Showing papers by "Queen's University published in 2005"
TL;DR: The addition of temozolomide to radiotherapy for newly diagnosed glioblastoma resulted in a clinically meaningful and statistically significant survival benefit with minimal additional toxicity.
Abstract: methods Patients with newly diagnosed, histologically confirmed glioblastoma were randomly assigned to receive radiotherapy alone (fractionated focal irradiation in daily fractions of 2 Gy given 5 days per week for 6 weeks, for a total of 60 Gy) or radiotherapy plus continuous daily temozolomide (75 mg per square meter of body-surface area per day, 7 days per week from the first to the last day of radiotherapy), followed by six cycles of adjuvant temozolomide (150 to 200 mg per square meter for 5 days during each 28-day cycle). The primary end point was overall survival. results A total of 573 patients from 85 centers underwent randomization. The median age was 56 years, and 84 percent of patients had undergone debulking surgery. At a median follow-up of 28 months, the median survival was 14.6 months with radiotherapy plus temozolomide and 12.1 months with radiotherapy alone. The unadjusted hazard ratio for death in the radiotherapy-plus-temozolomide group was 0.63 (95 percent confidence interval, 0.52 to 0.75; P<0.001 by the log-rank test). The two-year survival rate was 26.5 percent with radiotherapy plus temozolomide and 10.4 percent with radiotherapy alone. Concomitant treatment with radiotherapy plus temozolomide resulted in grade 3 or 4 hematologic toxic effects in 7 percent of patients.
16,653 citations
TL;DR: Elotinib can prolong survival in patients with non-small-cell lung cancer after first-line or second-line chemotherapy, and five percent of patients discontinued erlot inib because of toxic effects.
Abstract: Patients with stage IIIB or IV non–small-cell lung cancer, with performance status from 0 to 3, were eligible if they had received one or two prior chemotherapy regimens. The patients were stratified according to center, performance status, response to prior chemotherapy, number of prior regimens, and prior platinum-based therapy and were randomly assigned in a 2:1 ratio to receive oral erlotinib, at a dose of 150 mg daily, or placebo. results The median age of the 731 patients who underwent randomization was 61.4 years; 49 percent had received two prior chemotherapy regimens, and 93 percent had received platinum-based chemotherapy. The response rate was 8.9 percent in the erlotinib group and less than 1 percent in the placebo group (P<0.001); the median duration of the response was 7.9 months and 3.7 months, respectively. Progression-free survival was 2.2 months and 1.8 months, respectively (hazard ratio, 0.61, adjusted for stratification categories; P<0.001). Overall survival was 6.7 months and 4.7 months, respectively (hazard ratio, 0.70; P<0.001), in favor of erlotinib. Five percent of patients discontinued erlotinib because of toxic effects. conclusions Erlotinib can prolong survival in patients with non–small-cell lung cancer after firstline or second-line chemotherapy.
5,157 citations
TL;DR: The authors examined the cultural and psychological aspects of these phenomena that take place during the process of acculturation, and found that there are large group and individual differences in how people (in both groups in contact) go about their acculture (described in terms of the integration, assimilation, separation and marginalization strategies), in how much stress they experience, and how well they adapt psychologically and socioculturally.
2,742 citations
TL;DR: In this article, a scale to measure the strength of consumers' emotional attachments to brands has been devised, and the scale is positively associated with indicators of both commitment and investment, as well as with satisfaction, involvement, and brand attitudes.
2,143 citations
Durham University1, University of Edinburgh2, ETH Zurich3, Johns Hopkins University4, Queen's University5, Liverpool John Moores University6, University of New South Wales7, Rutherford Appleton Laboratory8, University of Bristol9, Australian National University10, University of Cambridge11, California Institute of Technology12, Australia Telescope National Facility13, University College London14, University of Nottingham15
TL;DR: In this paper, a power-spectrum analysis of the final 2DF Galaxy Redshift Survey (2dFGRS) employing a direct Fourier method is presented, and the covariance matrix is determined using two different approaches to the construction of mock surveys, which are used to demonstrate that the input cosmological model can be correctly recovered.
