5,071 research outputs found

    Location and Landscape in Literary Americanisms: H. L. Davis and F. Scott Fitzgerald

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    Well into the twentieth century, western American literature was still dismissed as regional or was boxed in by the genre expectations of pulp Westerns. This chapter focuses less on the causes of an eastern dismissal of western literature and more on what is unique about western literature, including how it reflects the larger western experience. Sumner looks at the particular Americanisms evident in the letters of the American West, using two short stories to make his argument: H. L. Davis’s Open Winter and F. Scott Fitzgerald’s Babylon Revisited

    The role of Computer Aided Process Engineering in physiology and clinical medicine

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    This paper discusses the potential role for Computer Aided Process Engineering (CAPE) in developing engineering analysis and design approaches to biological systems across multiple levels—cell signalling networks, gene, protein and metabolic networks, cellular systems, through to physiological systems. The 21st Century challenge in the Life Sciences is to bring together widely dispersed models and knowledge in order to enable a system-wide understanding of these complex systems. This systems level understanding should have broad clinical benefits. Computer Aided Process Engineering can bring systems approaches to (i) improving understanding of these complex chemical and physical (particularly molecular transport in complex flow regimes) interactions at multiple scales in living systems, (ii) analysis of these models to help to identify critical missing information and to explore the consequences on major output variables resulting from disturbances to the system, and (iii) ‘design’ potential interventions in in vivo systems which can have significant beneficial, or potentially harmful, effects which need to be understood. This paper develops these three themes drawing on recent projects at UCL. The first project has modeled the effects of blood flow on endothelial cells lining arteries, taking into account cell shape change resulting in changes in the cell skeleton which cause consequent chemical changes. A second is a project which is building an in silico model of the human liver, tieing together models from the molecular level to the liver. The composite model models glucose regulation in the liver and associated organs. Both projects involve molecular transport, chemical reactions, and complex multiscale systems, tackled by approaches from CAPE. Chemical Engineers solve multiple scale problems in manufacturing processes – from molecular scale through unit operations scale to plant-wide and enterprise wide systems – so have an appropriate skill set for tackling problems in physiology and clinical medicine, in collaboration with life and clinical scientists

    Sensitivity analysis in systems biology modelling and its application to a multi-scale model of blood glucose homeostasis

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    Biological systems typically consist of large numbers of interacting components and involve processes at a variety of spatial, temporal and biological scales. Systems biology aims to understand such systems by integrating information from all functional levels into a single cohesive model. Mathematical and computational modelling is a key part of the systems biology approach and can be used to produce composite models which describe systems across multiple scales. One of the major diculties in constructing models of biological systems is the lack of precise parameter values which are often associated with a high degree of uncertainty. This uncertainty in parameter values can be incorporated into the modelling process using sensitivity analysis, the systematic investigation of the relationship between uncertain model inputs and the resulting variation in the model outputs. This thesis discusses the use of global sensitivity analysis in systems biology modelling and addresses two main problem areas: the application of sensitivity analysis to time dependent model outputs and the analysis of multi-scale models. An approach to the analysis of time dependent model outputs which makes use of principal component analysis to extract the key modes of variation from the data, is presented. The analysis of multi-scale models is addressed using group-based sensitivity analysis which enables the identication of the most important sub-processes in the model. Together these methods provide a new methodology for sensitivity analysis in multi-scale systems biology modelling. The methodology is applied to a composite model of blood glucose homeostasis that combines models of processes at the sub-cellular, cellular and organ level to describe the physiological system. The results of the analysis suggest three main points about the system: the mobilisation of calcium by glucagon plays a minor role in the regulation of glycogen metabolism; auto-regulation of hepatic glucose production by glucose is important in regulating blood glucose levels; time-delays between changes in blood glucose levels, the release of insulin by the pancreas and the eect of the hormone on hepatic glucose production are important in the possible onset of ultradian glucose oscillations. These results suggest possible directions for further study into the regulation of blood glucose

