856 research outputs found

    Reconstructing vectorised photographic images

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    We address the problem of representing captured images in the continuous mathematical space more usually associated with certain forms of drawn ('vector') images. Such an image is resolution-independent so can be used as a master for varying resolution-specific formats. We briefly describe the main features of a vectorising codec for photographic images, whose significance is that drawing programs can access images and image components as first-class vector objects. This paper focuses on the problem of rendering from the isochromic contour form of a vectorised image and demonstrates a new fill algorithm which could also be used in drawing generally. The fill method is described in terms of level set diffusion equations for clarity. Finally we show that image warping is both simplified and enhanced in this form and that we can demonstrate real histogram equalisation with genuinely rectangular histograms

    A Measurement of the Cosmic Ray Spectrum and Composition at the Knee

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    The energy spectrum and primary composition of cosmic rays with energy between 3×10143\times 10^{14} and 3\times10^{16}\unit{eV} have been studied using the CASA-BLANCA detector. CASA measured the charged particle distribution of air showers, while BLANCA measured the lateral distribution of Cherenkov light. The data are interpreted using the predictions of the CORSIKA air shower simulation coupled with four different hadronic interaction codes. The differential flux of cosmic rays measured by BLANCA exhibits a knee in the range of 2--3 PeV with a width of approximately 0.5 decades in primary energy. The power law indices of the differential flux below and above the knee are −2.72±0.02-2.72\pm0.02 and −2.95±0.02 -2.95\pm0.02. We present our data both as a mean depth of shower maximum and as a mean nuclear mass. A multi-component fit using four elemental species shows the same composition trends given by the mean quantities, and also indicates that QGSJET and VENUS are the preferred hadronic interaction models. We find that an initially mixed composition turns lighter between 1 and 3 PeV, and then becomes heavier with increasing energy above 3 PeV.Comment: 25 pages, 10 figures. Submitted to Astroparticle Physic

    Homocysteine in dogs with systemic inflammatory response syndrome

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    OBJECTIVES - To compare serum concentrations of homocysteine (Hcy) in dogs fitting the criteria for the systemic inflammatory response syndrome (SIRS) and healthy dogs, and compare these values to commonly measured B-vitamins. METHODS – Study dogs were classified into noninfectious SIRS or sepsis groups and blood was drawn on Day 1 of the patient’s hospitalization for the measurement of Hcy, folate and cobalamin concentrations. Hcy was measured in 51 clinically normal dogs to serve as the control group. RESULTS - A statistically significant difference was found between the Hcy concentrations of the healthy group when compared to noninfectious SIRS and sepsis groups. Hcy values were not correlated with folate, cobalamin or APPLEfast severity scores. Hcy concentrations were significantly lower in sick dogs when compared to the control group, which is dissimilar to the human population. CLINICAL SIGNIFCANCE - The clinical significance of Hcy changes in critically ill dogs is currently unknown.http://aac.asm.orghb2014ab201

    Optimising fisheries management in relation to tuna catches in the western central Pacific Ocean: A review of research priorities and opportunities

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    Some of the most important development goals for the countries and territories of the Western and Central Pacific Ocean (WCPO) involve the sustainable management of their fisheries in light of environmental, economic and social uncertainties. The responses of fish populations to variability in the marine environment have implications for decision making processes associated with resource management. There is still considerable uncertainty in estimating the responses of tuna populations to short-to-medium-term variability and longer-term change in the oceanic environment. A workshop was organised to examine how advances in oceanography, fisheries science and fisheries economics could be applied to the tuna fisheries of the WCPO and in doing so identify research priorities to improve understanding relevant to progressing management. Research priorities identified included: (i) improved parameterisation of end to end ecosystem model components, processes and feedbacks through expanded biological observations and incorporation of higher resolution climate models; (ii) development of seasonal and inter-annual forecasting tools enabling management responses to short-term variability in tuna distributions and abundances; (iii) improved understanding of the population dynamics of and the energy transfer efficiencies between food web components; (iv) assessment of the optimal value of access rights and overall fishery value under multiple scenarios of tuna distribution and abundance and influences on decision making by fisheries managers and fleets and (v) development of management strategy evaluation frameworks for utilisation in the implementing and testing of fishery management procedures and to help prioritise research directions and investment. Issues discussed and research priorities identified during the workshop have synergies with other internationally managed fisheries and therefore are applicable to many other fisheries

    The Composition of Cosmic Rays at the Knee

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    The observation of a small change in spectral slope, or 'knee' in the fluxes of cosmic rays near energies 10^15 eV has caused much speculation since its discovery over 40 years ago. The origin of this feature remains unknown. A small workshop to review some modern experimental measurements of this region was held at the Adler Planetarium in Chicago, USA in June 2000. This paper summarizes the results presented at this workshop and the discussion of their interpretation in the context of hadronic models of atmospheric airshowers.Comment: 36 pages, 10 figure

    Endemic fungal infections in solid organ and hematopoietic cell transplant recipients enrolled in the Transplant‐Associated Infection Surveillance Network ( TRANSNET )