Abstract: We present a power-spectrum analysis of the final 2dF Galaxy Redshift Survey (2dFGRS), employing a direct Fourier method. The sample used comprises 221 414 galaxies with measured redshifts. We investigate in detail the modelling of the sample selection, improving on previous treatments in a number of respects. A new angular mask is derived, based on revisions to the photometric calibration. The redshift selection function is determined by dividing the survey according to rest-frame colour, and deducing a self-consistent treatment of k-corrections and evolution for each population. The covariance matrix for the power-spectrum estimates is determined using two different approaches to the construction of mock surveys, which are used to demonstrate that the input cosmological model can be correctly recovered. We discuss in detail the possible differences between the galaxy and mass power spectra, and treat these using simulations, analytic models and a hybrid empirical approach. Based on these investigations, we are confident that the 2dFGRS power spectrum can be used to infer the matter content of the universe. On large scales, our estimated power spectrum shows evidence for the ‘baryon oscillations’ that are predicted in cold dark matter (CDM) models. Fitting to a CDM model, assuming a primordial n s = 1 spectrum, h = 0.72 and negligible neutrino mass, the preferred
1,940 citations
TL;DR: Among patients with non-small-cell lung cancer who receive erlotinib, the presence of an EGFR mutation may increase responsiveness to the agent, but it is not indicative of a survival benefit.
Abstract: Background A clinical trial that compared erlotinib with a placebo for non–small-cell lung cancer demonstrated a survival benefit for erlotinib. We used tumor-biopsy samples from participants in this trial to investigate whether responsiveness to erlotinib and its impact on survival were associated with expression by the tumor of epidermal growth factor receptor (EGFR) and EGFR gene amplification and mutations. Methods EGFR expression was evaluated immunohistochemically in non–small-cell lung cancer specimens from 325 of 731 patients in the trial; 197 samples were analyzed for EGFR mutations; and 221 samples were analyzed for the number of EGFR genes. Results In univariate analyses, survival was longer in the erlotinib group than in the placebo group when EGFR was expressed (hazard ratio for death, 0.68; P=0.02) or there was a high number of copies of EGFR (hazard ratio, 0.44; P=0.008). In multivariate analyses, adenocarcinoma (P=0.01), never having smoked (P<0.001), and expression of EGFR (P=0.03) were a...
1,807 citations
TL;DR: Paracrine action accounts for marked protection of ischemic heart by Akt-modified mesenchymal stem cells as discussed by the authors, which was shown to be beneficial for the preservation of the heart.
Abstract: Paracrine action accounts for marked protection of ischemic heart by Akt-modified mesenchymal stem cells
1,531 citations
TL;DR: The role of these four ABC transporter proteins in protecting tissues from a variety of toxicants is discussed and species variations in substrate specificity and tissue distribution of these transporters are addressed since these properties have implications for in vivo models of toxicity used for drug discovery and development.
1,327 citations
TL;DR: The adolescent obesity epidemic is a global issue and increasing physical activity participation and decreasing television viewing should be the focus of strategies aimed at preventing and treating overweight and obesity in youth.
Abstract: The purposes of this systematic review were to present and compare recent estimates of the prevalence of overweight and obesity in school-aged youth from 34 countries and to examine associations between overweight and selected dietary and physical activity patterns. Data consisted of a cross-sectional survey of 137 593 youth (10-16 years) from the 34 (primarily European) participating countries of the 2001-2002 Health Behaviour in School-Aged Children Study. The prevalence of overweight and obesity was determined based on self-reported height and weight and the international child body mass index standards. Logistic regression was employed to examine associations between overweight status with selected dietary and physical activity patterns. The two countries with the highest prevalence of overweight (pre-obese + obese) and obese youth were Malta (25.4% and 7.9%) and the United States (25.1% and 6.8%) while the two countries with the lowest prevalence were Lithuania (5.1% and 0.4%) and Latvia (5.9% and 0.5%). Overweight and obesity prevalence was particularly high in countries located in North America, Great Britain, and south-western Europe. Within most countries physical activity levels were lower and television viewing times were higher in overweight compared to normal weight youth. In 91% of the countries examined, the frequency of sweets intake was lower in overweight than normal weight youth. Overweight status was not associated with the intake of fruits, vegetables, and soft drinks or time spent on the computer. In conclusion, the adolescent obesity epidemic is a global issue. Increasing physical activity participation and decreasing television viewing should be the focus of strategies aimed at preventing and treating overweight and obesity in youth.
