restorer-of-fertility Rf4 gene for maize CMS-C

Abstract only availableCytoplasmic male sterility (CMS) is a maternally inherited trait that prevents normal pollen development. Although CMS is a mitochondrial mutation, there are nuclear genes known as restorer-of-fertility genes (Rf) that restore normal pollen development. This makes CMS particularly useful in performing controlled crosses for plant breeding programs and seed production, where the desired female carries a CMS mutation and the male contains the nuclear Rf gene. In maize, CMS type C (CMS-C) can be restored to fertility by the Rf4 gene. Identification of Rf4 can provide insight into the cause of CMS-C pollen abortion, and expand our knowledge of nuclear-mitochondrial communication. Our approach for identifying Rf4 combines genetic information with the physical maps and emerging DNA sequence data. Previous studies have genetically mapped the Rf4 gene to the short arm of a chromosome 8 (Sisco, 1991). Our goal is to identify a candidate gene for Rf4 in the correct region of chromosome 8. Genes in this region were categorized based on the probability of the proteins to be targeted to the mitochondria using MitoPROT and Predotar. The genes were also analyzed for PPR motifs using TPRpred. We used the criteria of mitochondrial targeting and a probable PPR functional motif because most Rf genes identified to date are targeted to mitochondria and have a PPR motif in their sequence. Primers have been designed for candidate genes, and they will be amplified and sequenced from six different maize inbred lines: three with the fertility restoring allele Rf4 and the non-restoring allele rf4. The sequenced genes will be then analyzed for nucleotide polymorphisms that correlate with the Rf4 and rf4 alleles.NSF Plant Genomics Internship @ M

Altered nuclear gene expression in response to mitochondrial mutations in maize [abstract]

Abstract only availableMaize non-chromosomal stripe (NCS) plants are defective plants with mutations within mitochondrial DNA (mtDNA) resulting in deficiencies in the electron transfer chain (ETC). It has been shown the cells will synthesize nuclear proteins in response to the mitochondrial mutations. All NCS mutants are known to up-regulate several stress proteins in response to defective mitochondria, including alternative oxidases and heat shock proteins. Changes in RNA levels can indicate which proteins differ in expression. The NCS2 has a mutation within complex I of the ETC. Using microarrays, total RNA samples of the NCS2 mutant are being compared to those of relatives with normal mitochondria. So far, many differences in RNA levels have been observed. Data is still being collected and being analyzed to determine how many of the apparent differences are statistically significant.MU Monsanto Undergraduate Research Fellowshi

Circular and linear mitochondrial genomes in cytoplasmic male sterile maize [abstract]

Abstract only availableCytoplasmic male sterility (CMS) is a maternally inherited condition in which a plant has an inability to produce viable pollen. It is usually due to the production of a toxic chimeric protein within the mitochondria during the maturation of pollen grains. In maize (Zea mays), there are three types of CMS: CMS-T, CMS-C and CMS-S. The S-type of cytoplasmic male sterility (CMS-S) in maize is associated with the expression of a rearranged mitochondrial DNA region. This CMS-S-specific region includes two co-transcribed chimeric open reading frames, orf355 and orf77. The nuclear restorer-of-fertility gene, Rf3, cleaves all transcripts containing both orfs, including the CMS-S-specific linear 1.6 kb mRNA; this results in male fertility. The Lancaster Surecrop-derived inbred line A619 carries a different and weaker restorer called Rf9. Fertility restoration by Rf3 and Rf9 was compared for their effects upon the CMS-associated region of mitochondrial DNA. Unlike Rf3, Rf9 affects the organization of the CMS-S-specific region. It appears to do this by affecting recombination between linear "S" plasmids and the CMS-S-specific region of the main mitochondrial genome, which produces a linear end from which transcripts for the 1.6 kb mRNA are initiated. By reducing the amount of recombination, Rf9 reduces the amount of linear template available for transcribing the S-associated 1.6 kb RNA. A reduction in this transcript is associated with an increase in pollen survival. We have studied the effects of the two restorer-of-fertility genes from several different inbred lines on the amounts of integrated and linearized orf355/orf77 genes within CMS-S mtDNA.MU Monsanto Undergraduate Research Fellowshi

The microbiome of ancient ice wedges in the Muostakh ‘disappearing island’

Climate change-driven thermal erosion makes Muostakh Island in the southern Laptev Sea (70°35´ N, 130° 0´ E) a very fragile ecosystem of the Arctic. Thus, understanding its biodiversity, the changes and loss in response to climate is a timely and pressing scientific objective. Here, we characterize the microbiome associated with several ice wedges covering the past ~45,000 years of climate/ecosystem history. Ice wedges are a specific feature in the northern permafrost landscapes. They develop seasonally by spring-melting of snow that runs through permafrost contraction cracks, accumulates and creates ice formations in the wintertime through congelifraction. Such environment offers ideal conditions for the preservation of microbial cells and DNA over geological time. Our work tackles four main research aspects, requiring an interdisciplinary approach with synergies between microbial ecology, geo- and paleo-sciences. First, we characterize the ice wedge mineral composition as an environmental micro-niche. Second, we analyze the biodiversity of the microbial communities via shotgun metagenomics of the ancient DNA (aDNA) extracted from the ice wedges. Third, we investigate the biomass content by recovering and enumerating microbial cells present in the ice wedges. In addition, we apply infrared spectroscopy to obtain cellular fingerprints that can serve as biomarkers. Finally, we assess the physiological state of microorganisms using stable isotope probing (SIP) experiments in microcosms that reproduce the environmental conditions (subzero temperature and anoxic conditions). By integrating microbial biodiversity with activity and environmental context, this study will provide valuable new insights into Muostakh’s ice wedge microbiome and the dynamics underlying its changes over time and climatic conditions