1,258 research outputs found
Flexstab on the IBM 360
FLEXSTAB, an array of computer programs developed on CDC equipment, has been converted to operate on the IBM 360 computation system. Instructions for installing, validating, and operating FLEXSTAB on the IBM 360 are included. Hardware requirements are itemized and supplemental materials describe JCL sequences, the CDC to IBM conversion, the input output subprograms, and the interprogram data flow
A continuum of weakly coupled oscillatory McKean neurons
The McKean model of a neuron possesses a one dimensional fast voltage-like variable and a slow
recovery variable. A recent geometric analysis of the singularly perturbed system has allowed an
explicit construction of its phase response curve [S Coombes 2001 Phase-locking in networks of
synaptically coupled McKean relaxation oscillators, Physica D, Vol 160, 173-188]. Here we use
tools from coupled oscillator theory to study weakly coupled networks of McKean neurons. Using
numerical techniques we show that the McKean system has traveling wave phase-locked solutions
consistent with that of a network of more biophysically detailed Hodgkin-Huxley neurons
Oxygen and nitrogen cycling in the northeast Pacific – Simulations and observations at Station Papa in 2003/2004
A long-term air-sea exchange mooring has been maintained in the North Pacific near Ocean Station Papa (OSP, 145W, 50N) since September 2002 as part of the Canadian Surface Ocean Lower Atmosphere Study (C-SOLAS). The mooring provides a new long-term data set for gas measurements. In addition to Conductivity, Temperature and Depth (CTD) recorders at two depths, the mooring is equipped with ProOceanus Gas Tension Devices (GTDs) measuring the total gas pressure at four different depths, two oxygen sensors, two fluorometers for chlorophyll estimates, and an upward-looking 200 kHz echo-sounder for bubble measurements. Chlorophyll data have been added using SeaWiFS imagery and occasional bottle casts. Data collected from June 2003 to June 2004 are compared with simulations from a 1-D coupled atmosphere-ocean-biogeochemical model. The coupled model consists of an atmospheric Single Column Model (SCM), based on the CCCma AGCM (Canadian Centre for Climate Modelling and Analysis-Atmospheric General Circulation Model), the General Ocean Turbulence Model (GOTM) and a 7-component ecosystem model embedded in GOTM. The ecosystem model also includes oxygen, nitrogen, carbon, and silica cycling. The study focuses on simulated and observed N2 and O2 variability. The comparison of these gases allows for separation of physical and biological processes; which can then be evaluated in more detail with the aid of model simulations. The model also tests different parameterizations for saturation and gas exchange, including a formulation for gas injection via bubbles, which affects gas concentrations within the whole mixed layer. For most of the time the model shows good agreement with observations. However, in summer 2003 the observations reveal a strong oxygen and chlorophyll event, which is not reproduced in the standard model run. A weaker signal is seen in May 2004. OSP is a High Nutrient Low Chlorophyll (HNLC) region, limited by the micronutrient iron. Increases in usually low chlorophyll values occur occasionally due to natural iron enrichment (dust deposition, eddy transport, below surface layer transport). Although limitations of 1-D modeling become apparent here, an assumed input of iron in the model explains the differences between simulated and observed oxygen and chlorophyll maxima. The model provides information on the strength and duration of potential iron contribution. No obvious dust events or eddy traverses to supply iron were recorded during this time period. An alternative explanation is entrainment from deeper waters, where occasional iron enrichment is known to occur due to off-shelf transport via eddies or recirculation from the Alaskan shelf
Re-evaluation of Cryptosporiopsis eucalypti and Cryptosporiopsis-like species occurring on Eucalyptus
Cryptosporiopsis eucalypti is a common follicolous pathogen of Eucalyptus species in tropical and temperate regions where these trees are grown in plantations. The taxonomy of C. eucalypti is confused by the fact that it is phylogenetically unrelated to the type species of Cryptosporiopsis (Cryptosporiopsis nigra = C. scutellata, Helotiales). The aim of this study was to resolve the taxonomic position of C. eucalypti based on morphology and phylogenetic inference. Thirty-two Eucalyptus leaf samples with symptoms typical of C. eucalypti infection were collected from 10 tropical and temperate countries across four continents. Cultures were established from single conidia, as well as from ascospores of a previously unreported teleomorph state. DNA sequences were obtained for the 28 S nrDNA, the internal transcribed spacers of the nrDNA operon, and beta-tubulin regions to determine generic and species-level relationships. DNA-sequence analysis showed that conidial and ascospore isolates of C. eucalypti have low intraspecific variation, although two collections from Australia and one from Uruguay represented two novel taxa. Based on the newly collected teleomorph stage, as well as the phylogenetic data, C. eucalypti is shown to represent a new genus closely related to Plagiostoma (Gnomoniaceae, Diaporthales) for which the names Pseudoplagiostoma gen. nov. and Pseudoplagiostomaceae fam. nov. (Diaporthales) are introduced. Two new species of Cryptosporiopsis (Dermateaceae, Helotiales) on Eucalyptus from Australia and California (USA) are also described
Scales of Political Life: Space and Power beyond the Polis
This dissertation considers how geographic scale shapes the theory and practice of politics. It develops a dynamic, relational approach to scale that finds folds and overlaps between micro- and macro-processes. The project asks how subjects negotiate non-concentric political domains: bodies, localities, cities, nations, the globe, and the planet. In contrast to hierarchically nested models of belonging, it emphasizes transnational, transversal, and eccentric forms of ethical and political interconnectedness. Attending to the elaborate interactions between the embodied, local, urban, global, and planetary complicates state-centric images of politics as well as those that present a flattened, reductive approach to globalization.
