106 research outputs found

    Automatic landmarking for building biological shape models

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    We present a new method for automatic landmark extraction from the contours of biological specimens. Our ultimate goal is to enable automatic identification of biological specimens in photographs and drawings held in a database. We propose to use active appearance models for visual indexing of both photographs and drawings. Automatic landmark extraction will assist us in building the models. We describe the results of using our method on drawings and photographs of examples of diatoms, and present an active shape model built using automatically extracted data

    Proton Radiography of a Laser-Driven Implosion

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    Protons accelerated by a picosecond laser pulse have been used to radiograph a 500 mu m diameter capsule, imploded with 300 J of laser light in 6 symmetrically incident beams of wavelength 1.054 mu m and pulse length 1 ns. Point projection proton backlighting was used to characterize the density gradients at discrete times through the implosion. Asymmetries were diagnosed both during the early and stagnation stages of the implosion. Comparison with analytic scattering theory and simple Monte Carlo simulations were consistent with a 3 +/- 1 g/cm(3) core with diameter 85 +/- 10 mu m. Scaling simulations show that protons > 50 MeV are required to diagnose asymmetry in ignition scale conditions

    Electron microscopic demonstration of centrifugal nerve fibers in the human optic nerve

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    Electron microscopic views of centrifugal nerve fibers in the optic nerve stump of a 56-year-old man are presented. These nerve fibers had survived for 16 days after removal of the corresponding eyeball and exhibited terminal swellings pointing in a distal direction and indicating axoplasmic flow towards the removed eye. The centrifugal nerves in this adult lack any evidence of attempted regeneration that has earlier been observed under similar conditions in the optic nerve stump of a child. Zentrifugale (antidrome, efferente) Nervenfasern sind hier zum ersten Mal mit dem Elektronenmikroskop im menschlichen Sehnerven dargestellt worden. Diese Nervenfasern wurden in dem Sehnervenstumpf eines 56jährigen Mannes 16 Tage nach der Entfernung des dazugehörigen Auges gefunden. Endschwellungen dieser Nervenfasern waren distal ausgerichtet und deuteten damit einen Axoplasmafluß in Richtung des entfernten Auges an. Während deutliche Regenerationsversuche an den distalen Enden unterbrochener zentrifugaler Nervenfasern im Sehnervenstumpf eines Kindes früher beobachtet worden sind, fanden sich im Sehnerven dieses Erwachsenen keinerlei Zeichen von Regeneration der zentrifugalen Fasern.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47369/1/417_2004_Article_BF00414787.pd

    Open Peer Commentary and Author's Response

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    Mõttus gives the impression that composites, as well as other models in which traits are a result rather than a cause of their indicators, require “emergent properties” to have causal power. We argue that this is not necessary; composites can be considered causally relevant by themselves when they mediate the relation between their constituents and the outcome variable

    Statistical strategies for avoiding false discoveries in metabolomics and related experiments

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    Trends and transitions in the institutional environment for public and private science

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    The last quarter-century bore witness to a sea change in academic involvement with commerce. Widespread university-based efforts to identify, manage, and market intellectual property (IP) have accompanied broad shifts in the relationship between academic and proprietary approaches to the dissemination and use of science and engineering research. Such transformations are indicators of institutional changes at work in the environment faced by universities. This paper draws upon a fifteen-year panel (1981–1995) of university-level data for 87 research-intensive US campuses in order to document trends and transitions in relationships among multiple indicators of academic and commercial engagement. The institutional environment for public and private science is volatile, shifting in fits and starts from a situation conducive to organizational learning through high volume patenting to a more challenging arrangement that links indiscriminate pursuit of IP with declines in both the volume and impact of academic science. The pattern and timing of these transitions may support an enduring system of stratification that offers increasing returns to first-movers while limiting the opportunities available to universities that are later entrants to the commercial realm. Unpacking the systematic effects of university research commercialization requires focused attention on the sources and trajectories of profound institutional change.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42839/1/10734_2004_Article_2916.pd

    The trans-ancestral genomic architecture of glycemic traits

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    Glycemic traits are used to diagnose and monitor type 2 diabetes and cardiometabolic health. To date, most genetic studies of glycemic traits have focused on individuals of European ancestry. Here we aggregated genome-wide association studies comprising up to 281,416 individuals without diabetes (30% non-European ancestry) for whom fasting glucose, 2-h glucose after an oral glucose challenge, glycated hemoglobin and fasting insulin data were available. Trans-ancestry and single-ancestry meta-analyses identified 242 loci (99 novel; P < 5 x 10(-8)), 80% of which had no significant evidence of between-ancestry heterogeneity. Analyses restricted to individuals of European ancestry with equivalent sample size would have led to 24 fewer new loci. Compared with single-ancestry analyses, equivalent-sized trans-ancestry fine-mapping reduced the number of estimated variants in 99% credible sets by a median of 37.5%. Genomic-feature, gene-expression and gene-set analyses revealed distinct biological signatures for each trait, highlighting different underlying biological pathways. Our results increase our understanding of diabetes pathophysiology by using trans-ancestry studies for improved power and resolution.A trans-ancestry meta-analysis of GWAS of glycemic traits in up to 281,416 individuals identifies 99 novel loci, of which one quarter was found due to the multi-ancestry approach, which also improves fine-mapping of credible variant sets.Diabetes mellitus: pathophysiological changes and therap
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