1,226 citations
TL;DR: Using data spanning many decades from a once cod-dominated northwest Atlantic ecosystem, a trophic cascade is demonstrated in a large marine ecosystem, suggesting the existence of trophIC cascades in these systems.
Abstract: Removal of top predators from ecosystems can result in cascading effects through the trophic levels below, completely restructuring the food web. Cascades have been observed in small-scale or simple food webs, but not in large, complex, open-ocean ecosystems. Using data spanning many decades from a once cod-dominated northwest Atlantic ecosystem, we demonstrate a trophic cascade in a large marine ecosystem. Several cod stocks in other geographic areas have also collapsed without recovery, suggesting the existence of trophic cascades in these systems.
1,184 citations
TL;DR: A density-functional model depending only on total density, the gradient and Laplacian of the density, and the kinetic-energy density performs as well as the explicitly orbital-dependent model, yet offers obvious computational advantages.
Abstract: We have recently introduced [J. Chem. Phys. 122, 154104 (2005)] a simple parameter-free model of the dispersion interaction based on the instantaneous in space, dipole moment of the exchange hole. The model generates remarkably accurate interatomic and intermolecular C6 dispersion coefficients, and geometries and binding energies of intermolecular complexes. The model involves, in its original form, occupied Hartree-Fock or Kohn-Sham orbitals. Here we present a density-functional reformulation depending only on total density, the gradient and Laplacian of the density, and the kinetic-energy density. This density-functional model performs as well as the explicitly orbital-dependent model, yet offers obvious computational advantages.
TL;DR: In this article, a more comprehensive model of the antecedents of positive word of mouth (WOM) was developed and tested, including consumer identification and commitment, using data obtained from customers of a retailer offering both products and services, finding support for all hypothesized relationships with WOM intentions and/or WOM behaviors as the dependent variable.
Abstract: Empirical studies investigating the antecedents of positive word of mouth (WOM) typically focus on the direct effects of consumers’ satisfaction and dissatisfaction with previous purchasing experiences. The authors develop and test a more comprehensive model of the antecedents of positive. WOM (both intentions and behaviors), including consumer identification and commitment. Specifically, they hypothesize and test commitment as a mediator and moderator of satisfaction on positive WOM and commitment as a mediator of identification on WOM. Using data obtained from customers of a retailer offering both products and services, they find support for all hypothesized relationships with WOM intentions and/or WOM behaviors as the dependent variable. The authors conclude with a discussion of their findings and implications for both marketing theory and practice.
TL;DR: The use of parecoxib and valdecoxib after CABG was associated with an increased incidence of cardiovascular events, arousing serious concern about the use of these drugs in such circumstances.
Abstract: background Valdecoxib and its intravenous prodrug parecoxib are used to treat postoperative pain but may involve risk after coronary-artery bypass grafting (CABG). We conducted a randomized trial to assess the safety of these drugs after CABG. methods In this randomized, double-blind study involving 10 days of treatment and 30 days of follow-up, 1671 patients were randomly assigned to receive intravenous parecoxib for at least 3 days, followed by oral valdecoxib through day 10; intravenous placebo followed by oral valdecoxib; or placebo for 10 days. All patients had access to standard opioid medications. The primary end point was the frequency of predefined adverse events, including cardiovascular events, renal failure or dysfunction, gastroduodenal ulceration, and wound-healing complications. results As compared with the group given placebo alone, both the group given parecoxib and valdecoxib and the group given placebo and valdecoxib had a higher proportion of patients with at least one confirmed adverse event (7.4 percent in each of these two groups vs. 4.0 percent in the placebo group; risk ratio for each comparison, 1.9; 95 percent confidence interval, 1.1 to 3.2; P=0.02 for each comparison with the placebo group). In particular, cardiovascular events (including myocardial infarction, cardiac arrest, stroke, and pulmonary embolism) were more frequent among the patients given parecoxib and valdecoxib than among those given placebo (2.0 percent vs. 0.5 percent; risk ratio, 3.7; 95 percent confidence interval, 1.0 to 13.5; P=0.03). conclusions The use of parecoxib and valdecoxib after CABG was associated with an increased incidence of cardiovascular events, arousing serious concern about the use of these drugs in such circumstances.
