343 research outputs found

    Parity results on connected Æ’-factors

    Get PDF
    AbstractLet G be a connected graph with vertex set V and let d(ν) denote the degree of a vertex νϵV. For ƒ a mapping from V to the positive integers, an ƒ-factor is a spanning subgraph having degree ƒ(ν) at vertex ν. In this paper we extend the parity results of Thomason [2] on Hamiltonian circuits to connected ƒ-factors. (A Hamiltonian circuit is a connected 2-factor.) We show that if ƒ(ν) and d(ν) have opposite parity for all νϵV then for any given subgraph C there is an even number of connected ƒ-factors having C as a cotree.Let ƒ1 and ƒ2 be any mappings from V to the positive integers that partition d, i.e., d(ν) = ƒ1(ν) +ƒ2(ν) for all νϵV. Let C1 and C2 be any pair of edge disjoint subgraphs. We also show in this paper that the number of decompositions of G into a connected ƒ1-factor having C1 as a cotree and a connected ƒ2-factor having C2 as a cotree is even

    Three-colourings of planar 4-valent maps

    Get PDF
    AbstractA strong face 3-colouring of a planar 4-valent map G is a 3-colouring of the faces such that there is a face of each colour at every vertex. Such a map is one-track if it contains an Eulerian path which at each vertex regarded as a cross-roads goes directly through. It is proved that every planar 4-valent map can be strongly face 3-coloured and this can be done in a unique way if and only if G is one-track. Formulas are obtained for the number of strong face 3-colourings and the number of all face 3-colourings

    Verifiable broadcasting and gossiping in communication networks

    Get PDF
    AbstractIn network communication where messages may be corrupted in transmission, one way to verify the correctness of a given message is to arrange for nodes in the network to receive the message multiple times. For example, in broadcasting (one-to-all communication) from a given source node u, if a message sent by u is received by all other nodes at least k+1 times, then each node can perform k checks against the original message to verify that it has not been corrupted in transmission. Similar behavior would be useful for gossiping (all-to-all communication) where information held in each node is to be communicated to all other nodes. For an n-node network, we consider the problem of determining the minimum number of network links required to support this k-fold verifiability. We show that the minimum size β(n,k) of an n-vertex k-verifiable broadcast scheme is given by β(n,k)=⌈(k+2)(n−1)/2⌉. We also show that the minimum size γ(n,k) of an n-vertex k-verifiable gossip scheme satisfies ⌈(k+4)(n−1)/2⌉−⌊log2n⌋⩽γ(n,k)⩽⌈(k+4)n/2⌉−4. The value for β(n,k) and lower bound for γ(n,k) yield lower bounds for the size of a k-fault tolerant broadcast and gossip scheme which meet and improve, respectively, the previously known lower bounds for these schemes

    Effective risk stratification using exercise myocardial perfusion SPECT in women: Gender-related differences in prognostic nuclear testing

    Get PDF
    AbstractObjectives. This study was designed to evaluate the incremental prognostic value over clinical and exercise variables of rest thallium-201/exercise technetium-99m sestamibi single-photon emission computed tomography (SPECT) in women compared with men and to determine whether this test can be used to effectively risk stratify patients of both genders.Background. To minimize the previously described gender-related bias in the evaluation of coronary artery disease in women, there is a need to identify a noninvasive testing strategy that is able to accurately and effectively risk stratify women.Methods. We identified 4,136 consecutive patients (2,742 men, 1,394 women) who underwent dual-isotope SPECT. The incremental value of nuclear testing was determined using both a stepwise Cox proportional hazards model and Kaplan-Meier survival analysis. Receiver operating characteristic curve analysis was performed to determine test discrimination for high risk patients in men and women.Results. The patient population was followed up for 20 ± 5 months for events (cardiac death or nonfatal myocardial infarction). During this time, 63 myocardial infarctions and 32 cardiac deaths occurred in the men, and 31 myocardial infarctions and 14 cardiac deaths occurred in the women. Nuclear testing significantly stratified both men and women irrespective of their rest electrocardiogram. Cox proportional hazards analysis revealed that nuclear testing added incremental prognostic value in both men and women after inclusion of the most predictive clinical and exercise variables (overall chi-square 89 in men vs. 120 in women, p < 0.005). Kaplan-Meier survival analysis demonstrated that nuclear testing further stratified men and women with both intermediate to high and low prescan likelihoods of coronary artery disease (p < 0.005 for all). Receiver operating characteristic curve analysis demonstrated superior discrimination for the nuclear scan results in identifying high risk women than men (area under the curve: 0.84 ± 0.03 vs. 0.71 ± 0.03 in men, p < 0.0005). The odds ratio comparing event rates in patients with abnormal versus those with normal scan results was greater in women than in men, suggesting superior stratification using nuclear testing in women.Conclusions. Dual-isotope myocardial perfusion imaging yields incremental prognostic value in both men and women. This modality identifies low risk women and men equally well but relatively high risk women more accurately than relatively high risk men and, thus, is able to stratify women more effectively than men