By tracking an undercurrent in political theory through readings of Machiavelli, Michel Foucault, Michael Hardt, Antonio Negri, David Harvey, and Manuel De Landa, the project renders explicit a theory of scale that has remained at the margins of work on each of these thinkers. It connects this geographic formulation within political theory to bodies of literature focused on the polis, contemporary studies of cities, and urban interconnection. In contrast to predominant approaches to political theory and international relations that privilege either the national or global scale, this project takes the city as the starting point for an inquiry into the ethics and politics of a globalizing world. By selectively emphasizing the political space of the city and its complexities, it pursue the areas of overlap and intersection between multiple scales with rough edges. Urban theorists, such as Harvey and De Landa, have envisioned the city as a multiscalar space. This analysis locates similar tendencies in thinkers less frequently noted for their writings on cities. Machiavelli, Foucault, Hardt, and Negri reflect on the city as a site in which a people, a multiplicity, or a multitude is organized in a world of intersecting scales. The dissertation thus focuses on the city as a strategic point of departure in order to ask how shifts at one scale reverberate through politics elsewhere and how these relations are in turn reflected in the material and social composition of cities
Relationship between self-reported adherence, medication collections and clinical variation in cystic fibrosis
Estimating the health benefits of progeny extraction units as a means of reducing exposure to radon
Radon exposure to the general public can be reduced by preventing entry of radon gas into buildings using a passive radon-proof membrane or an active sump and pump system. However, a significant majority of the radiation dose delivered is from the decay products of radon rather than from the gas itself. These decay products (also referred to as progeny) are present in indoor air, with an equilibrium factor – a measure of the ratio of progeny to radon gas – of between 0.4 to 0.5. As a result, systems which extract radon progeny from the air by filtering have been promoted as means of reducing exposure to the general population.
The European Community Radon Software (ECRS) offers a means of estimating lung-cancer risk associated with an individual’s exposure to radon, and includes the possibility of estimating the health risk from different proportions of radon gas and its progeny by varying the value of the Equilibrium Factor. This software was used to estimate the health benefits associated with reduced decay products in differing concentrations of radon gas. The results were compared to health benefits expected if the risk was reduced by the standard method of reducing the radon gas concentration below the Action Level, which in the UK is 200 Bq·m-3 for domestic properties.
These calculations showed that there is the potential for efficient extraction units to provide the necessary dose and risk reduction where initial average radon gas concentrations are up to 800 Bq·m-3. However, above 1000 Bq·m-3, such systems cannot reduce the health risk sufficiently to reach levels comparable to those resulting from radon gas reduction to below the Action Leve
Variation in lung function as a marker of adherence to oral and inhaled medication in cystic fibrosis
Study aim: The aim of this study was to characterise adherence in an adult population with CF and to investigate if variation in lung function was a predictor of adherence to treatment. Patients and methods: Patients aged ≥ 16 years from an adult CF centre undertook adherence measures by medication possession ratio (MPR) and self-report and were assigned to one of three adherence categories (<50%, 50-<80%, 80% and above) by their composite score (MPR). Ordinal regression was used to identify predictors of adherence including coefficient variation measures for forced expiratory volume in 1 second (FEV1), weight and C-reactive protein, measured up to 6 and 12 months. Results: MPR data for 106 of 249 patients [mean age 29.8 (±9.2) years] was retrieved, indicating a mean adherence of 63%. Coefficient of variation FEV1 was inversely related to adherence and was a univariate predictor of adherence (6 months: 0.92 [0.87-0.98] p= 0.005 and 12 months: 0.94 [0.93-0.99], p=0.03]) and remained significant in the final models. The coefficient variation of weight and C-reactive protein were not predictive of adherence. Conclusions: Coefficient of variation FEV1 was identified as an objective predictor of adherence. Further evaluation of this potential marker of adherence is now required
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