TL;DR: Given the clinical significance of multidrug (and drug-specific) exporters, efflux must be considered in formulating strategies/approaches to treating drug-resistant infections, both in the development of new agents less impacted by efflux and in targeting efflux directly with efflux inhibitors.
Abstract: Antibiotic resistance continues to plague antimicrobial chemotherapy of infectious disease. And while true biocide resistance is as yet unrealized, in vitro and in vivo episodes of reduced biocide susceptibility are common and the history of antibiotic resistance should not be ignored in the development and use of biocidal agents. Efflux mechanisms of resistance, both drug specific and multidrug, are important determinants of intrinsic and/or acquired resistance to these antimicrobials, with some accommodating both antibiotics and biocides. This latter raises the spectre (as yet generally unrealized) of biocide selection of multiple antibiotic-resistant organisms. Multidrug efflux mechanisms are broadly conserved in bacteria, are almost invariably chromosome-encoded and their expression in many instances results from mutations in regulatory genes. In contrast, drug-specific efflux mechanisms are generally encoded by plasmids and/or other mobile genetic elements (transposons, integrons) that carry additional resistance genes, and so their ready acquisition is compounded by their association with multidrug resistance. While there is some support for the latter efflux systems arising from efflux determinants of self-protection in antibiotic-producing Streptomyces spp. and, thus, intended as drug exporters, increasingly, chromosomal multidrug efflux determinants, at least in Gram-negative bacteria, appear not to be intended as drug exporters but as exporters with, perhaps, a variety of other roles in bacterial cells. Still, given the clinical significance of multidrug (and drug-specific) exporters, efflux must be considered in formulating strategies/approaches to treating drug-resistant infections, both in the development of new agents, for example, less impacted by efflux and in targeting efflux directly with efflux inhibitors.
TL;DR: Asymmetric Incremental Sheet Forming has the potential to revolutionize sheet metal forming, making it accessible to all levels of manufacturing as discussed by the authors, and has been shown to be a state-of-the-art in sheet metal manufacturing.
TL;DR: This new index contains diagnoses such as arthritis not found on indices used to Predict mortality, and the FCI explained more variance in PF scores compared to indices designed to predict mortality.
TL;DR: In this paper, the authors present updated evidence suggesting that mixed mating systems are frequent in seed plants and outline the floral and pollination mechanisms that can lead to intermediate outcrossing.
Abstract: ▪ Abstract Mixed mating, in which hermaphrodite plant species reproduce by both self- and cross-fertilization, presents a challenging problem for evolutionary biologists. Theory suggests that inbreeding depression, the main selective factor opposing the evolution of selfing, can be purged with self-fertilization, a process that is expected to yield pure strategies of either outcrossing or selfing. Here we present updated evidence suggesting that mixed mating systems are frequent in seed plants. We outline the floral and pollination mechanisms that can lead to intermediate outcrossing, review the theoretical models that address the stability of intermediate outcrossing, and examine relevant empirical evidence. A comparative analysis of estimated inbreeding coefficients and outcrossing rates suggests that mixed mating often evolves despite strong inbreeding depression. The adaptive significance of mixed mating has yet to be fully explained for any species. Recent theoretical and empirical work suggests that...
TL;DR: Gabapentin and morphine combined achieved better analgesia at lower doses of each drug than either as a single agent, with constipation, sedation, and dry mouth as the most frequent adverse effects.