    A systematic, intensive statistical investigation of data from the Comprehensive Analysis of Reported Drugs (CARD) for compliance and illicit opioid abstinence in substance addiction treatment with buprenorphine/naloxone

    Get PDF
    BACKGROUND: Buprenorphine and naloxone (bup/nal), a combination partial mu receptor agonist and low-dose delta mu antagonist, is presently recommended and used to treat opioid-use disorder. However, a literature review revealed a paucity of research involving data from urine drug tests that looked at compliance and abstinence in one sample. METHOD: Statistical analysis of data from the Comprehensive Analysis of Reported Drugs (CARD) was used to assess compliance and abstinence during treatment in a large cohort of bup/nal patients attending chemical-dependency programs from eastern USA in 2010 and 2011. RESULTS: Part 1: Bup/nal was present in 93.4% of first (n = 1,282; p \u3c.0001) and 92.4% of last (n = 1,268; p \u3c.0001) urine samples. Concomitantly, unreported illicit drugs were present in 47.7% (n = 655, p =.0261) of samples. Patients who were compliant to the bup/nal prescription were more likely than noncompliant patients to be abstinent during treatment (p =.0012; odds ratio = 1.69 with 95% confidence interval (1.210, 2.354). Part 2: An analysis of all samples collected in 2011 revealed a significant improvement in both compliance (p \u3c 2.2 × 1

    Genomic diversity, chromosomal rearrangements, and interspecies hybridization in the Ogataea polymorpha species complex

    Get PDF
    The methylotrophic yeast Ogataea polymorpha has long been a useful system for recombinant protein production, as well as a model system for methanol metabolism, peroxisome biogenesis, thermotolerance, and nitrate assimilation. It has more recently become an important model for the evolution of mating-type switching. Here, we present a population genomics analysis of 47 isolates within the O. polymorpha species complex, including representatives of the species O. polymorpha, Ogataea parapolymorpha, Ogataea haglerorum, and Ogataea angusta. We found low levels of nucleotide sequence diversity within the O. polymorpha species complex and identified chromosomal rearrangements both within and between species. In addition, we found that one isolate is an interspecies hybrid between O. polymorpha and O. parapolymorpha and present evidence for loss of heterozygosity following hybridization

    Community syndicalism for the United States: preliminary observations on law and globalization in democratic production

    Get PDF
    two structural labor crises for developed economies: 1) The channeling of substantial investment into non-productive, paper commodities, reducing growth of production for use and therefore reducing available aggregate job creation; and 2) The continued exportation of industrial jobs to other lower cost jurisdictions, and outsourcing, automation, just-in-time production, and speed-ups associated with global supply chains. As a result, local communities and regional populations have destabilized and even collapsed with attendant social problems. One possible response is Community Syndicalism – local community finance and operating credit for industrial production combined with democratic worker ownership and control of production. The result would increase investment directly for production, retain jobs in existing population centers, promote job skilling, and retain tax bases for local services and income supporting local businesses, at the same time increasing support for authentic political democracy by rendering the exploitive ideology of the Public/Private distinction superfluous. Slowing job exportation may reduce the global race to the bottom of labor standards and differential wage rates reducing the return to producers of value and increasing the skew of income distribution undermining social wages and welfare worldwide. Community Syndicalism can serve as moral goal in an alternative production model focusing incentives on long term stability of jobs and community economic base

    Identification of a CpG Island Methylator Phenotype that Defines a Distinct Subgroup of Glioma

    Get PDF
    SummaryWe have profiled promoter DNA methylation alterations in 272 glioblastoma tumors in the context of The Cancer Genome Atlas (TCGA). We found that a distinct subset of samples displays concerted hypermethylation at a large number of loci, indicating the existence of a glioma-CpG island methylator phenotype (G-CIMP). We validated G-CIMP in a set of non-TCGA glioblastomas and low-grade gliomas. G-CIMP tumors belong to the proneural subgroup, are more prevalent among lower-grade gliomas, display distinct copy-number alterations, and are tightly associated with IDH1 somatic mutations. Patients with G-CIMP tumors are younger at the time of diagnosis and experience significantly improved outcome. These findings identify G-CIMP as a distinct subset of human gliomas on molecular and clinical grounds

    The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

    Get PDF
    The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure
    • …
    corecore