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    Background Invasive fungal infections are a major cause of morbidity and mortality among solid organ transplant ( SOT ) and hematopoietic cell transplant ( HCT ) recipients, but few data have been reported on the epidemiology of endemic fungal infections in these populations. Methods Fifteen institutions belonging to the Transplant‐Associated Infection Surveillance Network prospectively enrolled SOT and HCT recipients with histoplasmosis, blastomycosis, or coccidioidomycosis occurring between March 2001 and March 2006. Results A total of 70 patients (64 SOT recipients and 6 HCT recipients) had infection with an endemic mycosis, including 52 with histoplasmosis, 9 with blastomycosis, and 9 with coccidioidomycosis. The 12‐month cumulative incidence rate among SOT recipients for histoplasmosis was 0.102%. Occurrence of infection was bimodal; 28 (40%) infections occurred in the first 6 months post transplantation, and 24 (34%) occurred between 2 and 11 years post transplantation. Three patients were documented to have acquired infection from the donor organ. Seven SOT recipients with histoplasmosis and 3 with coccidioidomycosis died (16%); no HCT recipient died. Conclusions This 5‐year multicenter prospective surveillance study found that endemic mycoses occur uncommonly in SOT and HCT recipients, and that the period at risk extends for years after transplantation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106980/1/tid12186.pd

    Twenty years online! A brief history of palaeontologia electronica

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    This issue marks the 20th anniversary of Palaeontologia Electronica (PE). From modest beginnings as a series of discussions on the PaleoNet listserver in 1996, it has become a well-recognised venue for publication and dissemination of research, techniques, and resources in palaeontology. The journal has many “firsts” to its credit, from the first species named on the internet, the first scientific journal with a plain-language abstract, and the first PDF “reprints” in palaeontology. Over 20 years PE also tried many new approaches that weren’t subsequently adopted by the broader scientific community, such as audio abstracts and animated journal covers. This anniversary issue gives us an opportunity to look back at the beginnings of the journal, its initial aims and aspirations, and to chronicle its evolution. It is as much a reflection of the changing nature of PE as it is a reminder of the larger scale changes that have taken place in the world of palaeontology, the internet, and our community over the past two decades

    Performance Analysis of the SHA-3 Candidates on Exotic Multi-core Architectures

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    The NIST hash function competition to design a new cryptographic hash standard 'SHA-3' is currently one of the hot topics in cryptologic research, its outcome heavily depends on the public evaluation of the remaining 14 candidates. There have been several cryptanalytic efforts to evaluate the security of these hash functions. Concurrently, invaluable benchmarking efforts have been made to measure the performance of the candidates on multiple architectures. In this paper we contribute to the latter; we evaluate the performance of all second-round SHA-3 candidates on two exotic platforms: the Cell Broadband Engine (Cell) and the NVIDIA Graphics Processing Units (GPUs). Firstly, we give performance estimates for each candidate based on the number of arithmetic instructions, which can be used as a starting point for evaluating the performance of the SHA-3 candidates on various platforms. Secondly, we use these generic estimates and Cell-/GPU-specific optimization techniques to give more precise figures for our target platforms, and finally, we present implementation results of all 10 non-AES based SHA-3 candidates

    Geniculo-Cortical Projection Diversity Revealed within the Mouse Visual Thalamus

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    This is the final version of the article. It was first available from PLOS via http://dx.doi.org/10.1371/journal.pone.0144846All dLGN cell co-ordinates, V1 injection sites, dLGN boundary coordinates, experimental protocols and analysis scripts are available for download from figshare at https://figshare.com/s/36c6d937b1844eec80a1.The mouse dorsal lateral geniculate nucleus (dLGN) is an intermediary between retina and primary visual cortex (V1). Recent investigations are beginning to reveal regional complexity in mouse dLGN. Using local injections of retrograde tracers into V1 of adult and neonatal mice, we examined the developing organisation of geniculate projection columns: the population of dLGN-V1 projection neurons that converge in cortex. Serial sectioning of the dLGN enabled the distribution of labelled projection neurons to be reconstructed and collated within a common standardised space. This enabled us to determine: the organisation of cells within the dLGN-V1 projection columns; their internal organisation (topology); and their order relative to V1 (topography). Here, we report parameters of projection columns that are highly variable in young animals and refined in the adult, exhibiting profiles consistent with shell and core zones of the dLGN. Additionally, such profiles are disrupted in adult animals with reduced correlated spontaneous activity during development. Assessing the variability between groups with partial least squares regression suggests that 4?6 cryptic lamina may exist along the length of the projection column. Our findings further spotlight the diversity of the mouse dLGN?an increasingly important model system for understanding the pre-cortical organisation and processing of visual information. Furthermore, our approach of using standardised spaces and pooling information across many animals will enhance future functional studies of the dLGN.Funding was provided by a Wellcome Trust grant jointly awarded to IDT and SJE (083205, www.wellcome.ac.uk), and by MRC PhD Studentships awarded to MNL and ACH (http://www.mrc.ac.uk/)

    Measurement of the branching fraction for ΄(1S)→τ+τ−\Upsilon (1S) \to \tau^+ \tau^-

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    We have studied the leptonic decay of the ΄(1S)\Upsilon (1S) resonance into tau pairs using the CLEO II detector. A clean sample of tau pair events is identified via events containing two charged particles where exactly one of the particles is an identified electron. We find B(΄(1S)→τ+τ−)=(2.61 ± 0.12 +0.09−0.13)B(\Upsilon(1S) \to \tau^+ \tau^-) = (2.61~\pm~0.12~{+0.09\atop{-0.13}})%. The result is consistent with expectations from lepton universality.Comment: 9 pages, RevTeX, two Postscript figures available upon request, CLNS 94/1297, CLEO 94-20 (submitted to Physics Letters B
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