Abstract: From the Departments of Anesthesiology (I.G., J.M.B.) and Pharmacology and Tox- icology (I.G.), the Departments of Mathe- matics and Statistics and Community Health and Epidemiology (D.T.), the De- partment of Psychology (R.R.H.), and the Department of Medicine (Division of En- docrinology) (R.L.H.), Queen's Universi- ty, Kingston, Ont.; and the Departments background The available drugs to treat neuropathic pain have incomplete efficacy and dose-limit- ing adverse effects. We compared the efficacy of a combination of gabapentin and mor- phine with that of each as a single agent in patients with painful diabetic neuropathy or postherpetic neuralgia. methods In this randomized, double-blind, active placebo-controlled, four-period crossover trial, patients received daily active placebo (lorazepam), sustained-release morphine, gabapentin, and a combination of gabapentin and morphine — each given orally for five weeks. The primary outcome measure was mean daily pain intensity in patients re- ceiving a maximal tolerated dose; secondary outcomes included pain (rated according to the Short-Form McGill Pain Questionnaire), adverse effects, maximal tolerated dos- es, mood, and quality of life. results abstract
TL;DR: Fifty-five paleolimnological records from lakes in the circumpolar Arctic reveal widespread species changes and ecological reorganizations in algae and invertebrate communities since approximately anno Domini 1850, indicating that the opportunity to study arctic ecosystems unaffected by human influences may have disappeared.
Abstract: Fifty-five paleolimnological records from lakes in the circumpolar Arctic reveal widespread species changes and ecological reorganizations in algae and invertebrate communities since approximately anno Domini 1850. The remoteness of these sites, coupled with the ecological characteristics of taxa involved, indicate that changes are primarily driven by climate warming through lengthening of the summer growing season and related limnological changes. The widespread distribution and similar character of these changes indicate that the opportunity to study arctic ecosystems unaffected by human influences may have disappeared.
TL;DR: A switchable solvents system that converts to an ionic liquid upon exposure to an atmosphere of carbon dioxide, and then reverts back to its non-ionic form when exposed to nitrogen or argon gas is created.
Abstract: Imagine a smart solvent that can be switched reversibly from a liquid with one set of properties to another that has very different properties, upon command. Here we create such a system, in which a non-ionic liquid (an alcohol and an amine base) converts to an ionic liquid (a salt in liquid form) upon exposure to an atmosphere of carbon dioxide, and then reverts back to its non-ionic form when exposed to nitrogen or argon gas. Such switchable solvents should facilitate organic syntheses and separations by eliminating the need to remove and replace solvents after each reaction step.
TL;DR: Trust in management and perceived safety climate were found to mediate the relationship between an HPWS and safety performance measured in terms of personal-safety orientation and safety incidents.
Abstract: Two studies were conducted investigating the relationship between high-performance work systems (HPWS) and occupational safety. In Study 1, data were obtained from company human resource and safety directors across 138 organizations. LISREL VIII results showed that an HPWS was positively related to occupational safety at the organizational level. Study 2 used data from 189 front-line employees in 2 organizations. Trust in management and perceived safety climate were found to mediate the relationship between an HPWS and safety performance measured in terms of personal-safety orientation (i.e., safety knowledge, safety motivation, safety compliance, and safety initiative) and safety incidents (i.e., injuries requiring first aid and near misses). These 2 studies provide confirmation of the important role organizational factors play in ensuring worker safety.
TL;DR: A post-Hartree-Fock model in which C6 coefficients are generated by the instantaneous dipole moment of the exchange hole, and involves only one, universal, empirical parameter to limit the dispersion energy at small interatomic separations.
Abstract: Intermolecular interactions are of great importance in chemistry but are difficult to model accurately with computational methods. In particular, Hartree–Fock and standard density-functional approximations do not include the physics necessary to properly describe dispersion. These methods are sometimes corrected to account for dispersion by adding a pairwise C6∕R6 term, with C6 dispersion coefficients dependent on the atoms involved. We present a post-Hartree–Fock model in which C6 coefficients are generated by the instantaneous dipole moment of the exchange hole. This model relies on occupied orbitals only, and involves only one, universal, empirical parameter to limit the dispersion energy at small interatomic separations. The model is extensively tested on isotropic C6 coefficients of 178 intermolecular pairs. It is also applied to the calculation of the geometries and binding energies of 20 intermolecular complexes involving dispersion, dipole-induced dipole, dipole–dipole, and hydrogen-bonding intera...
