On a class of relatively prime sequences

AbstractFor each natural number n, let a0(n) = n, and if a0(n),…,ai(n) have already been defined, let ai+1(n) > ai(n) be minimal with (ai+1(n), a0(n) … ai(n)) = 1. Let g(n) be the largest ai(n) not a prime or the square of a prime. We show that g(n) ∼ n and that g(n) > n + cn12log(n) for some c > 0. The true order of magnitude of g(n) − n seems to be connected with the fine distribution of prime numbers. We also show that “most” ai(n) that are not primes or squares of primes are products of two distinct primes. A result of independent interest comes of one of our proofs: For every sufficiently large n there is a prime p < n12 with [np] composite

Canine Aortofemoral Bypass: a New Technique for the Evaluation of Prosthetic Implants

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67957/2/10.1177_000331977402500901.pd

Modeling Expert Judgments of Insider Threat Using Ontology Structure: Effects of Individual Indicator Threat Value and Class Membership

We describe research on a comprehensive ontology of sociotechnical and organizational factors for insider threat (SOFIT) and results of an expert knowledge elicitation study. The study examined how alternative insider threat assessment models may reflect associations among constructs beyond the relationships defined in the hierarchical class structure. Results clearly indicate that individual indicators contribute differentially to expert judgments of insider threat risk. Further, models based on ontology class structure more accurately predict expert judgments. There is some (although weak) empirical evidence that other associations among constructs—such as the roles that indicators play in an insider threat exploit—may also contribute to expert judgments of insider threat risk. These findings contribute to ongoing research aimed at development of more effective insider threat decision support tools

A nested case-control study on mortality in uses of ibopamine

Background: A recent interim analysis of the PRIME II placebo-controlled study showed a significantly higher mortality in the group treated with ibopamine than in the control group. The objective was to study mortality in patients on ibopamine, and to assess risk factors for death. Methods: All 2147 drug-dispensing outlets (DDO) in the Netherlands were asked to provide a printout of the complete medication history of users of ibopamine. A reaction was received from 92% of the DDO. From the 14,024 identified former or current users of ibopamine, a sample of 3148 patients (22%) was enrolled in the follow-up study. All general practitioners (GP) of these patients received an enquiry pertaining to the vital status of their patient, cause of death, primary cause and NYHA classification of heart failure, echo- and electrocardiographic data, serum creatinine, admissions and the effects of ibopamine. Cases were defined as patients who died during the follow-u

Enhancement of luminescence by pulse laser annealing of ion-implanted europium in sapphire and silica

Sapphire (Al2O3) and silica samples have been implanted with 400 keV europium ions at fluences between 5×1014 and 1×1016 ions cm-2. As-implanted, samples show luminescence at 622 nm, and although the intensity may be increased by furnace anneals up to 1000°C, higher temperatures, to 1200°C, result in less emission, as the impurity ions form precipitate clusters. This problem can be avoided by the use of pulsed laser anneals which dissociate the clusters and quench in atomically dispersed ions. The luminescence intensity has been increased by factors of 95 and 85 for sapphire and silica, respectively, relative to the initial implanted signal. On comparing with furnace anneals at 1200°C, the pulsed laser annealing is more effective, by factors of up to 45 times. Data for pulsed excimer and CO2 lasers are compared. Both types of laser appear to remove the ion-implanted radiation damage, but in the case of silica, higher luminescence performance was obtained with the excimer anneals. There was no evidence for diffusion of the implanted europium, as assessed by Rutherford backscattering spectrometry. © 1995 American Institute of Physics.We thank Barry Farmery for his help with the RBS work, and both the University of Ege in Turkey and the Science and Engineering Research Council for their financial assistance. We appreciate the use of a Lumonics (Hull Op- erations) Ltd. TEA CO, laser.Peer Reviewe

Density of states in d-wave superconductors disordered by extended impurities

The low-energy quasiparticle states of a disordered d-wave superconductor are investigated theoretically. A class of such states, formed via tunneling between the Andreev bound states that are localized around extended impurities (and result from scattering between pair-potential lobes that differ in sign) is identified. Its (divergent) contribution to the total density of states is determined by taking advantage of connections with certain one-dimensional random tight-binding models. The states under discussion should be distinguished from those associated with nodes in the pair potential.Comment: 5 pages, 1 figur

Vertebral deformities and functional impairment in men and women

Abstract The objective of this study was to assess the prevalence and health effects of vertebral deformities i

Estimating the bispectrum of the Very Small Array data

We estimate the bispectrum of the Very Small Array data from the compact and extended configuration observations released in December 2002, and compare our results to those obtained from Gaussian simulations. There is a slight excess of large bispectrum values for two individual fields, but this does not appear when the fields are combined. Given our expected level of residual point sources, we do not expect these to be the source of the discrepancy. Using the compact configuration data, we put an upper limit of 5400 on the value of f_NL, the non-linear coupling parameter, at 95 per cent confidence. We test our bispectrum estimator using non-Gaussian simulations with a known bispectrum, and recover the input values.Comment: 17 pages, 16 figures, replaced with version accepted by MNRAS. Primordial bispectrum recalculated and figure 11 change