    Characterising and Testing Deep UV LEDs for Use in Space Applications

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    Deep ultraviolet (DUV) light sources are used to neutralise isolated test masses in highly sensitive space-based gravitational experiments. An example is the LISA Pathfinder charge management system, which uses low-pressure mercury lamps. A future gravitational-wave observatory such as eLISA will use UV light-emitting diodes (UV LEDs), which offer numerous advantages over traditional discharge lamps. Such devices have limited space heritage but are are now available from a number of commercial suppliers. Here we report on a test campaign that was carried out to quantify the general properties of three types of commercially available UV LEDs and demonstrate their suitability for use in space. Testing included general electrical and UV output measurements, spectral stability, pulsed performance, temperature dependence as well as thermal vacuum, radiation and vibration survivability

    Partly melted DNA conformations obtained with a probability peak finding method

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    Peaks in the probabilities of loops or bubbles, helical segments, and unzipping ends in melting DNA are found in this article using a peak finding method that maps the hierarchical structure of certain energy landscapes. The peaks indicate the alternative conformations that coexist in equilibrium and the range of their fluctuations. This yields a representation of the conformational ensemble at a given temperature, which is illustrated in a single diagram called a stitch profile. This article describes the methodology and discusses stitch profiles vs. the ordinary probability profiles using the phage lambda genome as an example.Comment: 11 pages, 9 figures; v3: major changes; v4: applications sectio

    Searching for a talking face: the effect of degrading the auditory signal

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    Previous research (e.g. McGurk and MacDonald, 1976) suggests that faces and voices are bound automatically, but recent evidence suggests that attention is involved in a task of searching for a talking face (Alsius and Soto-Faraco, 2011). We hypothesised that the processing demands of the stimuli may affect the amount of attentional resources required, and investigated what effect degrading the auditory stimulus had on the time taken to locate a talking face. Twenty participants were presented with between 2 and 4 faces articulating different sentences, and had to decide which of these faces matched the sentence that they heard. The results showed that in the least demanding auditory condition (clear speech in quiet), search times did not significantly increase when the number of faces increased. However, when speech was presented in background noise or was processed to simulate the information provided by a cochlear implant, search times increased as the number of faces increased. Thus, it seems that the amount of attentional resources required vary according to the processing demands of the auditory stimuli, and when processing load is increased then faces need to be individually attended to in order to complete the task. Based on these results we would expect cochlear-implant users to find the task of locating a talking face more attentionally demanding than normal hearing listeners

    Testing modified gravity with globular cluster velocity dispersions

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    Globular clusters (GCs) in the Milky Way have characteristic velocity dispersions that are consistent with the predictions of Newtonian gravity, and may be at odds with Modified Newtonian Dynamics (MOND). We discuss a modified gravity (MOG) theory that successfully predicts galaxy rotation curves, galaxy cluster masses and velocity dispersions, lensing, and cosmological observations, yet produces predictions consistent with Newtonian theory for smaller systems, such as GCs. MOG produces velocity dispersion predictions for GCs that are independent of the distance from the galactic center, which may not be the case for MOND. New observations of distant GCs may produce strong criteria that can be used to distinguish between competing gravitational theories.Comment: 4 pages, 2 figures; accepted for publication in Ap

    12/22/1978 Birthday Note

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    For more information on the Rosalyne S. Bernstein Papers, please visit the finding aid https://digitalcommons.usm.maine.edu/judaica_finding_aids/4/“\u3eHERE Brief note from Sumner T. Bernstein to Rosalyne S. Bernstein on the occasion of her 50th birthday.https://digitalcommons.usm.maine.edu/rbernstein_correspondence/1007/thumbnail.jp

    02/27/1946

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    Postcard to mother from Sumner Bernstein regarding weekend visit to Washington, D.C.https://digitalcommons.usm.maine.edu/sbernstein_correspondence/1244/thumbnail.jp

    Gelatin Standards for Elemental Quantification in Biological X-Ray Microanalysis

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    Standards for X-ray microanalysis (XRMA) can be prepared simply by dissolving measured amounts of gelatin and an appropriate salt in water, dipping grids in the solution, and allowing them to gel and dry. The present study was intended to assess the uniformity, reproducibility, and stability during irradiation of such standards. Visually, the gelatin films appear homogeneous, and XRMA measurements of different grid squares are generally in good agreement. The gelatin standards are susceptible to radiation damage, as judged by several criteria. These are: visible damage; variation of peak/continuum ratios with electron dose; anomalous values obtained with very thin standards; and changes in X-ray counts with prolonged irradiation. In general, the gelatin matrix appears to be lost during irradiation, but the elements within the matrix may be lost at the same rate as the gelatin, or faster, or more slowly
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