TL;DR: In this paper, the applicability of a model of migration from the human geography literature as a unifying, theoretical framework for understanding consumers' service provider switching behaviors was explored, and survey data from approximately 700 consumers were used to examine the usefulness of the push, pull, and moorings (PPM) migration model.
Abstract: This article explores the applicability of a model of migration from the human geography literature as a unifying, theoretical framework for understanding consumers’ service provider switching behaviors. Survey data from approximately 700 consumers are used to examine the usefulness of the push, pull, and moorings (PPM) migration model. The PPM migration model performs better than an alternative model; all three categories of antecedents to switching (migration)—push, pull, and mooring variables—have significant direct, and some moderating, effects on switching intentions.
TL;DR: The results are not uniformly positive, and the reasons for this remain unexplained, but glucosamine was superior to placebo in the treatment of pain and functional impairment resulting from symptomatic OA.
Abstract: What is osteoarthritis and glucosamine?
Osteoarthritis (OA) is the most common form of arthritis that can affect the hands, hips, shoulders and knees. In OA, the cartilage that protects the ends of the bones breaks down and causes pain and swelling. Drug and non-drug treatments are used to relieve pain and/or swelling.
Glucosamine can be found naturally in the body and is used by the body as one of the building blocks of cartilage. Glucosamine can also be taken as a pill as a supplement to the diet, or sometimes as an injection. It can come in combination with other supplements (such as chondroitin), or by itself in the form of glucosamine hydrochloride or sulphate. The usual dose recommended on packages is 1500 mg per day or 500 mg three times a day.
In Europe, glucosamine is prescribed by health care providers. But in North America, people can buy glucosamine supplements without a prescription. This means that, in North America, glucosamine is not regulated and the pills may or may not truly contain the amount described on the label.
Best estimate of what happens after about 6 months
Pain: The high quality studies showed that pain improved about the same whether people took glucosamine or fake pills. If all of the studies are examined (including low quality and old studies), then glucosamine improved pain more than fake pills.
People who took fake pills had a pain score of 7 points on a 0 to 100 scale. Pain may improve by 10 more points with glucosamine than with fake pills.
Studies testing only the Rotta brand of glucosamine (including low quality and older studies) showed that glucosamine improved pain more than fake pills. People who took fake pills had a pain score of 6 points on a 0 to 20 scale. People who took the Rotta brand of glucosamine rated their pain 3 points lower than people who did not take glucosamine.
Function: The high quality studies show that glucosamine improved function more than fake pills when measured by one type of scale, but improved the same amount as fake pills when measured by another scale.
Studies testing only the Rotta brand of glucosamine (including low quality and older studies) showed that glucosamine improved function more than fake pills. People who took fake pills had a function score of 22 points on a 0 to 68 scale. People who took the Rotta brand of glucosamine had their ability to function improve by 2 points compared to people who did not take glucosamine.
There was no difference in the number of people who had side effects. Side effects mainly included stomach upset and other joint pain.
TL;DR: Adopting a life stress perspective, the authors introduce 3 major themes that resolve the inconsistencies in the current literature and extrapolate these themes to develop a preliminary framework for evaluating competing explanatory models and to guide research on life stress and the recurrence of depression.
Abstract: Major depression is frequently characterized by recurrent episodes over the life course. First lifetime episodes of depression, however, are typically more strongly associated with major life stress than are successive recurrences. A key theoretical issue involves how the role of major life stress changes from an initial episode over subsequent recurrences. The primary conceptual framework for research on life stress and recurrence of depression is the "kindling" hypothesis (R. M. Post, 1992). Despite the strengths of the kindling hypothesis, a review of the research literature reveals inconsistencies and confusion about life stress and its implications for the recurrence of depression. Adopting a life stress perspective, the authors introduce 3 major themes that resolve the inconsistencies in the current literature. They integrate these themes and extrapolate the ideas with available data to develop a preliminary framework for evaluating competing explanatory models and to guide research on life stress and the recurrence of depression.
TL;DR: The mechanisms of FMD depend on the nature of the shear stress stimulus (stimulus response specificity), an update to the current guidelines for FMD assessment is provided, and the issues that surround the clinical utility of measuring both NO‐ and non‐NO‐mediated FMD are summarized.
Abstract: Endothelium-dependent flow-mediated dilatation (FMD) describes the vasodilatory response of a vessel to elevations in blood flow-associated shear stress. Nitric oxide (NO), one of many vasoactive substances released by the endothelium in response to shear stress, is of particular interest to researchers as it is an antiatherogenic molecule, and a reduction in its bioavailability may play a role in the pathogenesis of vascular disease. The goal of many human studies is to create a shear stress stimulus that produces an NO-dependent response in order to use the FMD measurements as an assay of NO bioavailability. The most common non-invasive technique is the 'reactive hyperaemia test' which produces a large, transient shear stress profile and a corresponding FMD. Importantly, not all FMD is NO mediated and the stimulus creation technique is a critical determinant of NO dependence. The purpose of this review is to (1) explain that the mechanisms of FMD depend on the nature of the shear stress stimulus (stimulus response specificity), (2) provide an update to the current guidelines for FMD assessment, and (3) summarize the issues that surround the clinical utility of measuring both NO- and non-NO-mediated FMD. Future research should include (1) the identification and partitioning of mechanisms responsible for FMD in response to various shear stress profiles, (2) investigation of stimulus response specificity in coronary arteries, and (3) investigation of non-NO FMD mechanisms and their connection to the development of vascular disease and occurrence of cardiovascular events.
TL;DR: The general applicability of the autoregressive stochastic models method is demonstrated by examples involving the accurate synthesis of nonisotropic fading channel models, and performance comparisons are made with popular fading generation techniques.
Abstract: Autoregressive stochastic models for the computer simulation of correlated Rayleigh fading processes are investigated. The unavoidable numerical difficulties inherent in this method are elucidated and a simple heuristic approach is adopted to enable the synthesis of accurately correlated, bandlimited Rayleigh variates. Startup procedures are presented, which allow autoregressive simulators to produce stationary channel gain samples from the first output sample. Performance comparisons are then made with popular fading generation techniques to demonstrate the merits of the approach. The general applicability of the method is demonstrated by examples involving the accurate synthesis of nonisotropic fading channel models.
TL;DR: Present evidence suggests that the Ediacara biota included a mixture of stem- and crown-group radial animals, stem-group bilaterian animals, “failed experiments” in animal evolution, and perhaps representatives of other eukaryotic kingdoms.
Abstract: ▪ Abstract The Ediacara biota (575–542 Ma) marks the first appearance of large, architecturally complex organisms in Earth history. Present evidence suggests that the Ediacara biota included a mixture of stem- and crown-group radial animals, stem-group bilaterian animals, “failed experiments” in animal evolution, and perhaps representatives of other eukaryotic kingdoms. These soft-bodied organisms were preserved under (or rarely within) event beds of sand or volcanic ash, and four distinct preservational styles (Flinders-, Fermeuse-, Conception-, and Nama-style) profoundly affected the types of organisms and features that could be preserved. Even the earliest Ediacaran communities (575–565 Ma) show vertical and lateral niche subdivision of the sessile, benthic, filter-feeding organisms, which is strikingly like that of Phanerozoic and modern communities. Later biological and ecological innovations include mobility (>555 Ma), calcification (550 Ma), and predation (<549 Ma). The Ediacara biota abruptly disa...
TL;DR: A simple model is presented in which the instantaneous dipole moment of the exchange hole is used to generate a dispersion interaction between nonoverlapping systems and the resulting C6 dispersion coefficients are remarkably accurate.
Abstract: A simple model is presented in which the instantaneous dipole moment of the exchange hole is used to generate a dispersion interaction between nonoverlapping systems. The model is easy to implement, requiring no electron correlation (in the usual sense) or time dependence, and has been tested on various atomic and molecular pairs. The resulting C6 dispersion coefficients are remarkably accurate.